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    //! Handles built-in and customizable compiler flag presets.
    //!
    //! [`Profiles`] is a collections of built-in profiles, and profiles defined
    //! in the root manifest and configurations.
    //!
    //! To start using a profile, most of the time you start from [`Profiles::new`],
    //! which does the followings:
    //!
    //! - Create a `Profiles` by merging profiles from configs onto the profile
    //!   from root manifest (see [`merge_config_profiles`]).
    //! - Add built-in profiles onto it (see [`Profiles::add_root_profiles`]).
    //! - Process profile inheritance for each profiles. (see [`Profiles::add_maker`]).
    //!
    //! Then you can query a [`Profile`] via [`Profiles::get_profile`], which respects
    //! the profile overridden hierarchy described in below. The [`Profile`] you get
    //! is basically an immutable struct containing the compiler flag presets.
    //!
    //! ## Profile overridden hierarchy
    //!
    //! Profile settings can be overridden for specific packages and build-time crates.
    //! The precedence is explained in [`ProfileMaker`].
    //! The algorithm happens within [`ProfileMaker::get_profile`].

    use crate::core::compiler::{CompileKind, CompileTarget, Unit};
    use crate::core::dependency::Artifact;
    use crate::core::resolver::features::FeaturesFor;
    use crate::core::Feature;
    use crate::core::{PackageId, PackageIdSpec, Resolve, Shell, Target, Workspace};
    use crate::util::interning::InternedString;
    use crate::util::toml::schema::TomlTrimPaths;
    use crate::util::toml::schema::TomlTrimPathsValue;
    use crate::util::toml::schema::{
        ProfilePackageSpec, StringOrBool, TomlDebugInfo, TomlProfile, TomlProfiles,
    };
    use crate::util::{closest_msg, config, CargoResult, Config};
    use anyhow::{bail, Context as _};
    use std::collections::{BTreeMap, HashMap, HashSet};
    use std::hash::Hash;
    use std::{cmp, fmt, hash};

    /// Collection of all profiles.
    ///
    /// To get a specific [`Profile`], you usually create this and call [`get_profile`] then.
    ///
    /// [`get_profile`]: Profiles::get_profile
    #[derive(Clone, Debug)]
    pub struct Profiles {
        /// Incremental compilation can be overridden globally via:
        /// - `CARGO_INCREMENTAL` environment variable.
        /// - `build.incremental` config value.
        incremental: Option<bool>,
        /// Map of profile name to directory name for that profile.
        dir_names: HashMap<InternedString, InternedString>,
        /// The profile makers. Key is the profile name.
        by_name: HashMap<InternedString, ProfileMaker>,
        /// The original profiles written by the user in the manifest and config.
        ///
        /// This is here to assist with error reporting, as the `ProfileMaker`
        /// values have the inherits chains all merged together.
        original_profiles: BTreeMap<InternedString, TomlProfile>,
        /// The profile the user requested to use.
        requested_profile: InternedString,
        /// The host target for rustc being used by this `Profiles`.
        rustc_host: InternedString,
    }

    impl Profiles {
        pub fn new(ws: &Workspace<'_>, requested_profile: InternedString) -> CargoResult<Profiles> {
            let config = ws.config();
            let incremental = match config.get_env_os("CARGO_INCREMENTAL") {
                Some(v) => Some(v == "1"),
                None => config.build_config()?.incremental,
            };
            let mut profiles = merge_config_profiles(ws, requested_profile)?;
            let rustc_host = ws.config().load_global_rustc(Some(ws))?.host;

            let mut profile_makers = Profiles {
                incremental,
                dir_names: Self::predefined_dir_names(),
                by_name: HashMap::new(),
                original_profiles: profiles.clone(),
                requested_profile,
                rustc_host,
            };

            let trim_paths_enabled = ws.unstable_features().is_enabled(Feature::trim_paths())
                || config.cli_unstable().trim_paths;
            Self::add_root_profiles(&mut profile_makers, &profiles, trim_paths_enabled);

            // Merge with predefined profiles.
            use std::collections::btree_map::Entry;
            for (predef_name, mut predef_prof) in Self::predefined_profiles().into_iter() {
                match profiles.entry(InternedString::new(predef_name)) {
                    Entry::Vacant(vac) => {
                        vac.insert(predef_prof);
                    }
                    Entry::Occupied(mut oc) => {
                        // Override predefined with the user-provided Toml.
                        let r = oc.get_mut();
                        predef_prof.merge(r);
                        *r = predef_prof;
                    }
                }
            }

            for (name, profile) in &profiles {
                profile_makers.add_maker(*name, profile, &profiles)?;
            }
            // Verify that the requested profile is defined *somewhere*.
            // This simplifies the API (no need for CargoResult), and enforces
            // assumptions about how config profiles are loaded.
            profile_makers.get_profile_maker(&requested_profile)?;
            Ok(profile_makers)
        }

        /// Returns the hard-coded directory names for built-in profiles.
        fn predefined_dir_names() -> HashMap<InternedString, InternedString> {
            [
                (InternedString::new("dev"), InternedString::new("debug")),
                (InternedString::new("test"), InternedString::new("debug")),
                (InternedString::new("bench"), InternedString::new("release")),
            ]
            .into()
        }

        /// Initialize `by_name` with the two "root" profiles, `dev`, and
        /// `release` given the user's definition.
        fn add_root_profiles(
            profile_makers: &mut Profiles,
            profiles: &BTreeMap<InternedString, TomlProfile>,
            trim_paths_enabled: bool,
        ) {
            profile_makers.by_name.insert(
                InternedString::new("dev"),
                ProfileMaker::new(Profile::default_dev(), profiles.get("dev").cloned()),
            );

            profile_makers.by_name.insert(
                InternedString::new("release"),
                ProfileMaker::new(
                    Profile::default_release(trim_paths_enabled),
                    profiles.get("release").cloned(),
                ),
            );
        }

        /// Returns the built-in profiles (not including dev/release, which are
        /// "root" profiles).
        fn predefined_profiles() -> Vec<(&'static str, TomlProfile)> {
            vec![
                (
                    "bench",
                    TomlProfile {
                        inherits: Some(String::from("release")),
                        ..TomlProfile::default()
                    },
                ),
                (
                    "test",
                    TomlProfile {
                        inherits: Some(String::from("dev")),
                        ..TomlProfile::default()
                    },
                ),
                (
                    "doc",
                    TomlProfile {
                        inherits: Some(String::from("dev")),
                        ..TomlProfile::default()
                    },
                ),
            ]
        }

        /// Creates a `ProfileMaker`, and inserts it into `self.by_name`.
        fn add_maker(
            &mut self,
            name: InternedString,
            profile: &TomlProfile,
            profiles: &BTreeMap<InternedString, TomlProfile>,
        ) -> CargoResult<()> {
            match &profile.dir_name {
                None => {}
                Some(dir_name) => {
                    self.dir_names.insert(name, InternedString::new(dir_name));
                }
            }

            // dev/release are "roots" and don't inherit.
            if name == "dev" || name == "release" {
                if profile.inherits.is_some() {
                    bail!(
                        "`inherits` must not be specified in root profile `{}`",
                        name
                    );
                }
                // Already inserted from `add_root_profiles`, no need to do anything.
                return Ok(());
            }

            // Keep track for inherits cycles.
            let mut set = HashSet::new();
            set.insert(name);
            let maker = self.process_chain(name, profile, &mut set, profiles)?;
            self.by_name.insert(name, maker);
            Ok(())
        }

        /// Build a `ProfileMaker` by recursively following the `inherits` setting.
        ///
        /// * `name`: The name of the profile being processed.
        /// * `profile`: The TOML profile being processed.
        /// * `set`: Set of profiles that have been visited, used to detect cycles.
        /// * `profiles`: Map of all TOML profiles.
        ///
        /// Returns a `ProfileMaker` to be used for the given named profile.
        fn process_chain(
            &mut self,
            name: InternedString,
            profile: &TomlProfile,
            set: &mut HashSet<InternedString>,
            profiles: &BTreeMap<InternedString, TomlProfile>,
        ) -> CargoResult<ProfileMaker> {
            let mut maker = match &profile.inherits {
                Some(inherits_name) if inherits_name == "dev" || inherits_name == "release" => {
                    // These are the root profiles added in `add_root_profiles`.
                    self.get_profile_maker(&inherits_name).unwrap().clone()
                }
                Some(inherits_name) => {
                    let inherits_name = InternedString::new(&inherits_name);
                    if !set.insert(inherits_name) {
                        bail!(
                            "profile inheritance loop detected with profile `{}` inheriting `{}`",
                            name,
                            inherits_name
                        );
                    }

                    match profiles.get(&inherits_name) {
                        None => {
                            bail!(
                                "profile `{}` inherits from `{}`, but that profile is not defined",
                                name,
                                inherits_name
                            );
                        }
                        Some(parent) => self.process_chain(inherits_name, parent, set, profiles)?,
                    }
                }
                None => {
                    bail!(
                        "profile `{}` is missing an `inherits` directive \
                         (`inherits` is required for all profiles except `dev` or `release`)",
                        name
                    );
                }
            };
            match &mut maker.toml {
                Some(toml) => toml.merge(profile),
                None => maker.toml = Some(profile.clone()),
            };
            Ok(maker)
        }

        /// Retrieves the profile for a target.
        /// `is_member` is whether or not this package is a member of the
        /// workspace.
        pub fn get_profile(
            &self,
            pkg_id: PackageId,
            is_member: bool,
            is_local: bool,
            unit_for: UnitFor,
            kind: CompileKind,
        ) -> Profile {
            let maker = self.get_profile_maker(&self.requested_profile).unwrap();
            let mut profile = maker.get_profile(Some(pkg_id), is_member, unit_for.is_for_host());

            // Dealing with `panic=abort` and `panic=unwind` requires some special
            // treatment. Be sure to process all the various options here.
            match unit_for.panic_setting() {
                PanicSetting::AlwaysUnwind => profile.panic = PanicStrategy::Unwind,
                PanicSetting::ReadProfile => {}
            }

            // Default macOS debug information to being stored in the "unpacked"
            // split-debuginfo format. At the time of this writing that's the only
            // platform which has a stable `-Csplit-debuginfo` option for rustc,
            // and it's typically much faster than running `dsymutil` on all builds
            // in incremental cases.
            if profile.debuginfo.is_turned_on() && profile.split_debuginfo.is_none() {
                let target = match &kind {
                    CompileKind::Host => self.rustc_host.as_str(),
                    CompileKind::Target(target) => target.short_name(),
                };
                if target.contains("-apple-") {
                    profile.split_debuginfo = Some(InternedString::new("unpacked"));
                }
            }

            // Incremental can be globally overridden.
            if let Some(v) = self.incremental {
                profile.incremental = v;
            }

            // Only enable incremental compilation for sources the user can
            // modify (aka path sources). For things that change infrequently,
            // non-incremental builds yield better performance in the compiler
            // itself (aka crates.io / git dependencies)
            //
            // (see also https://github.com/rust-lang/cargo/issues/3972)
            if !is_local {
                profile.incremental = false;
            }
            profile.name = self.requested_profile;
            profile
        }

        /// The profile for *running* a `build.rs` script is only used for setting
        /// a few environment variables. To ensure proper de-duplication of the
        /// running `Unit`, this uses a stripped-down profile (so that unrelated
        /// profile flags don't cause `build.rs` to needlessly run multiple
        /// times).
        pub fn get_profile_run_custom_build(&self, for_unit_profile: &Profile) -> Profile {
            let mut result = Profile::default();
            result.name = for_unit_profile.name;
            result.root = for_unit_profile.root;
            result.debuginfo = for_unit_profile.debuginfo;
            result.opt_level = for_unit_profile.opt_level;
            result.trim_paths = for_unit_profile.trim_paths.clone();
            result
        }

        /// This returns the base profile. This is currently used for the
        /// `[Finished]` line. It is not entirely accurate, since it doesn't
        /// select for the package that was actually built.
        pub fn base_profile(&self) -> Profile {
            let profile_name = self.requested_profile;
            let maker = self.get_profile_maker(&profile_name).unwrap();
            maker.get_profile(None, /*is_member*/ true, /*is_for_host*/ false)
        }

        /// Gets the directory name for a profile, like `debug` or `release`.
        pub fn get_dir_name(&self) -> InternedString {
            *self
                .dir_names
                .get(&self.requested_profile)
                .unwrap_or(&self.requested_profile)
        }

        /// Used to check for overrides for non-existing packages.
        pub fn validate_packages(
            &self,
            profiles: Option<&TomlProfiles>,
            shell: &mut Shell,
            resolve: &Resolve,
        ) -> CargoResult<()> {
            for (name, profile) in &self.by_name {
                // If the user did not specify an override, skip this. This is here
                // to avoid generating errors for inherited profiles which don't
                // specify package overrides. The `by_name` profile has had the inherits
                // chain merged, so we need to look at the original source to check
                // if an override was specified.
                if self
                    .original_profiles
                    .get(name)
                    .and_then(|orig| orig.package.as_ref())
                    .is_none()
                {
                    continue;
                }
                let found = validate_packages_unique(resolve, name, &profile.toml)?;
                // We intentionally do not validate unmatched packages for config
                // profiles, in case they are defined in a central location. This
                // iterates over the manifest profiles only.
                if let Some(profiles) = profiles {
                    if let Some(toml_profile) = profiles.get(name) {
                        validate_packages_unmatched(shell, resolve, name, toml_profile, &found)?;
                    }
                }
            }
            Ok(())
        }

        /// Returns the profile maker for the given profile name.
        fn get_profile_maker(&self, name: &str) -> CargoResult<&ProfileMaker> {
            self.by_name
                .get(name)
                .ok_or_else(|| anyhow::format_err!("profile `{}` is not defined", name))
        }
    }

    /// An object used for handling the profile hierarchy.
    ///
    /// The precedence of profiles are (first one wins):
    ///
    /// - Profiles in `.cargo/config` files (using same order as below).
    /// - `[profile.dev.package.name]` -- a named package.
    /// - `[profile.dev.package."*"]` -- this cannot apply to workspace members.
    /// - `[profile.dev.build-override]` -- this can only apply to `build.rs` scripts
    ///   and their dependencies.
    /// - `[profile.dev]`
    /// - Default (hard-coded) values.
    #[derive(Debug, Clone)]
    struct ProfileMaker {
        /// The starting, hard-coded defaults for the profile.
        default: Profile,
        /// The TOML profile defined in `Cargo.toml` or config.
        ///
        /// This is None if the user did not specify one, in which case the
        /// `default` is used. Note that the built-in defaults for test/bench/doc
        /// always set this since they need to declare the `inherits` value.
        toml: Option<TomlProfile>,
    }

    impl ProfileMaker {
        /// Creates a new `ProfileMaker`.
        ///
        /// Note that this does not process `inherits`, the caller is responsible for that.
        fn new(default: Profile, toml: Option<TomlProfile>) -> ProfileMaker {
            ProfileMaker { default, toml }
        }

        /// Generates a new `Profile`.
        fn get_profile(
            &self,
            pkg_id: Option<PackageId>,
            is_member: bool,
            is_for_host: bool,
        ) -> Profile {
            let mut profile = self.default.clone();

            // First apply profile-specific settings, things like
            // `[profile.release]`
            if let Some(toml) = &self.toml {
                merge_profile(&mut profile, toml);
            }

            // Next start overriding those settings. First comes build dependencies
            // which default to opt-level 0...
            if is_for_host {
                // For-host units are things like procedural macros, build scripts, and
                // their dependencies. For these units most projects simply want them
                // to compile quickly and the runtime doesn't matter too much since
                // they tend to process very little data. For this reason we default
                // them to a "compile as quickly as possible" mode which for now means
                // basically turning down the optimization level and avoid limiting
                // codegen units. This ensures that we spend little time optimizing as
                // well as enabling parallelism by not constraining codegen units.
                profile.opt_level = InternedString::new("0");
                profile.codegen_units = None;

                // For build dependencies, we usually don't need debuginfo, and
                // removing it will compile faster. However, that can conflict with
                // a unit graph optimization, reusing units that are shared between
                // build dependencies and runtime dependencies: when the runtime
                // target is the same as the build host, we only need to build a
                // dependency once and reuse the results, instead of building twice.
                // We defer the choice of the debuginfo level until we can check if
                // a unit is shared. If that's the case, we'll use the deferred value
                // below so the unit can be reused, otherwise we can avoid emitting
                // the unit's debuginfo.
                profile.debuginfo = DebugInfo::Deferred(profile.debuginfo.into_inner());
            }
            // ... and next comes any other sorts of overrides specified in
            // profiles, such as `[profile.release.build-override]` or
            // `[profile.release.package.foo]`
            if let Some(toml) = &self.toml {
                merge_toml_overrides(pkg_id, is_member, is_for_host, &mut profile, toml);
            }
            profile
        }
    }

    /// Merge package and build overrides from the given TOML profile into the given `Profile`.
    fn merge_toml_overrides(
        pkg_id: Option<PackageId>,
        is_member: bool,
        is_for_host: bool,
        profile: &mut Profile,
        toml: &TomlProfile,
    ) {
        if is_for_host {
            if let Some(build_override) = &toml.build_override {
                merge_profile(profile, build_override);
            }
        }
        if let Some(overrides) = toml.package.as_ref() {
            if !is_member {
                if let Some(all) = overrides.get(&ProfilePackageSpec::All) {
                    merge_profile(profile, all);
                }
            }
            if let Some(pkg_id) = pkg_id {
                let mut matches = overrides
                    .iter()
                    .filter_map(|(key, spec_profile)| match *key {
                        ProfilePackageSpec::All => None,
                        ProfilePackageSpec::Spec(ref s) => {
                            if s.matches(pkg_id) {
                                Some(spec_profile)
                            } else {
                                None
                            }
                        }
                    });
                if let Some(spec_profile) = matches.next() {
                    merge_profile(profile, spec_profile);
                    // `validate_packages` should ensure that there are
                    // no additional matches.
                    assert!(
                        matches.next().is_none(),
                        "package `{}` matched multiple package profile overrides",
                        pkg_id
                    );
                }
            }
        }
    }

    /// Merge the given TOML profile into the given `Profile`.
    ///
    /// Does not merge overrides (see `merge_toml_overrides`).
    fn merge_profile(profile: &mut Profile, toml: &TomlProfile) {
        if let Some(ref opt_level) = toml.opt_level {
            profile.opt_level = InternedString::new(&opt_level.0);
        }
        match toml.lto {
            Some(StringOrBool::Bool(b)) => profile.lto = Lto::Bool(b),
            Some(StringOrBool::String(ref n)) if is_off(n.as_str()) => profile.lto = Lto::Off,
            Some(StringOrBool::String(ref n)) => profile.lto = Lto::Named(InternedString::new(n)),
            None => {}
        }
        if toml.codegen_backend.is_some() {
            profile.codegen_backend = toml.codegen_backend.as_ref().map(InternedString::from);
        }
        if toml.codegen_units.is_some() {
            profile.codegen_units = toml.codegen_units;
        }
        if let Some(debuginfo) = toml.debug {
            profile.debuginfo = DebugInfo::Resolved(debuginfo);
        }
        if let Some(debug_assertions) = toml.debug_assertions {
            profile.debug_assertions = debug_assertions;
        }
        if let Some(split_debuginfo) = &toml.split_debuginfo {
            profile.split_debuginfo = Some(InternedString::new(split_debuginfo));
        }
        if let Some(rpath) = toml.rpath {
            profile.rpath = rpath;
        }
        if let Some(panic) = &toml.panic {
            profile.panic = match panic.as_str() {
                "unwind" => PanicStrategy::Unwind,
                "abort" => PanicStrategy::Abort,
                // This should be validated in TomlProfile::validate
                _ => panic!("Unexpected panic setting `{}`", panic),
            };
        }
        if let Some(overflow_checks) = toml.overflow_checks {
            profile.overflow_checks = overflow_checks;
        }
        if let Some(incremental) = toml.incremental {
            profile.incremental = incremental;
        }
        if let Some(flags) = &toml.rustflags {
            profile.rustflags = flags.iter().map(InternedString::from).collect();
        }
        if let Some(trim_paths) = &toml.trim_paths {
            profile.trim_paths = Some(trim_paths.clone());
        }
        profile.strip = match toml.strip {
            Some(StringOrBool::Bool(true)) => Strip::Named(InternedString::new("symbols")),
            None | Some(StringOrBool::Bool(false)) => Strip::None,
            Some(StringOrBool::String(ref n)) if n.as_str() == "none" => Strip::None,
            Some(StringOrBool::String(ref n)) => Strip::Named(InternedString::new(n)),
        };
    }

    /// The root profile (dev/release).
    ///
    /// This is currently only used for the `PROFILE` env var for build scripts
    /// for backwards compatibility. We should probably deprecate `PROFILE` and
    /// encourage using things like `DEBUG` and `OPT_LEVEL` instead.
    #[derive(Clone, Copy, Eq, PartialOrd, Ord, PartialEq, Debug)]
    pub enum ProfileRoot {
        Release,
        Debug,
    }

    /// Profile settings used to determine which compiler flags to use for a
    /// target.
    #[derive(Clone, Eq, PartialOrd, Ord, serde::Serialize)]
    pub struct Profile {
        pub name: InternedString,
        pub opt_level: InternedString,
        #[serde(skip)] // named profiles are unstable
        pub root: ProfileRoot,
        pub lto: Lto,
        // `None` means use rustc default.
        pub codegen_backend: Option<InternedString>,
        // `None` means use rustc default.
        pub codegen_units: Option<u32>,
        pub debuginfo: DebugInfo,
        pub split_debuginfo: Option<InternedString>,
        pub debug_assertions: bool,
        pub overflow_checks: bool,
        pub rpath: bool,
        pub incremental: bool,
        pub panic: PanicStrategy,
        pub strip: Strip,
        #[serde(skip_serializing_if = "Vec::is_empty")] // remove when `rustflags` is stablized
        // Note that `rustflags` is used for the cargo-feature `profile_rustflags`
        pub rustflags: Vec<InternedString>,
        // remove when `-Ztrim-paths` is stablized
        #[serde(skip_serializing_if = "Option::is_none")]
        pub trim_paths: Option<TomlTrimPaths>,
    }

    impl Default for Profile {
        fn default() -> Profile {
            Profile {
                name: InternedString::new(""),
                opt_level: InternedString::new("0"),
                root: ProfileRoot::Debug,
                lto: Lto::Bool(false),
                codegen_backend: None,
                codegen_units: None,
                debuginfo: DebugInfo::Resolved(TomlDebugInfo::None),
                debug_assertions: false,
                split_debuginfo: None,
                overflow_checks: false,
                rpath: false,
                incremental: false,
                panic: PanicStrategy::Unwind,
                strip: Strip::None,
                rustflags: vec![],
                trim_paths: None,
            }
        }
    }

    compact_debug! {
        impl fmt::Debug for Profile {
            fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
                let (default, default_name) = match self.name.as_str() {
                    "dev" => (Profile::default_dev(), "default_dev()"),
                    "release" => (Profile::default_release(false), "default_release()"),
                    _ => (Profile::default(), "default()"),
                };
                [debug_the_fields(
                    name
                    opt_level
                    lto
                    root
                    codegen_backend
                    codegen_units
                    debuginfo
                    split_debuginfo
                    debug_assertions
                    overflow_checks
                    rpath
                    incremental
                    panic
                    strip
                    rustflags
                    trim_paths
                )]
            }
        }
    }

    impl fmt::Display for Profile {
        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
            write!(f, "Profile({})", self.name)
        }
    }

    impl hash::Hash for Profile {
        fn hash<H>(&self, state: &mut H)
        where
            H: hash::Hasher,
        {
            self.comparable().hash(state);
        }
    }

    impl cmp::PartialEq for Profile {
        fn eq(&self, other: &Self) -> bool {
            self.comparable() == other.comparable()
        }
    }

    impl Profile {
        /// Returns a built-in `dev` profile.
        fn default_dev() -> Profile {
            Profile {
                name: InternedString::new("dev"),
                root: ProfileRoot::Debug,
                debuginfo: DebugInfo::Resolved(TomlDebugInfo::Full),
                debug_assertions: true,
                overflow_checks: true,
                incremental: true,
                ..Profile::default()
            }
        }

        /// Returns a built-in `release` profile.
        fn default_release(trim_paths_enabled: bool) -> Profile {
            let trim_paths = trim_paths_enabled.then(|| TomlTrimPathsValue::Object.into());
            Profile {
                name: InternedString::new("release"),
                root: ProfileRoot::Release,
                opt_level: InternedString::new("3"),
                trim_paths,
                ..Profile::default()
            }
        }

        /// Compares all fields except `name`, which doesn't affect compilation.
        /// This is necessary for `Unit` deduplication for things like "test" and
        /// "dev" which are essentially the same.
        fn comparable(&self) -> impl Hash + Eq + '_ {
            (
                self.opt_level,
                self.lto,
                self.codegen_backend,
                self.codegen_units,
                self.debuginfo,
                self.split_debuginfo,
                self.debug_assertions,
                self.overflow_checks,
                self.rpath,
                (self.incremental, self.panic, self.strip),
                &self.rustflags,
                &self.trim_paths,
            )
        }
    }

    /// The debuginfo level setting.
    ///
    /// This is semantically a [`TomlDebugInfo`], and should be used as so via the
    /// [`DebugInfo::into_inner`] method for all intents and purposes.
    ///
    /// Internally, it's used to model a debuginfo level whose value can be deferred
    /// for optimization purposes: host dependencies usually don't need the same
    /// level as target dependencies. For dependencies that are shared between the
    /// two however, that value also affects reuse: different debuginfo levels would
    /// cause to build a unit twice. By deferring the choice until we know
    /// whether to choose the optimized value or the default value, we can make sure
    /// the unit is only built once and the unit graph is still optimized.
    #[derive(Debug, Copy, Clone, serde::Serialize)]
    #[serde(untagged)]
    pub enum DebugInfo {
        /// A debuginfo level that is fixed and will not change.
        ///
        /// This can be set by a profile, user, or default value.
        Resolved(TomlDebugInfo),
        /// For internal purposes: a deferred debuginfo level that can be optimized
        /// away, but has this value otherwise.
        ///
        /// Behaves like `Resolved` in all situations except for the default build
        /// dependencies profile: whenever a build dependency is not shared with
        /// runtime dependencies, this level is weakened to a lower level that is
        /// faster to build (see [`DebugInfo::weaken`]).
        ///
        /// In all other situations, this level value will be the one to use.
        Deferred(TomlDebugInfo),
    }

    impl DebugInfo {
        /// The main way to interact with this debuginfo level, turning it into a [`TomlDebugInfo`].
        pub fn into_inner(self) -> TomlDebugInfo {
            match self {
                DebugInfo::Resolved(v) | DebugInfo::Deferred(v) => v,
            }
        }

        /// Returns true if any debuginfo will be generated. Helper
        /// for a common operation on the usual `Option` representation.
        pub(crate) fn is_turned_on(&self) -> bool {
            !matches!(self.into_inner(), TomlDebugInfo::None)
        }

        pub(crate) fn is_deferred(&self) -> bool {
            matches!(self, DebugInfo::Deferred(_))
        }

        /// Force the deferred, preferred, debuginfo level to a finalized explicit value.
        pub(crate) fn finalize(self) -> Self {
            match self {
                DebugInfo::Deferred(v) => DebugInfo::Resolved(v),
                _ => self,
            }
        }

        /// Reset to the lowest level: no debuginfo.
        pub(crate) fn weaken(self) -> Self {
            DebugInfo::Resolved(TomlDebugInfo::None)
        }
    }

    impl PartialEq for DebugInfo {
        fn eq(&self, other: &DebugInfo) -> bool {
            self.into_inner().eq(&other.into_inner())
        }
    }

    impl Eq for DebugInfo {}

    impl Hash for DebugInfo {
        fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
            self.into_inner().hash(state);
        }
    }

    impl PartialOrd for DebugInfo {
        fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
            self.into_inner().partial_cmp(&other.into_inner())
        }
    }

    impl Ord for DebugInfo {
        fn cmp(&self, other: &Self) -> std::cmp::Ordering {
            self.into_inner().cmp(&other.into_inner())
        }
    }

    /// The link-time-optimization setting.
    #[derive(Clone, Copy, PartialEq, Eq, Debug, Hash, PartialOrd, Ord)]
    pub enum Lto {
        /// Explicitly no LTO, disables thin-LTO.
        Off,
        /// True = "Fat" LTO
        /// False = rustc default (no args), currently "thin LTO"
        Bool(bool),
        /// Named LTO settings like "thin".
        Named(InternedString),
    }

    impl serde::ser::Serialize for Lto {
        fn serialize<S>(&self, s: S) -> Result<S::Ok, S::Error>
        where
            S: serde::ser::Serializer,
        {
            match self {
                Lto::Off => "off".serialize(s),
                Lto::Bool(b) => b.to_string().serialize(s),
                Lto::Named(n) => n.serialize(s),
            }
        }
    }

    /// The `panic` setting.
    #[derive(Clone, Copy, PartialEq, Eq, Debug, Hash, PartialOrd, Ord, serde::Serialize)]
    #[serde(rename_all = "lowercase")]
    pub enum PanicStrategy {
        Unwind,
        Abort,
    }

    impl fmt::Display for PanicStrategy {
        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
            match *self {
                PanicStrategy::Unwind => "unwind",
                PanicStrategy::Abort => "abort",
            }
            .fmt(f)
        }
    }

    /// The setting for choosing which symbols to strip
    #[derive(
        Clone, Copy, PartialEq, Eq, Debug, Hash, PartialOrd, Ord, serde::Serialize, serde::Deserialize,
    )]
    #[serde(rename_all = "lowercase")]
    pub enum Strip {
        /// Don't remove any symbols
        None,
        /// Named Strip settings
        Named(InternedString),
    }

    impl fmt::Display for Strip {
        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
            match *self {
                Strip::None => "none",
                Strip::Named(s) => s.as_str(),
            }
            .fmt(f)
        }
    }

    /// Flags used in creating `Unit`s to indicate the purpose for the target, and
    /// to ensure the target's dependencies have the correct settings.
    ///
    /// This means these are passed down from the root of the dependency tree to apply
    /// to most child dependencies.
    #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash, Ord, PartialOrd)]
    pub struct UnitFor {
        /// A target for `build.rs` or any of its dependencies, or a proc-macro or
        /// any of its dependencies. This enables `build-override` profiles for
        /// these targets.
        ///
        /// An invariant is that if `host_features` is true, `host` must be true.
        ///
        /// Note that this is `true` for `RunCustomBuild` units, even though that
        /// unit should *not* use build-override profiles. This is a bit of a
        /// special case. When computing the `RunCustomBuild` unit, it manually
        /// uses the `get_profile_run_custom_build` method to get the correct
        /// profile information for the unit. `host` needs to be true so that all
        /// of the dependencies of that `RunCustomBuild` unit have this flag be
        /// sticky (and forced to `true` for all further dependencies) — which is
        /// the whole point of `UnitFor`.
        host: bool,
        /// A target for a build dependency or proc-macro (or any of its
        /// dependencies). This is used for computing features of build
        /// dependencies and proc-macros independently of other dependency kinds.
        ///
        /// The subtle difference between this and `host` is that the build script
        /// for a non-host package sets this to `false` because it wants the
        /// features of the non-host package (whereas `host` is true because the
        /// build script is being built for the host). `host_features` becomes
        /// `true` for build-dependencies or proc-macros, or any of their
        /// dependencies. For example, with this dependency tree:
        ///
        /// ```text
        /// foo
        /// ├── foo build.rs
        /// │   └── shared_dep (BUILD dependency)
        /// │       └── shared_dep build.rs
        /// └── shared_dep (Normal dependency)
        ///     └── shared_dep build.rs
        /// ```
        ///
        /// In this example, `foo build.rs` is HOST=true, HOST_FEATURES=false.
        /// This is so that `foo build.rs` gets the profile settings for build
        /// scripts (HOST=true) and features of foo (HOST_FEATURES=false) because
        /// build scripts need to know which features their package is being built
        /// with.
        ///
        /// But in the case of `shared_dep`, when built as a build dependency,
        /// both flags are true (it only wants the build-dependency features).
        /// When `shared_dep` is built as a normal dependency, then `shared_dep
        /// build.rs` is HOST=true, HOST_FEATURES=false for the same reasons that
        /// foo's build script is set that way.
        host_features: bool,
        /// How Cargo processes the `panic` setting or profiles.
        panic_setting: PanicSetting,

        /// The compile kind of the root unit for which artifact dependencies are built.
        /// This is required particularly for the `target = "target"` setting of artifact
        /// dependencies which mean to inherit the `--target` specified on the command-line.
        /// However, that is a multi-value argument and root units are already created to
        /// reflect one unit per --target. Thus we have to build one artifact with the
        /// correct target for each of these trees.
        /// Note that this will always be set as we don't initially know if there are
        /// artifacts that make use of it.
        root_compile_kind: CompileKind,

        /// This is only set for artifact dependencies which have their
        /// `<target-triple>|target` set.
        /// If so, this information is used as part of the key for resolving their features,
        /// allowing for target-dependent feature resolution within the entire dependency tree.
        /// Note that this target corresponds to the target used to build the units in that
        /// dependency tree, too, but this copy of it is specifically used for feature lookup.
        artifact_target_for_features: Option<CompileTarget>,
    }

    /// How Cargo processes the `panic` setting or profiles.
    ///
    /// This is done to handle test/benches inheriting from dev/release,
    /// as well as forcing `for_host` units to always unwind.
    /// It also interacts with [`-Z panic-abort-tests`].
    ///
    /// [`-Z panic-abort-tests`]: https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#panic-abort-tests
    #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash, Ord, PartialOrd)]
    enum PanicSetting {
        /// Used to force a unit to always be compiled with the `panic=unwind`
        /// strategy, notably for build scripts, proc macros, etc.
        AlwaysUnwind,

        /// Indicates that this unit will read its `profile` setting and use
        /// whatever is configured there.
        ReadProfile,
    }

    impl UnitFor {
        /// A unit for a normal target/dependency (i.e., not custom build,
        /// proc macro/plugin, or test/bench).
        pub fn new_normal(root_compile_kind: CompileKind) -> UnitFor {
            UnitFor {
                host: false,
                host_features: false,
                panic_setting: PanicSetting::ReadProfile,
                root_compile_kind,
                artifact_target_for_features: None,
            }
        }

        /// A unit for a custom build script or proc-macro or its dependencies.
        ///
        /// The `host_features` parameter is whether or not this is for a build
        /// dependency or proc-macro (something that requires being built "on the
        /// host"). Build scripts for non-host units should use `false` because
        /// they want to use the features of the package they are running for.
        pub fn new_host(host_features: bool, root_compile_kind: CompileKind) -> UnitFor {
            UnitFor {
                host: true,
                host_features,
                // Force build scripts to always use `panic=unwind` for now to
                // maximally share dependencies with procedural macros.
                panic_setting: PanicSetting::AlwaysUnwind,
                root_compile_kind,
                artifact_target_for_features: None,
            }
        }

        /// A unit for a compiler plugin or their dependencies.
        pub fn new_compiler(root_compile_kind: CompileKind) -> UnitFor {
            UnitFor {
                host: false,
                // The feature resolver doesn't know which dependencies are
                // plugins, so for now plugins don't split features. Since plugins
                // are mostly deprecated, just leave this as false.
                host_features: false,
                // Force plugins to use `panic=abort` so panics in the compiler do
                // not abort the process but instead end with a reasonable error
                // message that involves catching the panic in the compiler.
                panic_setting: PanicSetting::AlwaysUnwind,
                root_compile_kind,
                artifact_target_for_features: None,
            }
        }

        /// A unit for a test/bench target or their dependencies.
        ///
        /// Note that `config` is taken here for unstable CLI features to detect
        /// whether `panic=abort` is supported for tests. Historical versions of
        /// rustc did not support this, but newer versions do with an unstable
        /// compiler flag.
        pub fn new_test(config: &Config, root_compile_kind: CompileKind) -> UnitFor {
            UnitFor {
                host: false,
                host_features: false,
                // We're testing out an unstable feature (`-Zpanic-abort-tests`)
                // which inherits the panic setting from the dev/release profile
                // (basically avoid recompiles) but historical defaults required
                // that we always unwound.
                panic_setting: if config.cli_unstable().panic_abort_tests {
                    PanicSetting::ReadProfile
                } else {
                    PanicSetting::AlwaysUnwind
                },
                root_compile_kind,
                artifact_target_for_features: None,
            }
        }

        /// This is a special case for unit tests of a proc-macro.
        ///
        /// Proc-macro unit tests are forced to be run on the host.
        pub fn new_host_test(config: &Config, root_compile_kind: CompileKind) -> UnitFor {
            let mut unit_for = UnitFor::new_test(config, root_compile_kind);
            unit_for.host = true;
            unit_for.host_features = true;
            unit_for
        }

        /// Returns a new copy updated based on the target dependency.
        ///
        /// This is where the magic happens that the host/host_features settings
        /// transition in a sticky fashion. As the dependency graph is being
        /// built, once those flags are set, they stay set for the duration of
        /// that portion of tree.
        pub fn with_dependency(
            self,
            parent: &Unit,
            dep_target: &Target,
            root_compile_kind: CompileKind,
        ) -> UnitFor {
            // A build script or proc-macro transitions this to being built for the host.
            let dep_for_host = dep_target.for_host();
            // This is where feature decoupling of host versus target happens.
            //
            // Once host features are desired, they are always desired.
            //
            // A proc-macro should always use host features.
            //
            // Dependencies of a build script should use host features (subtle
            // point: the build script itself does *not* use host features, that's
            // why the parent is checked here, and not the dependency).
            let host_features =
                self.host_features || parent.target.is_custom_build() || dep_target.proc_macro();
            // Build scripts and proc macros, and all of their dependencies are
            // AlwaysUnwind.
            let panic_setting = if dep_for_host {
                PanicSetting::AlwaysUnwind
            } else {
                self.panic_setting
            };
            UnitFor {
                host: self.host || dep_for_host,
                host_features,
                panic_setting,
                root_compile_kind,
                artifact_target_for_features: self.artifact_target_for_features,
            }
        }

        pub fn for_custom_build(self) -> UnitFor {
            UnitFor {
                host: true,
                host_features: self.host_features,
                // Force build scripts to always use `panic=unwind` for now to
                // maximally share dependencies with procedural macros.
                panic_setting: PanicSetting::AlwaysUnwind,
                root_compile_kind: self.root_compile_kind,
                artifact_target_for_features: self.artifact_target_for_features,
            }
        }

        /// Set the artifact compile target for use in features using the given `artifact`.
        pub(crate) fn with_artifact_features(mut self, artifact: &Artifact) -> UnitFor {
            self.artifact_target_for_features = artifact.target().and_then(|t| t.to_compile_target());
            self
        }

        /// Set the artifact compile target as determined by a resolved compile target. This is used if `target = "target"`.
        pub(crate) fn with_artifact_features_from_resolved_compile_kind(
            mut self,
            kind: Option<CompileKind>,
        ) -> UnitFor {
            self.artifact_target_for_features = kind.and_then(|kind| match kind {
                CompileKind::Host => None,
                CompileKind::Target(triple) => Some(triple),
            });
            self
        }

        /// Returns `true` if this unit is for a build script or any of its
        /// dependencies, or a proc macro or any of its dependencies.
        pub fn is_for_host(&self) -> bool {
            self.host
        }

        pub fn is_for_host_features(&self) -> bool {
            self.host_features
        }

        /// Returns how `panic` settings should be handled for this profile
        fn panic_setting(&self) -> PanicSetting {
            self.panic_setting
        }

        /// We might contain a parent artifact compile kind for features already, but will
        /// gladly accept the one of this dependency as an override as it defines how
        /// the artifact is built.
        /// If we are an artifact but don't specify a `target`, we assume the default
        /// compile kind that is suitable in this situation.
        pub(crate) fn map_to_features_for(&self, dep_artifact: Option<&Artifact>) -> FeaturesFor {
            FeaturesFor::from_for_host_or_artifact_target(
                self.is_for_host_features(),
                match dep_artifact {
                    Some(artifact) => artifact
                        .target()
                        .and_then(|t| t.to_resolved_compile_target(self.root_compile_kind)),
                    None => self.artifact_target_for_features,
                },
            )
        }

        pub(crate) fn root_compile_kind(&self) -> CompileKind {
            self.root_compile_kind
        }
    }

    /// Takes the manifest profiles, and overlays the config profiles on-top.
    ///
    /// Returns a new copy of the profile map with all the mergers complete.
    fn merge_config_profiles(
        ws: &Workspace<'_>,
        requested_profile: InternedString,
    ) -> CargoResult<BTreeMap<InternedString, TomlProfile>> {
        let mut profiles = match ws.profiles() {
            Some(profiles) => profiles
                .get_all()
                .iter()
                .map(|(k, v)| (InternedString::new(k), v.clone()))
                .collect(),
            None => BTreeMap::new(),
        };
        // Set of profile names to check if defined in config only.
        let mut check_to_add = HashSet::new();
        check_to_add.insert(requested_profile);
        // Merge config onto manifest profiles.
        for (name, profile) in &mut profiles {
            if let Some(config_profile) = get_config_profile(ws, name)? {
                profile.merge(&config_profile);
            }
            if let Some(inherits) = &profile.inherits {
                check_to_add.insert(InternedString::new(inherits));
            }
        }
        // Add the built-in profiles. This is important for things like `cargo
        // test` which implicitly use the "dev" profile for dependencies.
        for name in &["dev", "release", "test", "bench"] {
            check_to_add.insert(InternedString::new(name));
        }
        // Add config-only profiles.
        // Need to iterate repeatedly to get all the inherits values.
        let mut current = HashSet::new();
        while !check_to_add.is_empty() {
            std::mem::swap(&mut current, &mut check_to_add);
            for name in current.drain() {
                if !profiles.contains_key(name.as_str()) {
                    if let Some(config_profile) = get_config_profile(ws, &name)? {
                        if let Some(inherits) = &config_profile.inherits {
                            check_to_add.insert(InternedString::new(inherits));
                        }
                        profiles.insert(name, config_profile);
                    }
                }
            }
        }
        Ok(profiles)
    }

    /// Helper for fetching a profile from config.
    fn get_config_profile(ws: &Workspace<'_>, name: &str) -> CargoResult<Option<TomlProfile>> {
        let profile: Option<config::Value<TomlProfile>> =
            ws.config().get(&format!("profile.{}", name))?;
        let Some(profile) = profile else {
            return Ok(None);
        };
        let mut warnings = Vec::new();
        profile
            .val
            .validate(
                name,
                ws.config().cli_unstable(),
                ws.unstable_features(),
                &mut warnings,
            )
            .with_context(|| {
                format!(
                    "config profile `{}` is not valid (defined in `{}`)",
                    name, profile.definition
                )
            })?;
        for warning in warnings {
            ws.config().shell().warn(warning)?;
        }
        Ok(Some(profile.val))
    }

    /// Validate that a package does not match multiple package override specs.
    ///
    /// For example `[profile.dev.package.bar]` and `[profile.dev.package."bar:0.5.0"]`
    /// would both match `bar:0.5.0` which would be ambiguous.
    fn validate_packages_unique(
        resolve: &Resolve,
        name: &str,
        toml: &Option<TomlProfile>,
    ) -> CargoResult<HashSet<PackageIdSpec>> {
        let Some(toml) = toml else {
            return Ok(HashSet::new());
        };
        let Some(overrides) = toml.package.as_ref() else {
            return Ok(HashSet::new());
        };
        // Verify that a package doesn't match multiple spec overrides.
        let mut found = HashSet::new();
        for pkg_id in resolve.iter() {
            let matches: Vec<&PackageIdSpec> = overrides
                .keys()
                .filter_map(|key| match *key {
                    ProfilePackageSpec::All => None,
                    ProfilePackageSpec::Spec(ref spec) => {
                        if spec.matches(pkg_id) {
                            Some(spec)
                        } else {
                            None
                        }
                    }
                })
                .collect();
            match matches.len() {
                0 => {}
                1 => {
                    found.insert(matches[0].clone());
                }
                _ => {
                    let specs = matches
                        .iter()
                        .map(|spec| spec.to_string())
                        .collect::<Vec<_>>()
                        .join(", ");
                    bail!(
                        "multiple package overrides in profile `{}` match package `{}`\n\
                         found package specs: {}",
                        name,
                        pkg_id,
                        specs
                    );
                }
            }
        }
        Ok(found)
    }

    /// Check for any profile override specs that do not match any known packages.
    ///
    /// This helps check for typos and mistakes.
    fn validate_packages_unmatched(
        shell: &mut Shell,
        resolve: &Resolve,
        name: &str,
        toml: &TomlProfile,
        found: &HashSet<PackageIdSpec>,
    ) -> CargoResult<()> {
        let Some(overrides) = toml.package.as_ref() else {
            return Ok(());
        };

        // Verify every override matches at least one package.
        let missing_specs = overrides.keys().filter_map(|key| {
            if let ProfilePackageSpec::Spec(ref spec) = *key {
                if !found.contains(spec) {
                    return Some(spec);
                }
            }
            None
        });
        for spec in missing_specs {
            // See if there is an exact name match.
            let name_matches: Vec<String> = resolve
                .iter()
                .filter_map(|pkg_id| {
                    if pkg_id.name() == spec.name() {
                        Some(pkg_id.to_string())
                    } else {
                        None
                    }
                })
                .collect();
            if name_matches.is_empty() {
                let suggestion = closest_msg(&spec.name(), resolve.iter(), |p| p.name().as_str());
                shell.warn(format!(
                    "profile package spec `{}` in profile `{}` did not match any packages{}",
                    spec, name, suggestion
                ))?;
            } else {
                shell.warn(format!(
                    "profile package spec `{}` in profile `{}` \
                     has a version or URL that does not match any of the packages: {}",
                    spec,
                    name,
                    name_matches.join(", ")
                ))?;
            }
        }
        Ok(())
    }

    /// Returns `true` if a string is a toggle that turns an option off.
    fn is_off(s: &str) -> bool {
        matches!(s, "off" | "n" | "no" | "none")
    }