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    //! Definition of how to encode a `Resolve` into a TOML `Cargo.lock` file
    //!
    //! This module contains all machinery necessary to parse a `Resolve` from a
    //! `Cargo.lock` as well as serialize a `Resolve` to a `Cargo.lock`.
    //!
    //! ## Changing `Cargo.lock`
    //!
    //! In general Cargo is quite conservative about changing the format of
    //! `Cargo.lock`. Usage of new features in Cargo can change `Cargo.lock` at any
    //! time, but otherwise changing the serialization of `Cargo.lock` is a
    //! difficult operation to do that we typically avoid.
    //!
    //! The main problem with changing the format of `Cargo.lock` is that it can
    //! cause quite a bad experience for end users who use different versions of
    //! Cargo. If every PR to a project oscillates between the stable channel's
    //! encoding of Cargo.lock and the nightly channel's encoding then that's a
    //! pretty bad experience.
    //!
    //! We do, however, want to change `Cargo.lock` over time. (and we have!). To do
    //! this the rules that we currently have are:
    //!
    //! * Add support for the new format to Cargo. This involves code changes in
    //!   Cargo itself, likely by adding a new variant of `ResolveVersion` and
    //!   branching on that where necessary. This is accompanied with tests in the
    //!   `lockfile_compat` module.
    //!
    //!   * Do not update `ResolveVersion::default()`. The new lockfile format will
    //!     not be used yet.
    //!
    //!   * Preserve the new format if found. This means that if Cargo finds the new
    //!     version it'll keep using it, but otherwise it continues to use whatever
    //!     format it previously found.
    //!
    //! * Wait a "long time". This is at least until the changes here hit stable
    //!   Rust. Often though we wait a little longer to let the changes percolate
    //!   into one or two older stable releases.
    //!
    //! * Change the return value of `ResolveVersion::default()` to the new format.
    //!   This will cause new lock files to use the latest encoding as well as
    //!   causing any operation which updates the lock file to update to the new
    //!   format.
    //!
    //! This migration scheme in general means that Cargo we'll get *support* for a
    //! new format into Cargo ASAP, but it won't be exercised yet (except in Cargo's
    //! own tests). Eventually when stable/beta/nightly all have support for the new
    //! format (and maybe a few previous stable versions) we flip the switch.
    //! Projects on nightly will quickly start seeing changes, but
    //! stable/beta/nightly will all understand this new format and will preserve
    //! it.
    //!
    //! While this does mean that projects' `Cargo.lock` changes over time, it's
    //! typically a pretty minimal effort change that's just "check in what's
    //! there".
    //!
    //! ## Historical changes to `Cargo.lock`
    //!
    //! Listed from most recent to oldest, these are some of the changes we've made
    //! to `Cargo.lock`'s serialization format:
    //!
    //! * A `version` marker is now at the top of the lock file which is a way for
    //!   super-old Cargos (at least since this was implemented) to give a formal
    //!   error if they see a lock file from a super-future Cargo. Additionally as
    //!   part of this change the encoding of `git` dependencies in lock files
    //!   changed where `branch = "master"` is now encoded with `branch=master`
    //!   instead of with nothing at all.
    //!
    //! * The entries in `dependencies` arrays have been shortened and the
    //!   `checksum` field now shows up directly in `[[package]]` instead of always
    //!   at the end of the file. The goal of this change was to ideally reduce
    //!   merge conflicts being generated on `Cargo.lock`. Updating a version of a
    //!   package now only updates two lines in the file, the checksum and the
    //!   version number, most of the time. Dependency edges are specified in a
    //!   compact form where possible where just the name is listed. The
    //!   version/source on dependency edges are only listed if necessary to
    //!   disambiguate which version or which source is in use.
    //!
    //! * A comment at the top of the file indicates that the file is a generated
    //!   file and contains the special symbol `@generated` to indicate to common
    //!   review tools that it's a generated file.
    //!
    //! * A `[root]` entry for the "root crate" has been removed and instead now
    //!   included in `[[package]]` like everything else.
    //!
    //! * All packages from registries contain a `checksum` which is a sha256
    //!   checksum of the tarball the package is associated with. This is all stored
    //!   in the `[metadata]` table of `Cargo.lock` which all versions of Cargo
    //!   since 1.0 have preserved. The goal of this was to start recording
    //!   checksums so mirror sources can be verified.
    //!
    //! ## Other oddities about `Cargo.lock`
    //!
    //! There's a few other miscellaneous weird things about `Cargo.lock` that you
    //! may want to be aware of when reading this file:
    //!
    //! * All packages have a `source` listed to indicate where they come from. For
    //!   `path` dependencies, however, no `source` is listed. There's no way we
    //!   could emit a filesystem path name and have that be portable across
    //!   systems, so all packages from a `path` are not listed with a `source`.
    //!   Note that this also means that all packages with `path` sources must have
    //!   unique names.
    //!
    //! * The `[metadata]` table in `Cargo.lock` is intended to be a generic mapping
    //!   of strings to strings that's simply preserved by Cargo. This was a very
    //!   early effort to be forward compatible against changes to `Cargo.lock`'s
    //!   format. This is nowadays sort of deemed a bad idea though and we don't
    //!   really use it that much except for `checksum`s historically. It's not
    //!   really recommended to use this.
    //!
    //! * The actual literal on-disk serialiation is found in
    //!   `src/cargo/ops/lockfile.rs` which basically renders a `toml::Value` in a
    //!   special fashion to make sure we have strict control over the on-disk
    //!   format.

    use super::{Resolve, ResolveVersion};
    use crate::core::{Dependency, GitReference, Package, PackageId, SourceId, Workspace};
    use crate::util::errors::CargoResult;
    use crate::util::interning::InternedString;
    use crate::util::{internal, Graph};
    use anyhow::{bail, Context as _};
    use serde::de;
    use serde::ser;
    use serde::{Deserialize, Serialize};
    use std::collections::{BTreeMap, HashMap, HashSet};
    use std::fmt;
    use std::str::FromStr;
    use tracing::debug;

    /// The `Cargo.lock` structure.
    #[derive(Serialize, Deserialize, Debug)]
    pub struct EncodableResolve {
        version: Option<u32>,
        package: Option<Vec<EncodableDependency>>,
        /// `root` is optional to allow backward compatibility.
        root: Option<EncodableDependency>,
        metadata: Option<Metadata>,
        #[serde(default, skip_serializing_if = "Patch::is_empty")]
        patch: Patch,
    }

    #[derive(Serialize, Deserialize, Debug, Default)]
    struct Patch {
        unused: Vec<EncodableDependency>,
    }

    pub type Metadata = BTreeMap<String, String>;

    impl EncodableResolve {
        /// Convert a `Cargo.lock` to a Resolve.
        ///
        /// Note that this `Resolve` is not "complete". For example, the
        /// dependencies do not know the difference between regular/dev/build
        /// dependencies, so they are not filled in. It also does not include
        /// `features`. Care should be taken when using this Resolve. One of the
        /// primary uses is to be used with `resolve_with_previous` to guide the
        /// resolver to create a complete Resolve.
        pub fn into_resolve(self, original: &str, ws: &Workspace<'_>) -> CargoResult<Resolve> {
            let path_deps = build_path_deps(ws)?;
            let mut checksums = HashMap::new();

            let mut version = match self.version {
                Some(n @ 5) if ws.gctx().nightly_features_allowed => {
                    if ws.gctx().cli_unstable().next_lockfile_bump {
                        ResolveVersion::V5
                    } else {
                        anyhow::bail!("lock file version `{n}` requires `-Znext-lockfile-bump`");
                    }
                }
                Some(4) => ResolveVersion::V4,
                Some(3) => ResolveVersion::V3,
                Some(n) => bail!(
                    "lock file version `{}` was found, but this version of Cargo \
                     does not understand this lock file, perhaps Cargo needs \
                     to be updated?",
                    n,
                ),
                // Historically Cargo did not have a version indicator in lock
                // files, so this could either be the V1 or V2 encoding. We assume
                // an older format is being parsed until we see so otherwise.
                None => ResolveVersion::V1,
            };

            let packages = {
                let mut packages = self.package.unwrap_or_default();
                if let Some(root) = self.root {
                    packages.insert(0, root);
                }
                packages
            };

            // `PackageId`s in the lock file don't include the `source` part
            // for workspace members, so we reconstruct proper IDs.
            let live_pkgs = {
                let mut live_pkgs = HashMap::new();
                let mut all_pkgs = HashSet::new();
                for pkg in packages.iter() {
                    let enc_id = EncodablePackageId {
                        name: pkg.name.clone(),
                        version: Some(pkg.version.clone()),
                        source: pkg.source.clone(),
                    };

                    if !all_pkgs.insert(enc_id.clone()) {
                        anyhow::bail!("package `{}` is specified twice in the lockfile", pkg.name);
                    }
                    let id = match pkg.source.as_deref().or_else(|| path_deps.get(&pkg.name)) {
                        // We failed to find a local package in the workspace.
                        // It must have been removed and should be ignored.
                        None => {
                            debug!("path dependency now missing {} v{}", pkg.name, pkg.version);
                            continue;
                        }
                        Some(&source) => PackageId::try_new(&pkg.name, &pkg.version, source)?,
                    };

                    // If a package has a checksum listed directly on it then record
                    // that here, and we also bump our version up to 2 since V1
                    // didn't ever encode this field.
                    if let Some(cksum) = &pkg.checksum {
                        version = version.max(ResolveVersion::V2);
                        checksums.insert(id, Some(cksum.clone()));
                    }

                    assert!(live_pkgs.insert(enc_id, (id, pkg)).is_none())
                }
                live_pkgs
            };

            // When decoding a V2 version the edges in `dependencies` aren't
            // guaranteed to have either version or source information. This `map`
            // is used to find package ids even if dependencies have missing
            // information. This map is from name to version to source to actual
            // package ID. (various levels to drill down step by step)
            let mut map = HashMap::new();
            for (id, _) in live_pkgs.values() {
                map.entry(id.name().as_str())
                    .or_insert_with(HashMap::new)
                    .entry(id.version().to_string())
                    .or_insert_with(HashMap::new)
                    .insert(id.source_id(), *id);
            }

            let mut lookup_id = |enc_id: &EncodablePackageId| -> Option<PackageId> {
                // The name of this package should always be in the larger list of
                // all packages.
                let by_version = map.get(enc_id.name.as_str())?;

                // If the version is provided, look that up. Otherwise if the
                // version isn't provided this is a V2 manifest and we should only
                // have one version for this name. If we have more than one version
                // for the name then it's ambiguous which one we'd use. That
                // shouldn't ever actually happen but in theory bad git merges could
                // produce invalid lock files, so silently ignore these cases.
                let by_source = match &enc_id.version {
                    Some(version) => by_version.get(version)?,
                    None => {
                        version = version.max(ResolveVersion::V2);
                        if by_version.len() == 1 {
                            by_version.values().next().unwrap()
                        } else {
                            return None;
                        }
                    }
                };

                // This is basically the same as above. Note though that `source` is
                // always missing for path dependencies regardless of serialization
                // format. That means we have to handle the `None` case a bit more
                // carefully.
                match &enc_id.source {
                    Some(source) => by_source.get(source).cloned(),
                    None => {
                        // Look through all possible packages ids for this
                        // name/version. If there's only one `path` dependency then
                        // we are hardcoded to use that since `path` dependencies
                        // can't have a source listed.
                        let mut path_packages = by_source.values().filter(|p| p.source_id().is_path());
                        if let Some(path) = path_packages.next() {
                            if path_packages.next().is_some() {
                                return None;
                            }
                            Some(*path)

                        // ... otherwise if there's only one then we must be
                        // implicitly using that one due to a V2 serialization of
                        // the lock file
                        } else if by_source.len() == 1 {
                            let id = by_source.values().next().unwrap();
                            version = version.max(ResolveVersion::V2);
                            Some(*id)

                        // ... and failing that we probably had a bad git merge of
                        // `Cargo.lock` or something like that, so just ignore this.
                        } else {
                            None
                        }
                    }
                }
            };

            let mut g = Graph::new();

            for (id, _) in live_pkgs.values() {
                g.add(*id);
            }

            for &(ref id, pkg) in live_pkgs.values() {
                let Some(ref deps) = pkg.dependencies else {
                    continue;
                };

                for edge in deps.iter() {
                    if let Some(to_depend_on) = lookup_id(edge) {
                        g.link(*id, to_depend_on);
                    }
                }
            }

            let replacements = {
                let mut replacements = HashMap::new();
                for &(ref id, pkg) in live_pkgs.values() {
                    if let Some(ref replace) = pkg.replace {
                        assert!(pkg.dependencies.is_none());
                        if let Some(replace_id) = lookup_id(replace) {
                            replacements.insert(*id, replace_id);
                        }
                    }
                }
                replacements
            };

            let mut metadata = self.metadata.unwrap_or_default();

            // In the V1 serialization formats all checksums were listed in the lock
            // file in the `[metadata]` section, so if we're still V1 then look for
            // that here.
            let prefix = "checksum ";
            let mut to_remove = Vec::new();
            for (k, v) in metadata.iter().filter(|p| p.0.starts_with(prefix)) {
                to_remove.push(k.to_string());
                let k = k.strip_prefix(prefix).unwrap();
                let enc_id: EncodablePackageId = k
                    .parse()
                    .with_context(|| internal("invalid encoding of checksum in lockfile"))?;
                let Some(id) = lookup_id(&enc_id) else {
                    continue;
                };

                let v = if v == "<none>" {
                    None
                } else {
                    Some(v.to_string())
                };
                checksums.insert(id, v);
            }
            // If `checksum` was listed in `[metadata]` but we were previously
            // listed as `V2` then assume some sort of bad git merge happened, so
            // discard all checksums and let's regenerate them later.
            if !to_remove.is_empty() && version >= ResolveVersion::V2 {
                checksums.drain();
            }
            for k in to_remove {
                metadata.remove(&k);
            }

            let mut unused_patches = Vec::new();
            for pkg in self.patch.unused {
                let id = match pkg.source.as_deref().or_else(|| path_deps.get(&pkg.name)) {
                    Some(&src) => PackageId::try_new(&pkg.name, &pkg.version, src)?,
                    None => continue,
                };
                unused_patches.push(id);
            }

            // We have a curious issue where in the "v1 format" we buggily had a
            // trailing blank line at the end of lock files under some specific
            // conditions.
            //
            // Cargo is trying to write new lockfies in the "v2 format" but if you
            // have no dependencies, for example, then the lockfile encoded won't
            // really have any indicator that it's in the new format (no
            // dependencies or checksums listed). This means that if you type `cargo
            // new` followed by `cargo build` it will generate a "v2 format" lock
            // file since none previously existed. When reading this on the next
            // `cargo build`, however, it generates a new lock file because when
            // reading in that lockfile we think it's the v1 format.
            //
            // To help fix this issue we special case here. If our lockfile only has
            // one trailing newline, not two, *and* it only has one package, then
            // this is actually the v2 format.
            if original.ends_with('\n')
                && !original.ends_with("\n\n")
                && version == ResolveVersion::V1
                && g.iter().count() == 1
            {
                version = ResolveVersion::V2;
            }

            Ok(Resolve::new(
                g,
                replacements,
                HashMap::new(),
                checksums,
                metadata,
                unused_patches,
                version,
                HashMap::new(),
            ))
        }
    }

    fn build_path_deps(ws: &Workspace<'_>) -> CargoResult<HashMap<String, SourceId>> {
        // If a crate is **not** a path source, then we're probably in a situation
        // such as `cargo install` with a lock file from a remote dependency. In
        // that case we don't need to fixup any path dependencies (as they're not
        // actually path dependencies any more), so we ignore them.
        let members = ws
            .members()
            .filter(|p| p.package_id().source_id().is_path())
            .collect::<Vec<_>>();

        let mut ret = HashMap::new();
        let mut visited = HashSet::new();
        for member in members.iter() {
            ret.insert(
                member.package_id().name().to_string(),
                member.package_id().source_id(),
            );
            visited.insert(member.package_id().source_id());
        }
        for member in members.iter() {
            build_pkg(member, ws, &mut ret, &mut visited);
        }
        for deps in ws.root_patch()?.values() {
            for dep in deps {
                build_dep(dep, ws, &mut ret, &mut visited);
            }
        }
        for (_, dep) in ws.root_replace() {
            build_dep(dep, ws, &mut ret, &mut visited);
        }

        return Ok(ret);

        fn build_pkg(
            pkg: &Package,
            ws: &Workspace<'_>,
            ret: &mut HashMap<String, SourceId>,
            visited: &mut HashSet<SourceId>,
        ) {
            for dep in pkg.dependencies() {
                build_dep(dep, ws, ret, visited);
            }
        }

        fn build_dep(
            dep: &Dependency,
            ws: &Workspace<'_>,
            ret: &mut HashMap<String, SourceId>,
            visited: &mut HashSet<SourceId>,
        ) {
            let id = dep.source_id();
            if visited.contains(&id) || !id.is_path() {
                return;
            }
            let path = match id.url().to_file_path() {
                Ok(p) => p.join("Cargo.toml"),
                Err(_) => return,
            };
            let Ok(pkg) = ws.load(&path) else { return };
            ret.insert(pkg.name().to_string(), pkg.package_id().source_id());
            visited.insert(pkg.package_id().source_id());
            build_pkg(&pkg, ws, ret, visited);
        }
    }

    impl Patch {
        fn is_empty(&self) -> bool {
            self.unused.is_empty()
        }
    }

    #[derive(Serialize, Deserialize, Debug, PartialOrd, Ord, PartialEq, Eq)]
    pub struct EncodableDependency {
        name: String,
        version: String,
        source: Option<EncodableSourceId>,
        checksum: Option<String>,
        dependencies: Option<Vec<EncodablePackageId>>,
        replace: Option<EncodablePackageId>,
    }

    /// Pretty much equivalent to [`SourceId`] with a different serialization method.
    ///
    /// The serialization for `SourceId` doesn't do URL encode for parameters.
    /// In contrast, this type is aware of that whenever [`ResolveVersion`] allows
    /// us to do so (v4 or later).
    ///
    /// [`EncodableResolve`] turns into a `
    #[derive(Deserialize, Debug, PartialOrd, Ord, Clone)]
    #[serde(transparent)]
    pub struct EncodableSourceId {
        inner: SourceId,
        /// We don't care about the deserialization of this, as the `url` crate
        /// will always decode as the URL was encoded. Only when a [`Resolve`]
        /// turns into a [`EncodableResolve`] will it set the value accordingly
        /// via [`encodable_source_id`].
        #[serde(skip)]
        encoded: bool,
    }

    impl EncodableSourceId {
        /// Creates a `EncodableSourceId` that always encodes URL params.
        fn new(inner: SourceId) -> Self {
            Self {
                inner,
                encoded: true,
            }
        }

        /// Creates a `EncodableSourceId` that doesn't encode URL params. This is
        /// for backward compatibility for order lockfile version.
        fn without_url_encoded(inner: SourceId) -> Self {
            Self {
                inner,
                encoded: false,
            }
        }

        /// Encodes the inner [`SourceId`] as a URL.
        fn as_url(&self) -> impl fmt::Display + '_ {
            if self.encoded {
                self.inner.as_encoded_url()
            } else {
                self.inner.as_url()
            }
        }
    }

    impl std::ops::Deref for EncodableSourceId {
        type Target = SourceId;

        fn deref(&self) -> &Self::Target {
            &self.inner
        }
    }

    impl ser::Serialize for EncodableSourceId {
        fn serialize<S>(&self, s: S) -> Result<S::Ok, S::Error>
        where
            S: ser::Serializer,
        {
            s.collect_str(&self.as_url())
        }
    }

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

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

    impl std::cmp::Eq for EncodableSourceId {}

    #[derive(Debug, PartialOrd, Ord, PartialEq, Eq, Hash, Clone)]
    pub struct EncodablePackageId {
        name: String,
        version: Option<String>,
        source: Option<EncodableSourceId>,
    }

    impl fmt::Display for EncodablePackageId {
        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
            write!(f, "{}", self.name)?;
            if let Some(s) = &self.version {
                write!(f, " {}", s)?;
            }
            if let Some(s) = &self.source {
                write!(f, " ({})", s.as_url())?;
            }
            Ok(())
        }
    }

    impl FromStr for EncodablePackageId {
        type Err = anyhow::Error;

        fn from_str(s: &str) -> CargoResult<EncodablePackageId> {
            let mut s = s.splitn(3, ' ');
            let name = s.next().unwrap();
            let version = s.next();
            let source_id = match s.next() {
                Some(s) => {
                    if let Some(s) = s.strip_prefix('(').and_then(|s| s.strip_suffix(')')) {
                        Some(SourceId::from_url(s)?)
                    } else {
                        anyhow::bail!("invalid serialized PackageId")
                    }
                }
                None => None,
            };

            Ok(EncodablePackageId {
                name: name.to_string(),
                version: version.map(|v| v.to_string()),
                // Default to url encoded.
                source: source_id.map(EncodableSourceId::new),
            })
        }
    }

    impl ser::Serialize for EncodablePackageId {
        fn serialize<S>(&self, s: S) -> Result<S::Ok, S::Error>
        where
            S: ser::Serializer,
        {
            s.collect_str(self)
        }
    }

    impl<'de> de::Deserialize<'de> for EncodablePackageId {
        fn deserialize<D>(d: D) -> Result<EncodablePackageId, D::Error>
        where
            D: de::Deserializer<'de>,
        {
            String::deserialize(d).and_then(|string| {
                string
                    .parse::<EncodablePackageId>()
                    .map_err(de::Error::custom)
            })
        }
    }

    impl ser::Serialize for Resolve {
        #[tracing::instrument(skip_all)]
        fn serialize<S>(&self, s: S) -> Result<S::Ok, S::Error>
        where
            S: ser::Serializer,
        {
            let mut ids: Vec<_> = self.iter().collect();
            ids.sort();

            let state = EncodeState::new(self);

            let encodable = ids
                .iter()
                .map(|&id| encodable_resolve_node(id, self, &state))
                .collect::<Vec<_>>();

            let mut metadata = self.metadata().clone();

            if self.version() == ResolveVersion::V1 {
                for &id in ids.iter().filter(|id| !id.source_id().is_path()) {
                    let checksum = match self.checksums()[&id] {
                        Some(ref s) => &s[..],
                        None => "<none>",
                    };
                    let id = encodable_package_id(id, &state, self.version());
                    metadata.insert(format!("checksum {}", id.to_string()), checksum.to_string());
                }
            }

            let metadata = if metadata.is_empty() {
                None
            } else {
                Some(metadata)
            };

            let patch = Patch {
                unused: self
                    .unused_patches()
                    .iter()
                    .map(|id| EncodableDependency {
                        name: id.name().to_string(),
                        version: id.version().to_string(),
                        source: encodable_source_id(id.source_id(), self.version()),
                        dependencies: None,
                        replace: None,
                        checksum: if self.version() >= ResolveVersion::V2 {
                            self.checksums().get(id).and_then(|x| x.clone())
                        } else {
                            None
                        },
                    })
                    .collect(),
            };
            EncodableResolve {
                package: Some(encodable),
                root: None,
                metadata,
                patch,
                version: match self.version() {
                    ResolveVersion::V5 => Some(5),
                    ResolveVersion::V4 => Some(4),
                    ResolveVersion::V3 => Some(3),
                    ResolveVersion::V2 | ResolveVersion::V1 => None,
                },
            }
            .serialize(s)
        }
    }

    pub struct EncodeState<'a> {
        counts: Option<HashMap<InternedString, HashMap<&'a semver::Version, usize>>>,
    }

    impl<'a> EncodeState<'a> {
        pub fn new(resolve: &'a Resolve) -> EncodeState<'a> {
            let counts = if resolve.version() >= ResolveVersion::V2 {
                let mut map = HashMap::new();
                for id in resolve.iter() {
                    let slot = map
                        .entry(id.name())
                        .or_insert_with(HashMap::new)
                        .entry(id.version())
                        .or_insert(0);
                    *slot += 1;
                }
                Some(map)
            } else {
                None
            };
            EncodeState { counts }
        }
    }

    fn encodable_resolve_node(
        id: PackageId,
        resolve: &Resolve,
        state: &EncodeState<'_>,
    ) -> EncodableDependency {
        let (replace, deps) = match resolve.replacement(id) {
            Some(id) => (
                Some(encodable_package_id(id, state, resolve.version())),
                None,
            ),
            None => {
                let mut deps = resolve
                    .deps_not_replaced(id)
                    .map(|(id, _)| encodable_package_id(id, state, resolve.version()))
                    .collect::<Vec<_>>();
                deps.sort();
                (None, Some(deps))
            }
        };

        EncodableDependency {
            name: id.name().to_string(),
            version: id.version().to_string(),
            source: encodable_source_id(id.source_id(), resolve.version()),
            dependencies: deps,
            replace,
            checksum: if resolve.version() >= ResolveVersion::V2 {
                resolve.checksums().get(&id).and_then(|s| s.clone())
            } else {
                None
            },
        }
    }

    pub fn encodable_package_id(
        id: PackageId,
        state: &EncodeState<'_>,
        resolve_version: ResolveVersion,
    ) -> EncodablePackageId {
        let mut version = Some(id.version().to_string());
        let mut id_to_encode = id.source_id();
        if resolve_version <= ResolveVersion::V2 {
            if let Some(GitReference::Branch(b)) = id_to_encode.git_reference() {
                if b == "master" {
                    id_to_encode =
                        SourceId::for_git(id_to_encode.url(), GitReference::DefaultBranch).unwrap();
                }
            }
        }
        let mut source = encodable_source_id(id_to_encode.without_precise(), resolve_version);
        if let Some(counts) = &state.counts {
            let version_counts = &counts[&id.name()];
            if version_counts[&id.version()] == 1 {
                source = None;
                if version_counts.len() == 1 {
                    version = None;
                }
            }
        }
        EncodablePackageId {
            name: id.name().to_string(),
            version,
            source,
        }
    }

    fn encodable_source_id(id: SourceId, version: ResolveVersion) -> Option<EncodableSourceId> {
        if id.is_path() {
            None
        } else {
            Some(if version >= ResolveVersion::V4 {
                EncodableSourceId::new(id)
            } else {
                EncodableSourceId::without_url_encoded(id)
            })
        }
    }