Consider public dependencies when choosing a version in cargo add (#1…

src/cargo/ops/cargo_add/mod.rs

@@ -20,6 +20,7 @@ use toml_edit::Item as TomlItem;
 
 use crate::CargoResult;
 use crate::GlobalContext;
+use crate::core::Feature;
 use crate::core::FeatureValue;
 use crate::core::Features;
 use crate::core::Package;
@@ -29,6 +30,7 @@ use crate::core::Summary;
 use crate::core::Workspace;
 use crate::core::dependency::DepKind;
 use crate::core::registry::PackageRegistry;
+use crate::ops::resolve_ws;
 use crate::sources::source::QueryKind;
 use crate::util::cache_lock::CacheLockMode;
 use crate::util::edit_distance;
@@ -38,6 +40,7 @@ use crate::util::toml_mut::dependency::Dependency;
 use crate::util::toml_mut::dependency::GitSource;
 use crate::util::toml_mut::dependency::MaybeWorkspace;
 use crate::util::toml_mut::dependency::PathSource;
+use crate::util::toml_mut::dependency::RegistrySource;
 use crate::util::toml_mut::dependency::Source;
 use crate::util::toml_mut::dependency::WorkspaceSource;
 use crate::util::toml_mut::manifest::DepTable;
@@ -471,6 +474,13 @@ fn resolve_dependency(
                 src = src.set_version(v);
             }
             dependency = dependency.set_source(src);
+        } else if let Some((registry, public_source)) =
+            get_public_dependency(spec, manifest, ws, section, gctx, &dependency)?
+        {
+            if let Some(registry) = registry {
+                dependency = dependency.set_registry(registry);
+            }
+            dependency = dependency.set_source(public_source);
         } else {
             let latest =
                 get_latest_dependency(spec, &dependency, honor_rust_version, gctx, registry)?;
@@ -507,11 +517,107 @@ fn resolve_dependency(
     Ok(dependency)
 }
 
+fn get_public_dependency(
+    spec: &Package,
+    manifest: &LocalManifest,
+    ws: &Workspace<'_>,
+    section: &DepTable,
+    gctx: &GlobalContext,
+    dependency: &Dependency,
+) -> CargoResult<Option<(Option<String>, Source)>> {
+    if spec
+        .manifest()
+        .unstable_features()
+        .require(Feature::public_dependency())
+        .is_err()
+    {
+        return Ok(None);
+    }
+
+    let (package_set, resolve) = resolve_ws(ws, true)?;
+
+    let mut latest = None;
+
+    for (_, path, dep) in manifest.get_dependencies(ws, ws.unstable_features()) {
+        if path != *section {
+            continue;
+        }
+
+        let Some(mut dep) = dep.ok() else {
+            continue;
+        };
+
+        let dep = query_dependency(ws, gctx, &mut dep)?;
+        let Some(dep_pkgid) = package_set
+            .package_ids()
+            .filter(|package_id| {
+                package_id.name() == dep.package_name()
+                    && dep.version_req().matches(package_id.version())
+            })
+            .max_by_key(|x| x.version())
+        else {
+            continue;
+        };
+
+        let pkg_ids_and_reqs = resolve.deps(dep_pkgid).filter_map(|(id, deps)| {
+            deps.iter()
+                .find(|dep| {
+                    dep.is_public()
+                        && dep.kind() == DepKind::Normal
+                        && dep.package_name() == dependency.name.as_str()
+                })
+                .map(|dep| (id, dep.version_req().clone()))
+        });
+
+        for (pkg_id, req) in pkg_ids_and_reqs {
+            if let Some((old_pkg_id, _)) = &latest
+                && *old_pkg_id >= pkg_id
+            {
+                continue;
+            }
+            latest = Some((pkg_id, req))
+        }
+    }
+
+    let Some((pkg_id, version_req)) = latest else {
+        return Ok(None);
+    };
+
+    let source = pkg_id.source_id();
+    if source.is_git() {
+        Ok(Some((
+            Option::<String>::None,
+            Source::Git(GitSource::new(source.as_encoded_url().to_string())),
+        )))
+    } else if let Some(path) = source.local_path() {
+        Ok(Some((None, Source::Path(PathSource::new(path)))))
+    } else {
+        let toml_source = match version_req {
+            crate::util::OptVersionReq::Any => Source::Registry(RegistrySource::new(format!(
+                "={}",
+                pkg_id.version().to_string()
+            ))),
+            crate::util::OptVersionReq::Req(version_req)
+            | crate::util::OptVersionReq::Locked(_, version_req)
+            | crate::util::OptVersionReq::Precise(_, version_req) => {
+                Source::Registry(RegistrySource::new(version_req.to_string()))
+            }
+        };
+        Ok(Some((
+            source
+                .alt_registry_key()
+                .map(|x| x.to_owned())
+                .filter(|_| !source.is_crates_io()),
+            toml_source,
+        )))
+    }
+}
+
 fn query_dependency(
     ws: &Workspace<'_>,
     gctx: &GlobalContext,
     dependency: &mut Dependency,
-) -> Result<crate::core::Dependency, anyhow::Error> {
+) -> CargoResult<crate::core::Dependency> {
     let query = dependency.query(gctx)?;
     let query = match query {
         MaybeWorkspace::Workspace(_workspace) => {

tests/testsuite/cargo_add/public_common_version/out/Cargo.toml

@@ -8,4 +8,4 @@ edition = "2015"
 
 [dependencies]
 my-package = "0.1.0"
-my-package-dep = "0.2.0"
+my-package-dep = "^0.1.0"