crate_universe: synthesize build-script edge at render time

A library/binary/proc-macro built from a crate with a build script depends
on that crate's own build_script_build target. That edge was recorded as a
self-referential entry in common_attrs.deps, which also feeds
workspace_member_deps() and produced a spurious crate-hub alias for any
workspace member that is a library with a build script (issue #4089).

Stop recording the self-edge in common_attrs.deps (reserved for cross-crate
deps) and instead synthesize the build_script_build edge during rendering
from the presence of the build-script target. workspace_member_deps() then
naturally excludes it with no filtering.

Upstream issue: #4089

Author: ashi009

crate_universe/src/context.rs

@@ -406,13 +406,16 @@ mod test {
         let context = mock_context_workspace_build_scripts_deps();
         let workspace_member_deps = context.workspace_member_deps();
 
+        // `child` is a workspace member with a build script. Its library's edge
+        // to its own `build_script_build` target is not a cross-crate dependency
+        // and is no longer recorded in `common_attrs.deps`, so only the build
+        // script's own deps (`tonic`/`tonic-build`) are collected here.
         assert_eq! {
             workspace_member_deps
                 .iter()
                 .map(|dep| (&dep.id, context.has_duplicate_workspace_member_dep_by_alias(dep)))
                 .collect::<Vec<_>>(),
             [
-                (&CrateId::new("child".to_owned(), Version::new(0, 1, 0)), false),
                 (&CrateId::new("tonic".to_owned(), Version::new(0, 4, 3)), false),
                 (&CrateId::new("tonic-build".to_owned(), Version::new(0, 4, 2)), false),
             ],

crate_universe/src/context/crate_context.rs

@@ -431,7 +431,7 @@ impl CrateContext {
             .unwrap_or_default();
 
         // Gather all "common" attributes
-        let mut common_attrs = CommonAttributes {
+        let common_attrs = CommonAttributes {
             crate_features,
             deps,
             deps_dev,
@@ -494,21 +494,13 @@ impl CrateContext {
             _ => None,
         });
 
-        let build_script_attrs = if let Some(target) = build_script_target {
-            // Track the build script dependency
-            common_attrs.deps.insert(
-                CrateDependency {
-                    id: current_crate_id,
-                    target: target.crate_name.clone(),
-                    alias: None,
-                    local_path: match source_annotations.get(&annotation.node.id) {
-                        Some(SourceAnnotation::Path { path }) => Some(path.clone()),
-                        _ => None,
-                    },
-                },
-                None,
-            );
-
+        let build_script_attrs = if build_script_target.is_some() {
+            // A library/binary/proc-macro built from this crate depends on its
+            // own build script; that edge is synthesized at render time from the
+            // presence of the build-script target (see Renderer). It is
+            // deliberately not recorded as a self-referential entry in
+            // `common_attrs.deps`, which is reserved for cross-crate
+            // dependencies and feeds workspace-member alias generation.
             let build_deps = annotation.deps.build_deps.clone().map(new_crate_dep);
             let build_link_deps = annotation.deps.build_link_deps.clone().map(new_crate_dep);
             let build_proc_macro_deps = annotation

crate_universe/src/rendering.rs

@@ -682,13 +682,7 @@ impl Renderer {
     ) -> Result<RustProcMacro> {
         Ok(RustProcMacro {
             name: target.crate_name.clone(),
-            deps: SelectSet::new(
-                self.make_deps(
-                    krate.common_attrs.deps.clone(),
-                    krate.common_attrs.extra_deps.clone(),
-                ),
-                platforms,
-            ),
+            deps: SelectSet::new(self.make_target_deps(krate), platforms),
             proc_macro_deps: SelectSet::new(
                 self.make_deps(
                     krate.common_attrs.proc_macro_deps.clone(),
@@ -709,13 +703,7 @@ impl Renderer {
     ) -> Result<RustLibrary> {
         Ok(RustLibrary {
             name: target.crate_name.clone(),
-            deps: SelectSet::new(
-                self.make_deps(
-                    krate.common_attrs.deps.clone(),
-                    krate.common_attrs.extra_deps.clone(),
-                ),
-                platforms,
-            ),
+            deps: SelectSet::new(self.make_target_deps(krate), platforms),
             proc_macro_deps: SelectSet::new(
                 self.make_deps(
                     krate.common_attrs.proc_macro_deps.clone(),
@@ -742,10 +730,7 @@ impl Renderer {
             .iter()
             .any(|rule| matches!(rule, Rule::ProcMacro(_)));
 
-        let mut deps = self.make_deps(
-            krate.common_attrs.deps.clone(),
-            krate.common_attrs.extra_deps.clone(),
-        );
+        let mut deps = self.make_target_deps(krate);
         let mut proc_macro_deps = self.make_deps(
             krate.common_attrs.proc_macro_deps.clone(),
             krate.common_attrs.extra_proc_macro_deps.clone(),
@@ -870,6 +855,40 @@ impl Renderer {
         aliases
     }
 
+    /// Render the `deps` for a crate's library/binary/proc-macro target,
+    /// including an edge to the crate's own build script when one is present. A
+    /// crate with a build script depends on its `build_script_build` target for
+    /// the script's generated outputs. This edge is synthesized here rather than
+    /// recorded as a self-referential entry in `common_attrs.deps`, which is
+    /// reserved for cross-crate dependencies.
+    fn make_target_deps(&self, krate: &CrateContext) -> Select<BTreeSet<Label>> {
+        let mut deps = self.make_deps(
+            krate.common_attrs.deps.clone(),
+            krate.common_attrs.extra_deps.clone(),
+        );
+        if let Some(label) = self.build_script_label(krate) {
+            deps.insert(label, None);
+        }
+        deps
+    }
+
+    /// The label of a crate's own build script target, if it defines one.
+    fn build_script_label(&self, krate: &CrateContext) -> Option<Label> {
+        let build_script_name = krate.targets.iter().find_map(|target| match target {
+            Rule::BuildScript(attrs) => Some(&attrs.crate_name),
+            _ => None,
+        })?;
+        let label = match (&krate.repository, self.config.vendor_mode) {
+            // In local vendor mode, we use paths within the repo.
+            (Some(SourceAnnotation::Path { path }), Some(VendorMode::Local)) => {
+                Label::from_str(&format!("//{}:{}", path, build_script_name)).unwrap()
+            }
+            // Otherwise construct the label of the crate's own build script.
+            _ => self.crate_label(&krate.name, &krate.version.to_string(), build_script_name),
+        };
+        Some(label)
+    }
+
     fn make_deps(
         &self,
         deps: Select<BTreeSet<CrateDependency>>,