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

@@ -412,7 +412,6 @@ mod test {
                 .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

@@ -115,6 +115,11 @@ pub(crate) struct CommonAttributes {
     #[serde(skip_serializing_if = "Select::is_empty")]
     pub(crate) deps: Select<BTreeSet<CrateDependency>>,
 
+    /// The crate's own build script, which its library/binary/proc-macro targets
+    /// depend on for the script's generated outputs.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(crate) build_script_dep: Option<CrateDependency>,
+
     #[serde(skip_serializing_if = "Select::is_empty")]
     pub(crate) extra_deps: Select<BTreeSet<Label>>,
 
@@ -161,6 +166,7 @@ impl Default for CommonAttributes {
             data: Default::default(),
             data_glob: Default::default(),
             deps: Default::default(),
+            build_script_dep: Default::default(),
             extra_deps: Default::default(),
             deps_dev: Default::default(),
             edition: Default::default(),
@@ -495,19 +501,17 @@ impl CrateContext {
         });
 
         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,
-                    },
+            // Kept out of `common_attrs.deps` (which feeds workspace-member alias
+            // generation) so the crate is not aliased to itself.
+            common_attrs.build_script_dep = Some(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_deps = annotation.deps.build_deps.clone().map(new_crate_dep);
             let build_link_deps = annotation.deps.build_link_deps.clone().map(new_crate_dep);

crate_universe/src/rendering.rs

@@ -680,13 +680,14 @@ impl Renderer {
         krate: &CrateContext,
         target: &TargetAttributes,
     ) -> Result<RustProcMacro> {
+        let mut deps = krate.common_attrs.deps.clone();
+        if let Some(dep) = krate.common_attrs.build_script_dep.clone() {
+            deps.insert(dep, None);
+        }
         Ok(RustProcMacro {
             name: target.crate_name.clone(),
             deps: SelectSet::new(
-                self.make_deps(
-                    krate.common_attrs.deps.clone(),
-                    krate.common_attrs.extra_deps.clone(),
-                ),
+                self.make_deps(deps, krate.common_attrs.extra_deps.clone()),
                 platforms,
             ),
             proc_macro_deps: SelectSet::new(
@@ -707,13 +708,14 @@ impl Renderer {
         krate: &CrateContext,
         target: &TargetAttributes,
     ) -> Result<RustLibrary> {
+        let mut deps = krate.common_attrs.deps.clone();
+        if let Some(dep) = krate.common_attrs.build_script_dep.clone() {
+            deps.insert(dep, None);
+        }
         Ok(RustLibrary {
             name: target.crate_name.clone(),
             deps: SelectSet::new(
-                self.make_deps(
-                    krate.common_attrs.deps.clone(),
-                    krate.common_attrs.extra_deps.clone(),
-                ),
+                self.make_deps(deps, krate.common_attrs.extra_deps.clone()),
                 platforms,
             ),
             proc_macro_deps: SelectSet::new(
@@ -742,10 +744,11 @@ 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 crate_deps = krate.common_attrs.deps.clone();
+        if let Some(dep) = krate.common_attrs.build_script_dep.clone() {
+            crate_deps.insert(dep, None);
+        }
+        let mut deps = self.make_deps(crate_deps, krate.common_attrs.extra_deps.clone());
         let mut proc_macro_deps = self.make_deps(
             krate.common_attrs.proc_macro_deps.clone(),
             krate.common_attrs.extra_proc_macro_deps.clone(),