non-synthesized symbols can inherit docs too

Author: QuietMisdreavus

lib/SymbolGraphGen/Edge.cpp

@@ -58,10 +58,16 @@ void Edge::serialize(llvm::json::OStream &OS) const {
       }
     }
 
+    const ValueDecl *InheritingDecl = nullptr;
+    if (const auto *ID = Source.getDeclInheritingDocs()) {
+      if (Target.getSymbolDecl() == ID || Source.getSynthesizedBaseTypeDecl())
+        InheritingDecl = ID;
+    }
+    
     // If our source symbol is a synthesized decl, write in information about
     // where it's inheriting docs from.
-    if (Source.getSynthesizedBaseTypeDecl()) {
-      Symbol inheritedSym(Graph, Source.getSymbolDecl(), nullptr);
+    if (InheritingDecl) {
+      Symbol inheritedSym(Graph, InheritingDecl, nullptr);
       SmallString<256> USR, Display;
       llvm::raw_svector_ostream DisplayOS(Display);
 

lib/SymbolGraphGen/Symbol.cpp

@@ -171,15 +171,32 @@ void Symbol::serializeRange(size_t InitialIndentation,
   });
 }
 
-void Symbol::serializeDocComment(llvm::json::OStream &OS) const {
-  if (Graph->Walker.Options.SkipInheritedDocs && SynthesizedBaseTypeDecl) {
-    return;
-  }
+const ValueDecl *Symbol::getDeclInheritingDocs() const {
+  // get the decl that would provide docs for this symbol
   const auto *DocCommentProvidingDecl =
-      dyn_cast_or_null<ValueDecl>(
-          getDocCommentProvidingDecl(VD, /*AllowSerialized=*/true));
-  if (!DocCommentProvidingDecl) {
-    DocCommentProvidingDecl = VD;
+    dyn_cast_or_null<ValueDecl>(
+      getDocCommentProvidingDecl(VD, /*AllowSerialized=*/true));
+  
+  // if the decl is the same as the one for this symbol, we're not
+  // inheriting docs, so return null.
+  if (DocCommentProvidingDecl == VD) {
+    return nullptr;
+  } else {
+    // otherwise, return whatever `getDocCommentProvidingDecl` returned.
+    // it will be null if there are no decls that provide docs for this
+    // symbol.
+    return DocCommentProvidingDecl;
+  }
+}
+
+void Symbol::serializeDocComment(llvm::json::OStream &OS) const {
+  const auto *DocCommentProvidingDecl = VD;
+  if (!Graph->Walker.Options.SkipInheritedDocs) {
+    DocCommentProvidingDecl = dyn_cast_or_null<ValueDecl>(
+      getDocCommentProvidingDecl(VD, /*AllowSerialized=*/true));
+    if (!DocCommentProvidingDecl) {
+      DocCommentProvidingDecl = VD;
+    }
   }
   auto RC = DocCommentProvidingDecl->getRawComment(/*SerializedOK=*/true);
   if (RC.isEmpty()) {

lib/SymbolGraphGen/Symbol.h

@@ -111,6 +111,11 @@ class Symbol {
   void printPath(llvm::raw_ostream &OS) const;
 
   void getUSR(SmallVectorImpl<char> &USR) const;
+  
+  /// If this symbol is inheriting docs from a parent class, protocol, or default
+  /// implementation, returns that decl. Returns null if there are no docs or if
+  /// the symbol has its own doc comments to render.
+  const ValueDecl *getDeclInheritingDocs() const;
 
   static bool supportsKind(DeclKind Kind);
 };

test/SymbolGraph/Relationships/Synthesized/InheritedDocs.swift

@@ -3,23 +3,30 @@
 
 // RUN: %target-swift-symbolgraph-extract -module-name InheritedDocs -I %t -pretty-print -output-dir %t
 // RUN: %FileCheck %s --input-file %t/InheritedDocs.symbols.json --check-prefixes CHECK,DOCS
+// RUN: %FileCheck %s --input-file %t/InheritedDocs.symbols.json --check-prefixes IMPL
 
 // RUN: %target-swift-symbolgraph-extract -module-name InheritedDocs -I %t -pretty-print -output-dir %t -skip-inherited-docs
 // RUN: %FileCheck %s --input-file %t/InheritedDocs.symbols.json --check-prefixes CHECK,SKIP
+// RUN: %FileCheck %s --input-file %t/InheritedDocs.symbols.json --check-prefixes IMPL
 
 // RUN: %empty-directory(%t)
 // RUN: %target-build-swift %s -module-name InheritedDocs -emit-module -emit-module-path %t/InheritedDocs.swiftmodule -emit-symbol-graph -emit-symbol-graph-dir %t/ -skip-inherited-docs
 // RUN: %FileCheck %s --input-file %t/InheritedDocs.symbols.json --check-prefixes SKIP
 
 // DOCS-COUNT-3: Some Function
-// SKIP-COUNT-2: Some Function
+// SKIP-COUNT-1: Some Function
 
 // CHECK:            "source": "s:13InheritedDocs1PPAAE8someFuncyyF::SYNTHESIZED::s:13InheritedDocs1SV"
 // CHECK-NEXT:       "target": "s:13InheritedDocs1SV"
-// CHECK-NEXT:       "sourceOrigin": {
-// CHECK-NEXT:         "identifier": "s:13InheritedDocs1PPAAE8someFuncyyF"
+// CHECK-NEXT:       "sourceOrigin"
+// CHECK-NEXT:         "identifier": "s:13InheritedDocs1PP8someFuncyyF"
 // CHECK-NEXT:         "displayName": "P.someFunc()"
-// CHECK-NEXT:       }
+
+// IMPL:             "source": "s:13InheritedDocs1PPAAE8someFuncyyF"
+// IMPL-NEXT:        "target": "s:13InheritedDocs1PP8someFuncyyF"
+// IMPL-NEXT:        "sourceOrigin"
+// IMPL-NEXT:          "identifier": "s:13InheritedDocs1PP8someFuncyyF"
+// IMPL-NEXT:          "displayName": "P.someFunc()"
 
 /// Protocol P
 public protocol P {