[clang] [extract-api] Don't crash for category in libclang APIs

[dang]

Summary

Remove failure conditions for categories in libclang and return empty
content instead.

[dang]

Formatting fixes

[bnbarham]

clang/lib/ExtractAPI/Serialization/SymbolGraphSerializer.cpp

540–549

It's not really clear to me what the intended behavior was meant to be here, ie. whether if any parent fails we skip writing all *or* if we should be writing all valid parents. I'll leave that to someone that knows more about the symbolgraph output.

But this fixes the obvious crash, so that part is fine with me.

[dang]

clang/lib/ExtractAPI/Serialization/SymbolGraphSerializer.cpp

540–549

I think it is a bit of a grey area, having parent contexts and related symbols allows downstream clients to perform link resolution on declaration fragment chunks e.t.c I figured it would be best to do a best effort and provide the known parents.

clang/lib/ExtractAPI/Serialization/SymbolGraphSerializer.cpp

 
 template <typename RecordTy>
 bool generatePathComponents(
     const RecordTy &Record, const APISet &API,
     function_ref<void(const PathComponent &)> ComponentTransformer) {
   SmallVector<PathComponent, 4> ReverseComponenents;
   ReverseComponenents.emplace_back(Record.USR, Record.Name, Record.getKind());
   const auto *CurrentParent = &Record.ParentInformation;
+  bool FailedToFindParent = false;
   while (CurrentParent && !CurrentParent->empty()) {
     PathComponent CurrentParentComponent(CurrentParent->ParentUSR,
                                          CurrentParent->ParentName,
                                          CurrentParent->ParentKind);
 
     auto *ParentRecord = CurrentParent->ParentRecord;
     // Slow path if we don't have a direct reference to the ParentRecord
     if (!ParentRecord)
       ParentRecord = API.findRecordForUSR(CurrentParent->ParentUSR);
 
     // If the parent is a category then we need to pretend this belongs to the
     // associated interface.
     if (auto *CategoryRecord =
             dyn_cast_or_null<ObjCCategoryRecord>(ParentRecord)) {
       ParentRecord = API.findRecordForUSR(CategoryRecord->Interface.USR);
       CurrentParentComponent = PathComponent(CategoryRecord->Interface.USR,
                                              CategoryRecord->Interface.Name,
                                              APIRecord::RK_ObjCInterface);
     }
 
     // The parent record doesn't exist which means the symbol shouldn't be
     // treated as part of the current product.
-    if (!ParentRecord)
-      return true;
+    if (!ParentRecord) {
+      FailedToFindParent = true;
+      break;
+    }
 
     ReverseComponenents.push_back(std::move(CurrentParentComponent));
     CurrentParent = &ParentRecord->ParentInformation;
   }
 
   for (const auto &PC : reverse(ReverseComponenents))
     ComponentTransformer(PC);
 
-  return false;
+  return FailedToFindParent;
 }
+
 Object serializeParentContext(const PathComponent &PC, Language Lang) {
   Object ParentContextElem;
   ParentContextElem["usr"] = PC.USR;
   ParentContextElem["name"] = PC.Name;
   ParentContextElem["kind"] = serializeSymbolKind(PC.Kind, Lang)["identifier"];
   return ParentContextElem;
 }
 
 template <typename RecordTy>
 Array generateParentContexts(const RecordTy &Record, const APISet &API,
                              Language Lang) {
   Array ParentContexts;
-  if (generatePathComponents(
-          Record, API, [Lang, &ParentContexts](const PathComponent &PC) {
-            ParentContexts.push_back(serializeParentContext(PC, Lang));
-          }))
-    ParentContexts.clear();
+  generatePathComponents(Record, API,
+                         [Lang, &ParentContexts](const PathComponent &PC) {
+                           ParentContexts.push_back(
+                               serializeParentContext(PC, Lang));
+                         });
+
+  // The last component would be the record itself so let's remove it.
+  if (!ParentContexts.empty())
     ParentContexts.pop_back();
 
   return ParentContexts;
 }
 
 } // namespace
 
 void SymbolGraphSerializer::anchor() {}
 
 /// Defines the format version emitted by SymbolGraphSerializer.

 
 std::optional<Object>
 SymbolGraphSerializer::serializeSingleSymbolSGF(StringRef USR,
                                                 const APISet &API) {
   APIRecord *Record = API.findRecordForUSR(USR);
   if (!Record)
     return {};
 
+  if (isa<ObjCCategoryRecord>(Record))
+    return {};
+
   Object Root;
   APIIgnoresList EmptyIgnores;
   SymbolGraphSerializer Serializer(API, EmptyIgnores,
                                    /*Options.Compact*/ {true},
                                    /*ShouldRecurse*/ false);
   Serializer.serializeSingleRecord(Record);
   serializeObject(Root, "symbolGraph", Serializer.serializeCurrentGraph());
 

clang/test/Index/extract-api-cursor.m

 @end
 
 /// Derived docs
 @interface Derived: Base
 /// Derived method docs
 - (void)derivedMethodWithValue:(id<Protocol>)value;
 @end
 
+/// This won't show up in docs because we can't serialize it
+@interface Derived ()
+/// Derived method in category docs, won't show up either.
+- (void)derivedMethodInCategory;
+@end
+
 // RUN: c-index-test -single-symbol-sgfs local %s | FileCheck %s
 
 // Checking for Foo
 // CHECK: "parentContexts":[]
 // CHECK-SAME: "relatedSymbols":[]
 // CHECK-SAME: "relationships":[]
 // CHECK-SAME: "text":"Foo docs"
 // CHECK-SAME: "kind":{"displayName":"Structure","identifier":"objective-c.struct"}

 // CHECK-SAME: "relatedSymbols":[]
 // CHECK-SAME: "relationships":[]
 // CHECK-SAME: "text":"Base docs"
 // CHECK-SAME: "kind":{"displayName":"Class","identifier":"objective-c.class"}
 // CHECK-SAME: "title":"Base"
 
 // Checking for baseProperty
 // CHECK-NEXT: "parentContexts":[{"kind":"objective-c.class","name":"Base","usr":"c:objc(cs)Base"}]
-// CHECK-SAME:"relatedSymbols":[{"accessLevel":"public","declarationLanguage":"objective-c"
+// CHECK-SAME: "relatedSymbols":[{"accessLevel":"public","declarationLanguage":"objective-c"
 // CHECK-SAME: "isSystem":false
 // CHECK-SAME: "usr":"c:@S@Foo"}]
 // CHECK-SAME: "relationships":[{"kind":"memberOf","source":"c:objc(cs)Base(py)baseProperty","target":"c:objc(cs)Base"
 // CHECK-SAME: "text":"Base property docs"
 // CHECK-SAME: "kind":{"displayName":"Instance Property","identifier":"objective-c.property"}
 // CHECK-SAME: "title":"baseProperty"
 
 // Checking for baseMethodWithArg
 // CHECK-NEXT: "parentContexts":[{"kind":"objective-c.class","name":"Base","usr":"c:objc(cs)Base"}]
-// CHECK-SAME:"relatedSymbols":[]
+// CHECK-SAME: "relatedSymbols":[]
 // CHECK-SAME: "relationships":[{"kind":"memberOf","source":"c:objc(cs)Base(im)baseMethodWithArg:","target":"c:objc(cs)Base"
 // CHECK-SAME: "text":"Base method docs"
 // CHECK-SAME: "kind":{"displayName":"Instance Method","identifier":"objective-c.method"}
 // CHECK-SAME: "title":"baseMethodWithArg:"
 
 // Checking for Protocol
 // CHECK-NEXT: "parentContexts":[]
 // CHECK-SAME: "relatedSymbols":[]
 // CHECK-SAME: "relationships":[]
 // CHECK-SAME: "text":"Protocol docs"
 // CHECK-SAME: "kind":{"displayName":"Protocol","identifier":"objective-c.protocol"}
 // CHECK-SAME: "title":"Protocol"
 
 // Checking for protocolProperty
 // CHECK-NEXT: "parentContexts":[{"kind":"objective-c.protocol","name":"Protocol","usr":"c:objc(pl)Protocol"}]
-// CHECK-SAME:"relatedSymbols":[{"accessLevel":"public","declarationLanguage":"objective-c"
+// CHECK-SAME: "relatedSymbols":[{"accessLevel":"public","declarationLanguage":"objective-c"
 // CHECK-SAME: "isSystem":false
 // CHECK-SAME: "usr":"c:@S@Foo"}]
 // CHECK-SAME: "relationships":[{"kind":"memberOf","source":"c:objc(pl)Protocol(py)protocolProperty","target":"c:objc(pl)Protocol"
 // CHECK-SAME: "text":"Protocol property docs"
 // CHECK-SAME: "kind":{"displayName":"Instance Property","identifier":"objective-c.property"}
 // CHECK-SAME: "title":"protocolProperty"
 
 // Checking for Derived
 // CHECK-NEXT: "parentContexts":[]
-// CHECK-SAME:"relatedSymbols":[{"accessLevel":"public","declarationLanguage":"objective-c"
+// CHECK-SAME: "relatedSymbols":[{"accessLevel":"public","declarationLanguage":"objective-c"
 // CHECK-SAME: "isSystem":false
 // CHECK-SAME: "usr":"c:objc(cs)Base"}]
 // CHECK-SAME: "relationships":[{"kind":"inheritsFrom","source":"c:objc(cs)Derived","target":"c:objc(cs)Base"
 // CHECK-SAME: "text":"Derived docs"
 // CHECK-SAME: "kind":{"displayName":"Class","identifier":"objective-c.class"}
 // CHECK-SAME: "title":"Derived"
 
 // Checking for derivedMethodWithValue
 // CHECK-NEXT: "parentContexts":[{"kind":"objective-c.class","name":"Derived","usr":"c:objc(cs)Derived"}]
-// CHECK-SAME:"relatedSymbols":[]
+// CHECK-SAME: "relatedSymbols":[]
 // CHECK-SAME: "relationships":[{"kind":"memberOf","source":"c:objc(cs)Derived(im)derivedMethodWithValue:","target":"c:objc(cs)Derived"
 // CHECK-SAME: "text":"Derived method docs"
 // CHECK-SAME: "kind":{"displayName":"Instance Method","identifier":"objective-c.method"}
 // CHECK-SAME: "title":"derivedMethodWithValue:"
+
+// CHECK-NOT: This won't show up in docs because we can't serialize it
+// CHECK-NOT: Derived method in category docs, won't show up either.