Use pseudoparser-based folding ranges in ClangdServer.

[kadircet]

as discussed offline i don't see much value in having an extra flag to choose between ast-based and pseudo-based implementation, as the pseudo-based one is a super-set of the ast-based implementation. hence it shouldn't be regressing change in any way, therefore i am in favor of just using the pseudo based implementation inside clangdserver at all times (this is already hidden behind a flag ATM).

independent of that, branch cut is next tuesday. so i'd rather not land it until the cut happens (existing implementation is also crashing, but it's the devil we know and it would be nice to not introduce new failures).

clang-tools-extra/clangd/ClangdServer.cpp

855

i think choice of runQuick deserves a comment. something like We want to make sure folding ranges are always available for all the open files, hence prefer runQuick to not wait for operations on other files

[usaxena95]

Removed option to fallback to AST based implementation.

[usaxena95]

Let us land this after the branch cut then.

[hokein]

The change looks good to me.

as discussed offline i don't see much value in having an extra flag to choose between ast-based and pseudo-based implementation, as the pseudo-based one is a super-set of the ast-based implementation. hence it shouldn't be regressing change in any way, therefore i am in favor of just using the pseudo based implementation inside clangdserver at all times (this is already hidden behind a flag ATM).

+1

independent of that, branch cut is next tuesday. so i'd rather not land it until the cut happens (existing implementation is also crashing, but it's the devil we know and it would be nice to not introduce new failures).

What the main concern here? This feature is hidden under a flag which is off by default (and I don't think any user would turn it because the syntax-tree implementation is crashy), it should not affect any users, so it seems fine to land it even before the branch cut.

clang-tools-extra/clangd/ClangdServer.cpp

auto Action =
         CB(clangd::getDocumentSymbols(InpAST->AST));
       };
   WorkScheduler->runWithAST("DocumentSymbols", File, std::move(Action),
                             Transient);
 }
 
 void ClangdServer::foldingRanges(llvm::StringRef File,
                                  Callback<std::vector<FoldingRange>> CB) {
-  auto Action =
-      [CB = std::move(CB)](llvm::Expected<InputsAndAST> InpAST) mutable {
-        if (!InpAST)
-          return CB(InpAST.takeError());
-        CB(clangd::getFoldingRanges(InpAST->AST));
-      };
-  WorkScheduler->runWithAST("FoldingRanges", File, std::move(Action),
-                            Transient);
+  auto Code = getDraft(File);
+  if (!Code)
+    return CB(llvm::make_error<LSPError>(
+        "trying to compute folding ranges for non-added document",
+        ErrorCode::InvalidParams));
+  auto Action = [CB = std::move(CB), Code = std::move(*Code)]() mutable {
+    CB(clangd::getFoldingRanges(Code));
+  // We want to make sure folding ranges are always available for all the open
+  // files, hence prefer runQuick to not wait for operations on other files.
+  WorkScheduler->runQuick("FoldingRanges", File, std::move(Action));
 }
 
 void ClangdServer::findType(llvm::StringRef File, Position Pos,
                             Callback<std::vector<LocatedSymbol>> CB) {
   auto Action =
       [Pos, CB = std::move(CB)](llvm::Expected<InputsAndAST> InpAST) mutable {
         if (!InpAST)
           return CB(InpAST.takeError());
         CB(clangd::findType(InpAST->AST, Pos));
       };
   WorkScheduler->runWithAST("FindType", File, std::move(Action));
 }
 
 void ClangdServer::findImplementations(
     PathRef File, Position Pos, Callback<std::vector<LocatedSymbol>> CB) {
   auto Action = [Pos, CB = std::move(CB),