[clangd] Strip the ' [some-check-name]' suffix from clang-tidy diagnostics. The check name is reported in Diagnostic.code.

[kadircet]

LGTM, we might need to make sure clients that do not show "code" field become aware of this before LLVM9 releases

clangd/Diagnostics.cpp

if (const char *ClangDiag = getDiagnosticCode(Diag.ID)) {
       Diag.Source = Diag::Clang;
       continue;
     }
     if (Tidy != nullptr) {
       std::string TidyDiag = Tidy->getCheckName(Diag.ID);
       if (!TidyDiag.empty()) {
         Diag.Name = std::move(TidyDiag);
         Diag.Source = Diag::ClangTidy;
+        // clang-tidy bakes the name into diagnostic messages. Strip it out.
+        // It would be much nicer to make clang-tidy not do this.
+        auto CleanMessage = [&](std::string &Msg) {
+          StringRef Rest(Msg);
+          if (Rest.consume_back("]") && Rest.consume_back(Diag.Name) &&
+              Rest.consume_back(" ["))
+            Msg.resize(Rest.size());
+        };
+        CleanMessage(Diag.Message);
+        for (auto& Note : Diag.Notes)
+          CleanMessage(Note.Message);
         continue;
       }
     }
   }
   return std::move(Output);
 }
 
 void StoreDiags::BeginSourceFile(const LangOptions &Opts,

test/clangd/diagnostics.test

 # CHECK-NEXT:            "line": 0
 # CHECK-NEXT:          }
 # CHECK-NEXT:        },
 # CHECK-NEXT:        "severity": 2,
 # CHECK-NEXT:        "source": "clang"
 # CHECK-NEXT:      },
 # CHECK-NEXT:      {
 # CHECK-NEXT:        "code": "bugprone-sizeof-expression",
-# CHECK-NEXT:        "message": "Suspicious usage of 'sizeof(K)'; did you mean 'K'? [bugprone-sizeof-expression]",
+# CHECK-NEXT:        "message": "Suspicious usage of 'sizeof(K)'; did you mean 'K'?",
 # CHECK-NEXT:        "range": {
 # CHECK-NEXT:          "end": {
 # CHECK-NEXT:            "character": 12,
 # CHECK-NEXT:            "line": 1
 # CHECK-NEXT:          },
 # CHECK-NEXT:          "start": {
 # CHECK-NEXT:            "character": 6,
 # CHECK-NEXT:            "line": 1

unittests/clangd/DiagnosticsTests.cpp

TEST(DiagnosticsTest, ClangTidy) {
   TU.ClangTidyChecks =
       "-*, bugprone-sizeof-expression, bugprone-macro-repeated-side-effects, "
       "modernize-deprecated-headers";
   EXPECT_THAT(
       TU.build().getDiagnostics(),
       UnorderedElementsAre(
           AllOf(Diag(Test.range("deprecated"),
                      "inclusion of deprecated C++ header 'assert.h'; consider "
-                     "using 'cassert' instead [modernize-deprecated-headers]"),
+                     "using 'cassert' instead"),
                 DiagSource(Diag::ClangTidy),
                 DiagName("modernize-deprecated-headers"),
                 WithFix(Fix(Test.range("deprecated"), "<cassert>",
                             "change '\"assert.h\"' to '<cassert>'"))),
           Diag(Test.range("doubled"),
-               "suspicious usage of 'sizeof(sizeof(...))' "
-               "[bugprone-sizeof-expression]"),
+               "suspicious usage of 'sizeof(sizeof(...))'"),
           AllOf(
               Diag(Test.range("macroarg"),
                    "side effects in the 1st macro argument 'X' are repeated in "
-                   "macro expansion [bugprone-macro-repeated-side-effects]"),
+                   "macro expansion"),
               DiagSource(Diag::ClangTidy),
               DiagName("bugprone-macro-repeated-side-effects"),
-              WithNote(Diag(Test.range("macrodef"),
-                            "macro 'SQUARE' defined here "
-                            "[bugprone-macro-repeated-side-effects]"))),
+              WithNote(
+                  Diag(Test.range("macrodef"), "macro 'SQUARE' defined here"))),
           Diag(Test.range("macroarg"),
                "multiple unsequenced modifications to 'y'")));
 }
 
 TEST(DiagnosticsTest, Preprocessor) {
   // This looks like a preamble, but there's an #else in the middle!
   // Check that:
   //  - the #else doesn't generate diagnostics (we had this bug)