[clang-tools-extra] [clangd] Allow specifying what headers are always included via "" or <> (PR #67749)

[Nathan Ridge via cfe-commits]

HighCommander4 wrote:

Anyways, I rebased the old version of the patch locally so that I could generate an interdiff, which I'll attach for reference:

<details>

```diff
diff --git a/clang-tools-extra/clangd/Config.h b/clang-tools-extra/clangd/Config.h
index 12ed1420c93e..3559591fce00 100644
--- a/clang-tools-extra/clangd/Config.h
+++ b/clang-tools-extra/clangd/Config.h
@@ -124,7 +124,7 @@ struct Config {
     // ::). All nested namespaces are affected as well.
     std::vector<std::string> FullyQualifiedNamespaces;
 
-    // List of regexes for inserting certain headers with <> or "".
+    // List of matcher functions for inserting certain headers with <> or "".
     std::vector<std::function<bool(llvm::StringRef)>> QuotedHeaders;
     std::vector<std::function<bool(llvm::StringRef)>> AngledHeaders;
   } Style;
diff --git a/clang-tools-extra/clangd/ConfigFragment.h b/clang-tools-extra/clangd/ConfigFragment.h
index 81474bbd86a5..f0d1080f6c83 100644
--- a/clang-tools-extra/clangd/ConfigFragment.h
+++ b/clang-tools-extra/clangd/ConfigFragment.h
@@ -302,12 +302,16 @@ struct Fragment {
     /// AngledHeaders (i.e. a header matches a regex in both QuotedHeaders and
     /// AngledHeaders), system headers use <> and non-system headers use "".
     /// These can match any suffix of the header file in question.
+    /// Matching is performed against the header text, not its absolute path
+    /// within the project.
     std::vector<Located<std::string>> QuotedHeaders;
     /// List of regexes for headers that should always be included with a
     /// <>-style include. By default, and in case of a conflict with
     /// AngledHeaders (i.e. a header matches a regex in both QuotedHeaders and
     /// AngledHeaders), system headers use <> and non-system headers use "".
     /// These can match any suffix of the header file in question.
+    /// Matching is performed against the header text, not its absolute path
+    /// within the project.
     std::vector<Located<std::string>> AngledHeaders;
   };
   StyleBlock Style;
diff --git a/clang-tools-extra/clangd/Headers.h b/clang-tools-extra/clangd/Headers.h
index e1f3eaa3397b..b91179da253e 100644
--- a/clang-tools-extra/clangd/Headers.h
+++ b/clang-tools-extra/clangd/Headers.h
@@ -9,7 +9,6 @@
 #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_HEADERS_H
 #define LLVM_CLANG_TOOLS_EXTRA_CLANGD_HEADERS_H
 
-#include "Config.h"
 #include "Protocol.h"
 #include "SourceCode.h"
 #include "index/Symbol.h"
diff --git a/clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp b/clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp
index 6d387fec9b38..bf264a5a44ee 100644
--- a/clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp
+++ b/clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp
@@ -11,6 +11,7 @@
 #include "ClangdServer.h"
 #include "CodeComplete.h"
 #include "Compiler.h"
+#include "Config.h"
 #include "Feature.h"
 #include "Matchers.h"
 #include "Protocol.h"
@@ -916,6 +917,41 @@ TEST(CompletionTest, NoIncludeInsertionWhenDeclFoundInFile) {
                           AllOf(named("Y"), Not(insertInclude()))));
 }
 
+TEST(CompletionTest, IncludeInsertionRespectsQuotedAngledConfig) {
+  TestTU TU;
+  TU.ExtraArgs.push_back("-I" + testPath("sub"));
+  TU.AdditionalFiles["sub/bar.h"] = "";
+  auto BarURI = URI::create(testPath("sub/bar.h")).toString();
+
+  Symbol Sym = cls("ns::X");
+  Sym.CanonicalDeclaration.FileURI = BarURI.c_str();
+  Sym.IncludeHeaders.emplace_back(BarURI, 1, Symbol::Include);
+  Annotations Test("int main() { ns::^ }");
+  TU.Code = Test.code().str();
+  auto Results = completions(TU, Test.point(), {Sym});
+  // Default for a local path is quoted include
+  EXPECT_THAT(Results.Completions,
+              ElementsAre(AllOf(named("X"), insertInclude("\"bar.h\""))));
+  {
+    Config C;
+    C.Style.AngledHeaders.push_back(
+        [](auto header) { return header == "bar.h"; });
+    WithContextValue WithCfg(Config::Key, std::move(C));
+    Results = completions(TU, Test.point(), {Sym});
+    EXPECT_THAT(Results.Completions,
+                ElementsAre(AllOf(named("X"), insertInclude("<bar.h>"))));
+  }
+  {
+    Config C;
+    C.Style.QuotedHeaders.push_back(
+        [](auto header) { return header == "bar.h"; });
+    WithContextValue WithCfg(Config::Key, std::move(C));
+    Results = completions(TU, Test.point(), {Sym});
+    EXPECT_THAT(Results.Completions,
+                ElementsAre(AllOf(named("X"), insertInclude("\"bar.h\""))));
+  }
+}
+
 TEST(CompletionTest, IndexSuppressesPreambleCompletions) {
   Annotations Test(R"cpp(
       #include "bar.h"
@@ -1134,8 +1170,8 @@ TEST(CodeCompleteTest, NoColonColonAtTheEnd) {
 }
 
 TEST(CompletionTests, EmptySnippetDoesNotCrash) {
-    // See https://github.com/clangd/clangd/issues/1216
-    auto Results = completions(R"cpp(
+  // See https://github.com/clangd/clangd/issues/1216
+  auto Results = completions(R"cpp(
         int main() {
           auto w = [&](auto &&f) { return f(f); };
           auto f = w([&](auto &&f) {
@@ -1151,18 +1187,18 @@ TEST(CompletionTests, EmptySnippetDoesNotCrash) {
 }
 
 TEST(CompletionTest, Issue1427Crash) {
-    // Need to provide main file signals to ensure that the branch in
-    // SymbolRelevanceSignals::computeASTSignals() that tries to
-    // compute a symbol ID is taken.
-    ASTSignals MainFileSignals;
-    CodeCompleteOptions Opts;
-    Opts.MainFileSignals = &MainFileSignals;
-    completions(R"cpp(
+  // Need to provide main file signals to ensure that the branch in
+  // SymbolRelevanceSignals::computeASTSignals() that tries to
+  // compute a symbol ID is taken.
+  ASTSignals MainFileSignals;
+  CodeCompleteOptions Opts;
+  Opts.MainFileSignals = &MainFileSignals;
+  completions(R"cpp(
       auto f = []() {
         1.0_^
       };
     )cpp",
-                {}, Opts);
+              {}, Opts);
 }
 
 TEST(CompletionTest, BacktrackCrashes) {
diff --git a/clang-tools-extra/clangd/unittests/ConfigCompileTests.cpp b/clang-tools-extra/clangd/unittests/ConfigCompileTests.cpp
index 0eea7ff01b48..efee23003067 100644
--- a/clang-tools-extra/clangd/unittests/ConfigCompileTests.cpp
+++ b/clang-tools-extra/clangd/unittests/ConfigCompileTests.cpp
@@ -555,7 +555,9 @@ TEST_F(ConfigCompileTests, Style) {
       return false;
     };
     EXPECT_TRUE(HeaderFilter("foo.h"));
+    EXPECT_TRUE(HeaderFilter("prefix/foo.h"));
     EXPECT_FALSE(HeaderFilter("bar.h"));
+    EXPECT_FALSE(HeaderFilter("foo.h/bar.h"));
   }
 
   {
```

</details>

https://github.com/llvm/llvm-project/pull/67749