[clang] 4a7bf42 - [clang-format] Don't count template template parameter as declaration (#95025)

[via cfe-commits]

Author: Emilia Kond
Date: 2024-06-22T12:51:36+03:00
New Revision: 4a7bf42a9b83144db8a11ac06cce4da21166e6a2

URL: 
https://github.com/llvm/llvm-project/commit/4a7bf42a9b83144db8a11ac06cce4da21166e6a2
DIFF: 
https://github.com/llvm/llvm-project/commit/4a7bf42a9b83144db8a11ac06cce4da21166e6a2.diff

LOG: [clang-format] Don't count template template parameter as declaration 
(#95025)

In ContinuationIndenter::mustBreak, a break is required between a
template declaration and the function/class declaration it applies to,
if the template declaration spans multiple lines.

However, this also includes template template parameters, which can
cause extra erroneous line breaks in some declarations.

This patch makes template template parameters not be counted as template
declarations.

Fixes https://github.com/llvm/llvm-project/issues/93793
Fixes https://github.com/llvm/llvm-project/issues/48746

Added: 
    

Modified: 
    clang/lib/Format/TokenAnnotator.cpp
    clang/unittests/Format/TokenAnnotatorTest.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/Format/TokenAnnotator.cpp 
b/clang/lib/Format/TokenAnnotator.cpp
index 55c5ecee45e0c..89e134144d433 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -127,7 +127,7 @@ class AnnotatingParser {
                    SmallVector<ScopeType> &Scopes)
       : Style(Style), Line(Line), CurrentToken(Line.First), AutoFound(false),
         IsCpp(Style.isCpp()), LangOpts(getFormattingLangOpts(Style)),
-        Keywords(Keywords), Scopes(Scopes) {
+        Keywords(Keywords), Scopes(Scopes), TemplateDeclarationDepth(0) {
     assert(IsCpp == LangOpts.CXXOperatorNames);
     Contexts.push_back(Context(tok::unknown, 1, /*IsExpression=*/false));
     resetTokenMetadata();
@@ -1266,16 +1266,22 @@ class AnnotatingParser {
   }
 
   bool parseTemplateDeclaration() {
-    if (CurrentToken && CurrentToken->is(tok::less)) {
-      CurrentToken->setType(TT_TemplateOpener);
-      next();
-      if (!parseAngle())
-        return false;
-      if (CurrentToken)
-        CurrentToken->Previous->ClosesTemplateDeclaration = true;
-      return true;
-    }
-    return false;
+    if (!CurrentToken || CurrentToken->isNot(tok::less))
+      return false;
+
+    CurrentToken->setType(TT_TemplateOpener);
+    next();
+
+    TemplateDeclarationDepth++;
+    const bool WellFormed = parseAngle();
+    TemplateDeclarationDepth--;
+    if (!WellFormed)
+      return false;
+
+    if (CurrentToken && TemplateDeclarationDepth == 0)
+      CurrentToken->Previous->ClosesTemplateDeclaration = true;
+
+    return true;
   }
 
   bool consumeToken() {
@@ -3091,6 +3097,8 @@ class AnnotatingParser {
   // same decision irrespective of the decisions for tokens leading up to it.
   // Store this information to prevent this from causing exponential runtime.
   llvm::SmallPtrSet<FormatToken *, 16> NonTemplateLess;
+
+  int TemplateDeclarationDepth;
 };
 
 static const int PrecedenceUnaryOperator = prec::PointerToMember + 1;

diff  --git a/clang/unittests/Format/TokenAnnotatorTest.cpp 
b/clang/unittests/Format/TokenAnnotatorTest.cpp
index 12c4b7fdd5ac2..d3b310fe59527 100644
--- a/clang/unittests/Format/TokenAnnotatorTest.cpp
+++ b/clang/unittests/Format/TokenAnnotatorTest.cpp
@@ -584,6 +584,23 @@ TEST_F(TokenAnnotatorTest, 
UnderstandsNonTemplateAngleBrackets) {
   EXPECT_TOKEN(Tokens[20], tok::greater, TT_BinaryOperator);
 }
 
+TEST_F(TokenAnnotatorTest, UnderstandsTemplateTemplateParameters) {
+  auto Tokens = annotate("template <template <typename...> typename X,\n"
+                         "          template <typename...> class Y,\n"
+                         "          typename... T>\n"
+                         "class A {};");
+  ASSERT_EQ(Tokens.size(), 28u) << Tokens;
+  EXPECT_TOKEN(Tokens[1], tok::less, TT_TemplateOpener);
+  EXPECT_TOKEN(Tokens[3], tok::less, TT_TemplateOpener);
+  EXPECT_TOKEN(Tokens[6], tok::greater, TT_TemplateCloser);
+  EXPECT_FALSE(Tokens[6]->ClosesTemplateDeclaration);
+  EXPECT_TOKEN(Tokens[11], tok::less, TT_TemplateOpener);
+  EXPECT_TOKEN(Tokens[14], tok::greater, TT_TemplateCloser);
+  EXPECT_FALSE(Tokens[14]->ClosesTemplateDeclaration);
+  EXPECT_TOKEN(Tokens[21], tok::greater, TT_TemplateCloser);
+  EXPECT_TRUE(Tokens[21]->ClosesTemplateDeclaration);
+}
+
 TEST_F(TokenAnnotatorTest, UnderstandsWhitespaceSensitiveMacros) {
   FormatStyle Style = getLLVMStyle();
   Style.WhitespaceSensitiveMacros.push_back("FOO");


        
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