[clang] 08834ad - [clang-format] Fix a bug in merging short inline functions (#203754)

[via cfe-commits]

Author: owenca
Date: 2026-06-15T22:06:55-07:00
New Revision: 08834adcae88734e92359941c594c2ef6474c817

URL: https://github.com/llvm/llvm-project/commit/08834adcae88734e92359941c594c2ef6474c817
DIFF: https://github.com/llvm/llvm-project/commit/08834adcae88734e92359941c594c2ef6474c817.diff

LOG: [clang-format] Fix a bug in merging short inline functions (#203754)

Fixes #203209

Added: 
    

Modified: 
    clang/lib/Format/UnwrappedLineFormatter.cpp
    clang/unittests/Format/FormatTest.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/Format/UnwrappedLineFormatter.cpp b/clang/lib/Format/UnwrappedLineFormatter.cpp
index 42eabc065b1a8..7ea424349d923 100644
--- a/clang/lib/Format/UnwrappedLineFormatter.cpp
+++ b/clang/lib/Format/UnwrappedLineFormatter.cpp
@@ -314,8 +314,7 @@ class LineJoiner {
       }
     }
 
-    auto ShouldMergeShortFunctions = [this, &I, &NextLine, PreviousLine,
-                                      TheLine]() {
+    auto ShouldMergeShortFunctions = [&] {
       if (Style.AllowShortFunctionsOnASingleLine.isAll())
         return true;
 
@@ -326,12 +325,12 @@ class LineJoiner {
 
       if (Style.AllowShortFunctionsOnASingleLine.Inline &&
           !Style.AllowShortFunctionsOnASingleLine.Other) {
-        // Just checking TheLine->Level != 0 is not enough, because it
-        // provokes treating functions inside indented namespaces as short.
         if (Style.isJavaScript() && TheLine->Last->is(TT_FunctionLBrace))
           return true;
 
-        if (TheLine->Level != 0) {
+        // Just checking `TheLine->Level > 0` is not enough because it would
+        // cause functions inside indented namespaces to be treated as short.
+        if (const auto Level = TheLine->Level; Level > 0) {
           if (!PreviousLine)
             return false;
 
@@ -339,15 +338,16 @@ class LineJoiner {
           // Find the last line with lower level.
           const AnnotatedLine *Line = nullptr;
           for (auto J = I - 1; J >= AnnotatedLines.begin(); --J) {
-            assert(*J);
-            if (((*J)->InPPDirective && !(*J)->InMacroBody) ||
-                (*J)->isComment() || (*J)->Level > TheLine->Level) {
+            const auto *L = *J;
+            assert(L);
+            if (TheLine->InMacroBody && !L->InMacroBody)
+              break;
+            if (L->isComment() || (!TheLine->InPPDirective && L->InPPDirective))
               continue;
-            }
-            if ((*J)->Level < TheLine->Level ||
-                (Style.BreakBeforeBraces == FormatStyle::BS_Whitesmiths &&
-                 (*J)->First->is(tok::l_brace))) {
-              Line = *J;
+            if (L->Level < Level ||
+                (L->Level == Level && L->First->is(tok::l_brace) &&
+                 Style.BreakBeforeBraces == FormatStyle::BS_Whitesmiths)) {
+              Line = L;
               break;
             }
           }

diff  --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index a9e5d837843cd..acd584c811ae7 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -15425,6 +15425,15 @@ TEST_F(FormatTest, PullInlineOnlyFunctionDefinitionsIntoSingleLine) {
                "}",
                MergeInlineOnly);
 
+  MergeInlineOnly.NamespaceIndentation = FormatStyle::NI_All;
+  verifyFormat("namespace {\n"
+               "  class Class {\n"
+               "#define MACRO 1\n"
+               "    int f() { return 1; }\n"
+               "  };\n"
+               "} // namespace",
+               MergeInlineOnly);
+
   MergeInlineOnly.BreakBeforeBraces = FormatStyle::BS_Whitesmiths;
   verifyFormat("class Foo\n"
                "  {\n"