[PATCH] D93839: [clang-format] PR48594 BraceWrapping: SplitEmptyRecord ignored for templates

[MyDeveloperDay via Phabricator via cfe-commits]

MyDeveloperDay created this revision.
MyDeveloperDay added reviewers: curdeius, krasimir, klimek.
MyDeveloperDay added projects: clang, clang-format.
MyDeveloperDay requested review of this revision.

https://bugs.llvm.org/show_bug.cgi?id=48594

Empty or small templates were not being treated the same way as small classes especially when SplitEmptyRecord was set to true

This revision aims to help this by identifying a case when we should try not to merge the lines together

  BraceWrapping:
    AfterStruct: true
    SplitEmptyRecord: true
  BreakBeforeBraces: Custom

Input and expected formatted result:

  C++
  template <class> struct rep
  {
  };

Actual output:

  C++
  template <class> struct rep
  {};


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D93839

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


Index: clang/unittests/Format/FormatTest.cpp
===================================================================
--- clang/unittests/Format/FormatTest.cpp
+++ clang/unittests/Format/FormatTest.cpp
@@ -9891,6 +9891,55 @@
                "{\n"
                "} Foo_t;",
                Style);
+
+  Style.BraceWrapping.SplitEmptyRecord = true;
+  Style.BraceWrapping.AfterStruct = true;
+  verifyFormat("class rep\n"
+               "{\n"
+               "};",
+               Style);
+  verifyFormat("struct rep\n"
+               "{\n"
+               "};",
+               Style);
+  verifyFormat("template <typename T> class rep\n"
+               "{\n"
+               "};",
+               Style);
+  verifyFormat("template <typename T> struct rep\n"
+               "{\n"
+               "};",
+               Style);
+  verifyFormat("class rep\n"
+               "{\n"
+               "  int x;\n"
+               "};",
+               Style);
+  verifyFormat("struct rep\n"
+               "{\n"
+               "  int x;\n"
+               "};",
+               Style);
+  verifyFormat("template <typename T> class rep\n"
+               "{\n"
+               "  int x;\n"
+               "};",
+               Style);
+  verifyFormat("template <typename T> struct rep\n"
+               "{\n"
+               "  int x;\n"
+               "};",
+               Style);
+  verifyFormat("template <typename T> class rep // Foo\n"
+               "{\n"
+               "  int x;\n"
+               "};",
+               Style);
+  verifyFormat("template <typename T> struct rep // Bar\n"
+               "{\n"
+               "  int x;\n"
+               "};",
+               Style);
 }
 
 TEST_F(FormatTest, SplitEmptyStruct) {
Index: clang/lib/Format/UnwrappedLineFormatter.cpp
===================================================================
--- clang/lib/Format/UnwrappedLineFormatter.cpp
+++ clang/lib/Format/UnwrappedLineFormatter.cpp
@@ -248,6 +248,11 @@
         return !Style.BraceWrapping.SplitEmptyRecord && EmptyBlock
                    ? tryMergeSimpleBlock(I, E, Limit)
                    : 0;
+
+      if (Tok && Tok->is(tok::kw_template) &&
+          Style.BraceWrapping.SplitEmptyRecord && EmptyBlock) {
+        return 0;
+      }
     }
 
     // FIXME: TheLine->Level != 0 might or might not be the right check to do.
@@ -355,6 +360,21 @@
     if (TheLine->First->is(tok::l_brace) && I != AnnotatedLines.begin() &&
         I[-1]->First->isOneOf(tok::kw_case, tok::kw_default))
       return 0;
+
+    if (TheLine->Last->is(tok::l_brace) && I != AnnotatedLines.begin() &&
+        I[-1]->Last && Style.BraceWrapping.SplitEmptyRecord) {
+      const FormatToken *Previous = I[-1]->Last;
+      if (Previous && Previous->is(tok::comment)) {
+        Previous = Previous->getPreviousNonComment();
+      }
+      if (Previous) {
+        const FormatToken *PreviousPrevious = Previous->getPreviousNonComment();
+        if (PreviousPrevious && Previous->is(tok::identifier) &&
+            PreviousPrevious->isOneOf(tok::kw_class, tok::kw_struct))
+          return 0;
+      }
+    }
+
     // Try to merge a block with left brace wrapped that wasn't yet covered
     if (TheLine->Last->is(tok::l_brace)) {
       return !Style.BraceWrapping.AfterFunction ||


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