release/18.x: [clang-format] Fix a crash with AlignArrayOfStructures option (#86420)

[llvmbot]

Backport cceedc9

Requested by: @owenca

[llvmbot]

@HazardyKnusperkeks What do you think about merging this PR to the release branch?

[llvmbot]

@llvm/pr-subscribers-clang-format

Author: None (llvmbot)

Changes

Backport cceedc9

Requested by: @owenca

---

Full diff: https://github.com/llvm/llvm-project/pull/91049.diff

2 Files Affected:

• (modified) clang/lib/Format/WhitespaceManager.cpp (+1-1)
• (modified) clang/unittests/Format/FormatTest.cpp (+16-2)

diff --git a/clang/lib/Format/WhitespaceManager.cpp b/clang/lib/Format/WhitespaceManager.cpp
index df84f97a8e8ac1..7525e6ee650b62 100644
--- a/clang/lib/Format/WhitespaceManager.cpp
+++ b/clang/lib/Format/WhitespaceManager.cpp
@@ -1466,7 +1466,7 @@ WhitespaceManager::CellDescriptions WhitespaceManager::getCells(unsigned Start,
                                                                 : Cell);
         // Go to the next non-comment and ensure there is a break in front
         const auto *NextNonComment = C.Tok->getNextNonComment();
-        while (NextNonComment->is(tok::comma))
+        while (NextNonComment && NextNonComment->is(tok::comma))
           NextNonComment = NextNonComment->getNextNonComment();
         auto j = i;
         while (Changes[j].Tok != NextNonComment && j < End)
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 88877e53d014c6..b43c16a026de3a 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -20955,7 +20955,14 @@ TEST_F(FormatTest, CatchAlignArrayOfStructuresRightAlignment) {
                 "    [0] = {1, 1},\n"
                 "    [1] { 1, 1, },\n"
                 "    [2] { 1, 1, },\n"
-                "};");
+                "};",
+                Style);
+  verifyNoCrash("test arr[] = {\n"
+                "#define FOO(i) {i, i},\n"
+                "SOME_GENERATOR(FOO)\n"
+                "{2, 2}\n"
+                "};",
+                Style);
 
   verifyFormat("return GradForUnaryCwise(g, {\n"
                "                                {{\"sign\"}, \"Sign\",  "
@@ -21208,7 +21215,14 @@ TEST_F(FormatTest, CatchAlignArrayOfStructuresLeftAlignment) {
                 "    [0] = {1, 1},\n"
                 "    [1] { 1, 1, },\n"
                 "    [2] { 1, 1, },\n"
-                "};");
+                "};",
+                Style);
+  verifyNoCrash("test arr[] = {\n"
+                "#define FOO(i) {i, i},\n"
+                "SOME_GENERATOR(FOO)\n"
+                "{2, 2}\n"
+                "};",
+                Style);
 
   verifyFormat("return GradForUnaryCwise(g, {\n"
                "                                {{\"sign\"}, \"Sign\", {\"x\", "

[owenca]

@HazardyKnusperkeks can you approve it too?

[tstellar]

@owenca (or anyone else). If you would like to add a note about this fix in the release notes (completely optional). Please reply to this comment with a one or two sentence description of the fix. When you are done, please add the release:note label to this PR.