clang-format: ensure ternary operands are aligned

[zeule]

Set ParentState::AlignedTo for ternary operands.

[llvmorg-github-actions]

@llvm/pr-subscribers-clang-format

Author: Eugene Shalygin (zeule)

Changes

Set ParentState::AlignedTo for ternary operands.

---

Full diff: https://github.com/llvm/llvm-project/pull/196697.diff

2 Files Affected:

• (modified) clang/lib/Format/ContinuationIndenter.cpp (+15)
• (modified) clang/unittests/Format/AlignmentTest.cpp (+10)

diff --git a/clang/lib/Format/ContinuationIndenter.cpp b/clang/lib/Format/ContinuationIndenter.cpp
index b2f799bb33b01..7b3bf98670c1b 100644
--- a/clang/lib/Format/ContinuationIndenter.cpp
+++ b/clang/lib/Format/ContinuationIndenter.cpp
@@ -1276,6 +1276,21 @@ unsigned ContinuationIndenter::addTokenOnNewLine(LineState &State,
     CurrentState.BreakBeforeParameter = false;
     CurrentState.AlignedTo = &Current;
   }
+  if (!CurrentState.AlignedTo && Current.is(TT_ConditionalExpr)) {
+    switch (Style.AlignOperands) {
+    case FormatStyle::OAS_DontAlign:
+      break;
+    case FormatStyle::OAS_Align:
+        CurrentState.AlignedTo = Current.is(tok::question)
+                                     ? Current.getPrevious(tok::equal)
+                                     : Current.getPrevious(tok::question);
+      break;
+    case FormatStyle::OAS_AlignAfterOperator:
+      if (Current.is(tok::colon))
+        CurrentState.AlignedTo = Current.getPrevious(tok::question);
+      break;
+    }
+  }
 
   if (!DryRun) {
     unsigned MaxEmptyLinesToKeep = Style.MaxEmptyLinesToKeep + 1;
diff --git a/clang/unittests/Format/AlignmentTest.cpp b/clang/unittests/Format/AlignmentTest.cpp
index 971ceeefef582..9421a4c933b9e 100644
--- a/clang/unittests/Format/AlignmentTest.cpp
+++ b/clang/unittests/Format/AlignmentTest.cpp
@@ -3599,6 +3599,16 @@ TEST_F(AlignmentTest, ContinuedAligned) {
                "\t},\n"
                "\tvariant);",
                Style);
+
+  Style.ColumnLimit = 40;
+  Style.IndentWidth = Style.TabWidth = Style.ContinuationIndentWidth = 8;
+
+  verifyFormat("void f() {\n"
+               "\tint aaaaaaaaaaaaaaaaaaaa =\n"
+               "\t\t000000000000000001 ? 2\n"
+               "\t\t                   : 3;\n"
+               "}",
+               Style);
 }
 
 } // namespace

[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.

[HazardyKnusperkeks]

What happens if you ignore the previous value of AlignedTo?

[zeule]

I simply want to avoid repeatedly setting it. If it is set at this point, it was set by this very code fragment during the previous invocation of addTokensOnNewLine(). I think there is no harm to leave the old value, because the token stream isn't changing.

[HazardyKnusperkeks]

The assignment of AlignedTo is always unconditional in this function, I think we should keep it that way for consistency.

[zeule]

That certainly makes reading and reasoning simpler. Updated the code.

[zeule]

Thanks!