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[clang-format] Don't align comments over scopes
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We now stop aligning trailing comments on all closing braces, for
classes etc. we even check for the semicolon between the comment and the
brace.
    
Fixes #67906.
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@HazardyKnusperkeks
HazardyKnusperkeks committed Oct 25, 2023
1 parent 6242c8c commit 5efa84c
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Showing 4 changed files with 218 additions and 21 deletions.
4 changes: 4 additions & 0 deletions clang/docs/ClangFormatStyleOptions.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -980,6 +980,10 @@ the configuration (without a prefix: ``Auto``).
**AlignTrailingComments** (``TrailingCommentsAlignmentStyle``) :versionbadge:`clang-format 3.7` :ref:`<AlignTrailingComments>`
Control of trailing comments.

The alignment stops at closing braces after a line break, and only
followed by other closing braces, a (``do-``) ``while``, a lambda call, or
a semicolon.


.. note::

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4 changes: 4 additions & 0 deletions clang/include/clang/Format/Format.h
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Original file line number Diff line number Diff line change
Expand Up @@ -539,6 +539,10 @@ struct FormatStyle {

/// Control of trailing comments.
///
/// The alignment stops at closing braces after a line break, and only
/// followed by other closing braces, a (``do-``) ``while``, a lambda call, or
/// a semicolon.
///
/// \note
/// As of clang-format 16 this option is not a bool but can be set
/// to the options. Conventional bool options still can be parsed as before.
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53 changes: 44 additions & 9 deletions clang/lib/Format/WhitespaceManager.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1048,6 +1048,9 @@ void WhitespaceManager::alignChainedConditionals() {
}

void WhitespaceManager::alignTrailingComments() {
if (Style.AlignTrailingComments.Kind == FormatStyle::TCAS_Never)
return;

const int Size = Changes.size();
int MinColumn = 0;
int StartOfSequence = 0;
Expand Down Expand Up @@ -1118,16 +1121,48 @@ void WhitespaceManager::alignTrailingComments() {
}
}

// We don't want to align namespace end comments.
const bool DontAlignThisComment =
I > 0 && C.NewlinesBefore == 0 &&
Changes[I - 1].Tok->is(TT_NamespaceRBrace);
if (Style.AlignTrailingComments.Kind == FormatStyle::TCAS_Never ||
DontAlignThisComment) {
// We don't want to align comments which end a scope, which are here
// identified by most closing braces.
auto DontAlignThisComment = [](const auto *Tok) {
if (Tok->is(tok::semi)) {
Tok = Tok->getPreviousNonComment();
if (!Tok)
return false;
}
if (Tok->is(tok::r_paren)) {
// Back up past the parentheses and a `TT_DoWhile` that may precede.
Tok = Tok->MatchingParen;
if (!Tok)
return false;
Tok = Tok->getPreviousNonComment();
if (!Tok)
return false;
if (Tok->is(TT_DoWhile)) {
const auto *Prev = Tok->getPreviousNonComment();
if (!Prev) {
// A do-while-loop without braces.
return true;
}
Tok = Prev;
}
}

if (Tok->isNot(tok::r_brace))
return false;

while (Tok->Previous && Tok->Previous->is(tok::r_brace))
Tok = Tok->Previous;
return Tok->NewlinesBefore > 0;
};

if (I > 0 && C.NewlinesBefore == 0 &&
DontAlignThisComment(Changes[I - 1].Tok)) {
alignTrailingComments(StartOfSequence, I, MinColumn);
MinColumn = ChangeMinColumn;
MaxColumn = ChangeMinColumn;
StartOfSequence = I;
// Reset to initial values, but skip this change for the next alignment
// pass.
MinColumn = 0;
MaxColumn = INT_MAX;
StartOfSequence = I + 1;
} else if (BreakBeforeNext || Newlines > NewLineThreshold ||
(ChangeMinColumn > MaxColumn || ChangeMaxColumn < MinColumn) ||
// Break the comment sequence if the previous line did not end
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178 changes: 166 additions & 12 deletions clang/unittests/Format/FormatTestComments.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -182,7 +182,7 @@ TEST_F(FormatTestComments, UnderstandsSingleLineComments) {
"int a; // This is unrelated"));
EXPECT_EQ("class C {\n"
" void f() { // This does something ..\n"
" } // awesome..\n"
" } // awesome..\n"
"\n"
" int a; // This is unrelated\n"
"};",
Expand Down Expand Up @@ -3102,7 +3102,8 @@ TEST_F(FormatTestComments, DontAlignNamespaceComments) {
StringRef Input = "namespace A {\n"
" TESTSUITE(B) {\n"
" namespace C {\n"
" namespace D {} // namespace D\n"
" namespace D { //\n"
" } // namespace D\n"
" std::string Foo = Bar; // Comment\n"
" std::string BazString = Baz; // C2\n"
" } // namespace C\n"
Expand All @@ -3114,7 +3115,8 @@ TEST_F(FormatTestComments, DontAlignNamespaceComments) {
verifyFormat("namespace A {\n"
" TESTSUITE(B) {\n"
" namespace C {\n"
" namespace D {} // namespace D\n"
" namespace D { //\n"
" } // namespace D\n"
" std::string Foo = Bar; // Comment\n"
" std::string BazString = Baz; // C2\n"
" } // namespace C\n"
Expand All @@ -3126,7 +3128,8 @@ TEST_F(FormatTestComments, DontAlignNamespaceComments) {
verifyFormat("namespace A {\n"
" TESTSUITE(B) {\n"
" namespace C {\n"
" namespace D {} // namespace D\n"
" namespace D { //\n"
" } // namespace D\n"
" std::string Foo = Bar; // Comment\n"
" std::string BazString = Baz; // C2\n"
" } // namespace C\n"
Expand All @@ -3138,7 +3141,8 @@ TEST_F(FormatTestComments, DontAlignNamespaceComments) {
verifyFormat("namespace A {\n"
" TESTSUITE(B) {\n"
" namespace C {\n"
" namespace D {} // namespace D\n"
" namespace D { //\n"
" } // namespace D\n"
" std::string Foo = Bar; // Comment\n"
" std::string BazString = Baz; // C2\n"
" } // namespace C\n"
Expand All @@ -3151,7 +3155,8 @@ TEST_F(FormatTestComments, DontAlignNamespaceComments) {
verifyFormat("namespace A {\n"
" TESTSUITE(B) {\n"
" namespace C {\n"
" namespace D {} // namespace D\n"
" namespace D { //\n"
" } // namespace D\n"
" std::string Foo = Bar; // Comment\n"
" std::string BazString = Baz; // C2\n"
" } // namespace C\n"
Expand All @@ -3163,7 +3168,8 @@ TEST_F(FormatTestComments, DontAlignNamespaceComments) {
verifyFormat("namespace A {\n"
" TESTSUITE(B) {\n"
" namespace C {\n"
" namespace D {} // namespace D\n"
" namespace D { //\n"
" } // namespace D\n"
" std::string Foo = Bar; // Comment\n"
" std::string BazString = Baz; // C2\n"
" } // namespace C\n"
Expand All @@ -3175,7 +3181,8 @@ TEST_F(FormatTestComments, DontAlignNamespaceComments) {
verifyFormat("namespace A {\n"
" TESTSUITE(B) {\n"
" namespace C {\n"
" namespace D {} // namespace D\n"
" namespace D { //\n"
" } // namespace D\n"
" std::string Foo = Bar; // Comment\n"
" std::string BazString = Baz; // C2\n"
" } // namespace C\n"
Expand All @@ -3191,20 +3198,167 @@ TEST_F(FormatTestComments, DontAlignNamespaceComments) {
"}\n"
"// Comment";

#if 0
// FIXME: The following comment is aligned with the namespace comment.
verifyFormat("namespace A {\n"
" int Foo;\n"
" int Bar;\n"
"} // namespace A\n"
" // Comment",
"// Comment",
Input, Style);
#endif

Style.FixNamespaceComments = false;
verifyFormat(Input, Style);
}

TEST_F(FormatTestComments, DontAlignOverScope) {
verifyFormat("if (foo) {\n"
" int aLongVariable; // with comment\n"
" int f; // aligned\n"
"} // not aligned\n"
"int bar; // new align\n"
"int foobar; // group");

verifyFormat("if (foo) {\n"
" // something\n"
"} else {\n"
" int aLongVariable; // with comment\n"
" int f; // aligned\n"
"} // not aligned\n"
"int bar; // new align\n"
"int foobar; // group");

verifyFormat("if (foo) {\n"
" // something\n"
"} else if (foo) {\n"
" int aLongVariable; // with comment\n"
" int f; // aligned\n"
"} // not aligned\n"
"int bar; // new align\n"
"int foobar; // group");

verifyFormat("while (foo) {\n"
" int aLongVariable; // with comment\n"
" int f; // aligned\n"
"} // not aligned\n"
"int bar; // new align\n"
"int foobar; // group");

verifyFormat("for (;;) {\n"
" int aLongVariable; // with comment\n"
" int f; // aligned\n"
"} // not aligned\n"
"int bar; // new align\n"
"int foobar; // group");

verifyFormat("do {\n"
" int aLongVariable; // with comment\n"
" int f; // aligned\n"
"} while (foo); // not aligned\n"
"int bar; // new align\n"
"int foobar; // group");

verifyFormat("do\n"
" int aLongVariable; // with comment\n"
"while (foo); // not aigned\n"
"int bar; // new align\n"
"int foobar; // group");

verifyFormat("do\n"
" int aLongVariable; // with comment\n"
"/**/ while (foo); // not aigned\n"
"int bar; // new align\n"
"int foobar; // group");

verifyFormat("switch (foo) {\n"
"case 7: {\n"
" int aLongVariable; // with comment\n"
" int f; // aligned\n"
"} // case not aligned\n"
"} // switch also not aligned\n"
"int bar; // new align\n"
"int foobar; // group");

verifyFormat("switch (foo) {\n"
"default: {\n"
" int aLongVariable; // with comment\n"
" int f; // aligned\n"
"} // case not aligned\n"
"} // switch also not aligned\n"
"int bar; // new align\n"
"int foobar; // group");

verifyFormat("class C {\n"
" int aLongVariable; // with comment\n"
" int f; // aligned\n"
"}; // not aligned\n"
"int bar; // new align\n"
"int foobar; // group");

verifyFormat("struct S {\n"
" int aLongVariable; // with comment\n"
" int f; // aligned\n"
"}; // not aligned\n"
"int bar; // new align\n"
"int foobar; // group");

verifyFormat("union U {\n"
" int aLongVariable; // with comment\n"
" int f; // aligned\n"
"}; // not aligned\n"
"int bar; // new align\n"
"int foobar; // group");

verifyFormat("enum E {\n"
" aLongVariable, // with comment\n"
" f // aligned\n"
"}; // not aligned\n"
"int bar; // new align\n"
"int foobar; // group");

verifyFormat("void foo() {\n"
" {\n"
" int aLongVariable; // with comment\n"
" int f; // aligned\n"
" } // not aligned\n"
" int bar; // new align\n"
" int foobar; // group\n"
"}");

verifyFormat("auto longLambda = [] { // comment\n"
" int aLongVariable; // with comment\n"
" int f; // aligned\n"
"}; // not aligned\n"
"int bar; // new align\n"
"int foobar; // group\n"
"auto shortLambda = [] { return 5; }; // aligned");

verifyFormat("auto longLambdaResult = [] { // comment\n"
" int aLongVariable; // with comment\n"
" int f; // aligned\n"
"}(); // not aligned\n"
"int bar; // new align\n"
"int foobar; // group\n"
"auto shortLambda = [] { return 5; }(); // aligned");

verifyFormat(
"auto longLambdaResult = [](auto I, auto J) { // comment\n"
" int aLongVariable; // with comment\n"
" int f; // aligned\n"
"}(\"Input\", 5); // not aligned\n"
"int bar; // new align\n"
"int foobar; // group\n"
"auto shortL = [](auto I, auto J) { return 5; }(\"In\", 5); // aligned");

verifyFormat("enum E1 { V1, V2 }; // Aligned\n"
"enum E2 { LongerNames, InThis, Enum }; // Comments");

verifyFormat("class C {\n"
" int aLongVariable; // with comment\n"
" int f; // aligned\n"
"} /* middle comment */; // not aligned\n"
"int bar; // new align\n"
"int foobar; // group");
}

TEST_F(FormatTestComments, AlignsBlockCommentDecorations) {
EXPECT_EQ("/*\n"
" */",
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