[clang-format] Fix AlwaysBreakAfterDefinitionReturnType incompatibility with BreakBeforeBraces: Stroustrup

[curdeius]

Summary

I have found a bug when using a style like:

AlwaysBreakAfterDefinitionReturnType: true
BreakBeforeBraces: Stroustrup

I attach a straightforward patch that passes the tests.
However, I think that the issue may be actually somewhere deeper, e.g. in Line.Last pointing incorrectly to a different token than l_brace (cf. the patch).

[djasper]

I am happy to get this in as is especially as it is good to have the tests. I also agree that there is an underlying issue which we should look at in more detail. Can you add a FIXME to this effect?

lib/Format/TokenAnnotator.cpp

1293

Can you make this:

!Line.Last->isOneOf(tok::semi, tok::comment)

That seems to be the most obvious exception I can think of.

[curdeius]

• [clang-format] Fix {AlwaysBreakAfterDefinitionReturnType: true} not working with {BreakBeforeBraces: Stroustrup}.
• [clang-format] Add FIXME and check for a tok::semi or a tok::comment.

[curdeius]

• Format.

[djasper]

Do you have commit access or should I commit this for you?

[curdeius]

I don't have it. Please commit it.

[djasper]

Submitted as r215633.

lib/Format/TokenAnnotator.cpp

if (Current->Type == TT_LineComment) {
       Current->SpacesRequiredBefore = 1;
     }
 
     Current->MustBreakBefore =
         Current->MustBreakBefore || mustBreakBefore(Line, *Current);
 
     if (Style.AlwaysBreakAfterDefinitionReturnType &&
         InFunctionDecl && Current->Type == TT_FunctionDeclarationName &&
-        Line.Last->is(tok::l_brace))  // Only for definitions.
+        !Line.Last->isOneOf(tok::semi, tok::comment))  // Only for definitions.
+      // FIXME: Line.Last points to other characters than tok::semi
+      // and tok::lbrace.
       Current->MustBreakBefore = true;
 
     Current->CanBreakBefore =
         Current->MustBreakBefore || canBreakBefore(Line, *Current);
     unsigned ChildSize = 0;
     if (Current->Previous->Children.size() == 1) {
       FormatToken &LastOfChild = *Current->Previous->Children[0]->Last;
       ChildSize = LastOfChild.isTrailingComment() ? Style.ColumnLimit

unittests/Format/FormatTest.cpp

TEST_F(FormatTest, AlwaysBreakAfterDefinitionReturnType) {
   FormatStyle AfterType = getLLVMStyle();
   AfterType.AlwaysBreakAfterDefinitionReturnType = true;
   verifyFormat("const char *\n"
                "f(void) {\n"  // Break here.
                "  return \"\";\n"
                "}\n"
                "const char *bar(void);\n",  // No break here.
                AfterType);
+  verifyFormat("template <class T>\n"
+               "T *\n"
+               "f(T &c) {\n"  // Break here.
+               "  return NULL;\n"
+               "}\n"
+               "template <class T> T *f(T &c);\n",  // No break here.
+               AfterType);
+  AfterType.BreakBeforeBraces = FormatStyle::BS_Stroustrup;
+  verifyFormat("const char *\n"
+               "f(void)\n"  // Break here.
+               "{\n"
+               "  return \"\";\n"
+               "}\n"
+               "const char *bar(void);\n",  // No break here.
+               AfterType);
+  verifyFormat("template <class T>\n"
+               "T *\n"  // Problem here: no line break
+               "f(T &c)\n"  // Break here.
+               "{\n"
+               "  return NULL;\n"
+               "}\n"
+               "template <class T> T *f(T &c);\n",  // No break here.
+               AfterType);
 }
 
 TEST_F(FormatTest, AlwaysBreakBeforeMultilineStrings) {
   FormatStyle NoBreak = getLLVMStyle();
   NoBreak.AlwaysBreakBeforeMultilineStrings = false;
   FormatStyle Break = getLLVMStyle();
   Break.AlwaysBreakBeforeMultilineStrings = true;
   verifyFormat("aaaa = \"bbbb\"\n"