[clang-format] restore indent in conditionals when AlignOperands is DontAlign

[krasimir]

Summary

After D50078, we're experiencing unexpected un-indent using a style combining AlignOperands: DontAlign with BreakBeforeTernaryOperators: false, such as Google's JavaScript style:

% bin/clang-format -style=google ~/test.js
aaaaaaaaaaa = bbbbbbbb ? cccccccccccccccccc() :
dddddddddd             ? eeeeeeeeeeeeee :
                         fffff;

The issue lies with the interaction of AlignOperands: DontAlign and the edited code section in ContinuationIndenter.cpp, which de-dents the intent by Style.ContinuationIndentWidth. From the documentation of AlignOperands: DontAlign:

The wrapped lines are indented ContinuationIndentWidth spaces from the start of the line.

So the de-dent effectively erases the necessary ContinuationIndentWidth in that case.

This patch restores the AlignOperands: DontAlign behavior, producing:

% bin/clang-format -style=google ~/test.js
aaaaaaaaaaa = bbbbbbbb ? cccccccccccccccccc() :
    dddddddddd         ? eeeeeeeeeeeeee :
                         fffff;

[sammccall]

This may not be the right long-term solution, but the current behavior is pretty broken and this is cheap.

clang/unittests/Format/FormatTest.cpp

6287

aligning the question marks here is a bit weird (given DontAlign) but that's another patch.

If we disable the question-column behavior with dontalign, this patch will be completely dead, right?
May want to add a FIXME to remove in that case.

[krasimir]

• add a FIXME

[krasimir]

• refresh Phabricator diff

[krasimir]

• try to update Phabricator diff

[Typz]

clang/unittests/Format/FormatTest.cpp

6287

I don't think this is so weird: even with DontAlign, there are other cases when some alignment is performed: for exemple when formatting tables in column.

As I see it, ternary operator formatting is a similar case of 2D formatting, and while it needs indeed to respect the "general" line wrapping/indent mode (as per AlignOperands), it is OK to keep the alignment of the ternary operator themselves : otherwise, the whole "mode" for ternary operators need to be disabled and makes no sense.

But anyway this is a different patch as you mentioned, and maybe some user of DontAlign can come up with a better approach for formatting ternary ops in that case.

[krasimir]

clang/unittests/Format/FormatTest.cpp

6287

Added a FIXME. I think disabling question-column alignment with dontalign indeed can make this patch obsolete.

6287

Agree, this is more of a policy / preference on how we want these snippets to look like with DontAlign. We should discuss it in more detail whenever we attempt to refine this later. In a way, this touches back on djasper's comment on D50078, which I believe was left unaddressed:

I don't think the alignment of "?" and ":" (in the WhitespaceManager) should be always on. I think we'd need a flag for that part

clang/lib/Format/ContinuationIndenter.cpp

if (((NextNonComment->is(tok::colon) && NextNonComment->Next &&
           NextNonComment->Next->FakeLParens.back() == prec::Conditional) ||
          (Previous.is(tok::colon) && !Current.FakeLParens.empty() &&
           Current.FakeLParens.back() == prec::Conditional)) &&
         !State.Stack.back().IsWrappedConditional) {
       // NOTE: we may tweak this slightly:
       //    * not remove the 'lead' ContinuationIndentWidth
       //    * always un-indent by the operator when
       //    BreakBeforeTernaryOperators=true
-      unsigned Indent =
-          State.Stack.back().Indent - Style.ContinuationIndentWidth;
+      unsigned Indent = State.Stack.back().Indent;
+      if (Style.AlignOperands != FormatStyle::OAS_DontAlign) {
+        Indent -= Style.ContinuationIndentWidth;
+      }
       if (Style.BreakBeforeTernaryOperators &&
           State.Stack.back().UnindentOperator)
         Indent -= 2;
       return Indent;
     }
     return State.Stack.back().QuestionColumn;
   }
   if (Previous.is(tok::comma) && State.Stack.back().VariablePos != 0)

clang/unittests/Format/FormatTest.cpp

verifyFormat("return aaaaaaaaaaaaaaaaaaaaa\n"
                Style);
   verifyFormat("return aaaaaaaaaaaaaaaaaaaaaaaaa\n"
                "           ? aaaaaaaaaaaaaaaaaa ? bbbbbbbbbbbbbbbbbb\n"
                "             : cccccccccccccccc ? dddddddddddddddddd\n"
                "                                : eeeeeeeeeeeeeeeeee\n"
                "       : bbbbbbbbbbbbbbbbbbbbbbb ? 2222222222222222\n"
                "                                 : 3333333333333333;",
                Style);
+
+  Style.AlignOperands = FormatStyle::OAS_DontAlign;
+  Style.BreakBeforeTernaryOperators = false;
+  // FIXME: Aligning the question marks is weird given DontAlign.
+  // Consider disabling this alignment in this case. Also check whether this
+  // will render the adjustment from https://reviews.llvm.org/D82199
+  // unnecessary.
+  verifyFormat("int x = aaaaaaaaaaaaaaa ? aaaaaaaaaaaaaaaaaa :\n"
+               "    bbbb                ? cccccccccccccccccc :\n"
+               "                          ddddd;\n",
+               Style);
 }
 
 TEST_F(FormatTest, BreaksConditionalExpressionsAfterOperator) {
   FormatStyle Style = getLLVMStyle();
   Style.BreakBeforeTernaryOperators = false;
   Style.ColumnLimit = 70;
   verifyFormat(
       "aaaa(aaaaaaaaaaaaaaaaaaaa, aaaaaaaaaaaaaaaaaaaaaaaaaa ?\n"