clang-format: Slightly weaken AlignAfterOpenBracket=AlwaysBreak.

If a call takes a single argument, using AlwaysBreak can lead to lots
of wasted lines and additional indentation without improving the
readability in a significant way.

Before:
  caaaaaaaaaaaall(
      caaaaaaaaaaaall(
          caaaaaaaaaaaall(
              caaaaaaaaaaaaaaaaaaaaaaall(aaaaaaaaaaaaaa, aaaaaaaaa))));

After:
  caaaaaaaaaaaall(caaaaaaaaaaaall(caaaaaaaaaaaall(
      caaaaaaaaaaaaaaaaaaaaaaall(aaaaaaaaaaaaaa, aaaaaaaaa))));

llvm-svn: 263709

2 files changed, 35 insertions, 6 deletions

diff --git a/clang/lib/Format/ContinuationIndenter.cpp b/clang/lib/Format/ContinuationIndenter.cpp
index 4e5a29426a2..9cff34bc3df 100644
--- a/clang/lib/Format/ContinuationIndenter.cpp
+++ b/clang/lib/Format/ContinuationIndenter.cpp
@@ -356,7 +356,17 @@ void ContinuationIndenter::addTokenOnCurrentLine(LineState &State, bool DryRun,
       Previous.isOneOf(tok::l_paren, TT_TemplateOpener, tok::l_square) &&
       State.Column > getNewLineColumn(State) &&
       (!Previous.Previous ||
-       !Previous.Previous->isOneOf(tok::kw_for, tok::kw_while, tok::kw_switch)))
+       !Previous.Previous->isOneOf(tok::kw_for, tok::kw_while,
+                                   tok::kw_switch)) &&
+      // Don't do this for simple (no expressions) one-argument function calls
+      // as that feels like needlessly wasting whitespace, e.g.:
+      //
+      //   caaaaaaaaaaaall(
+      //       caaaaaaaaaaaall(
+      //           caaaaaaaaaaaall(
+      //               caaaaaaaaaaaaaaaaaaaaaaall(aaaaaaaaaaaaaa, aaaaaaaaa))));
+      Current.FakeLParens.size() > 0 &&
+      Current.FakeLParens.back() > prec::Unknown)
     State.Stack.back().NoLineBreak = true;
 
   if (Style.AlignAfterOpenBracket != FormatStyle::BAS_DontAlign &&
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 6e57dcc23f9..ff932c88c7c 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -4461,12 +4461,31 @@ TEST_F(FormatTest, AlignsAfterOpenBracket) {
                "    aaaaaaaaaaa aaaaaaaaa,\n"
                "    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa);",
                Style);
-  verifyFormat("SomeLongVariableName->someFunction(\n"
-               "    foooooooo(\n"
-               "        aaaaaaaaaaaaaaa,\n"
-               "        aaaaaaaaaaaaaaaaaaaaa,\n"
-               "        aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa));",
+  verifyFormat("SomeLongVariableName->someFunction(foooooooo(\n"
+               "    aaaaaaaaaaaaaaa,\n"
+               "    aaaaaaaaaaaaaaaaaaaaa,\n"
+               "    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa));",
                Style);
+  verifyFormat(
+      "aaaaaaaaaaaaaaaaaaaaaaaa(aaaaaaaaaaaaaaaaaaaaa(\n"
+      "    aaaaaaaaaaaaaaaaaaaa(aaaaaaaaaaaaaaaaa, aaaaaaaaaaaaaaaa)));",
+      Style);
+  verifyFormat(
+      "aaaaaaaaaaaaaaaaaaaaaaaa(aaaaaaaaaa.aaaaaaaaaa(\n"
+      "    aaaaaaaaaaaaaaaaaaaa(aaaaaaaaaaaaaaaaa, aaaaaaaaaaaaaaaa)));",
+      Style);
+  verifyFormat(
+      "aaaaaaaaaaaaaaaaaaaaaaaa(\n"
+      "    aaaaaaaaaaaaaaaaaaaaa(\n"
+      "        aaaaaaaaaaaaaaaaaaaa(aaaaaaaaaaaaaaaaa, aaaaaaaaaaaaaaaa)),\n"
+      "    aaaaaaaaaaaaaaaa);",
+      Style);
+  verifyFormat(
+      "aaaaaaaaaaaaaaaaaaaaaaaa(\n"
+      "    aaaaaaaaaaaaaaaaaaaaa(\n"
+      "        aaaaaaaaaaaaaaaaaaaa(aaaaaaaaaaaaaaaaa, aaaaaaaaaaaaaaaa)) &&\n"
+      "    aaaaaaaaaaaaaaaa);",
+      Style);
 }
 
 TEST_F(FormatTest, ParenthesesAndOperandAlignment) {