[clang-format] Discourage breaks in submessage entries, hard rule

Summary:
Currently clang-format allows this for text protos:
```
submessage:
    { key: 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa' }
```
when it is under the column limit and when putting it all on one line exceeds the column limit.

This is not a very intuitive formatting, so I'd prefer having
```
submessage: {
  key: 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'
}
```
instead, even if it takes one line more.

This patch prevents clang-format from inserting a break between `: {` and similar cases.

Reviewers: djasper, sammccall

Reviewed By: sammccall

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D48063

llvm-svn: 334517

1 files changed, 32 insertions, 2 deletions

diff --git a/clang/unittests/Format/FormatTestTextProto.cpp b/clang/unittests/Format/FormatTestTextProto.cpp
index d62975feb44..8ef4bf9a40a 100644
--- a/clang/unittests/Format/FormatTestTextProto.cpp
+++ b/clang/unittests/Format/FormatTestTextProto.cpp
@@ -485,8 +485,15 @@ TEST_F(FormatTestTextProto, FormatsRepeatedListInitializers) {
   verifyFormat("keys: []");
   verifyFormat("keys: [ 1 ]");
   verifyFormat("keys: [ 'ala', 'bala' ]");
-  verifyFormat("keys:\n"
-               "    [ 'ala', 'bala', 'porto', 'kala', 'too', 'long', 'ng' ]");
+  verifyFormat("keys: [\n"
+               "  'ala',\n"
+               "  'bala',\n"
+               "  'porto',\n"
+               "  'kala',\n"
+               "  'too',\n"
+               "  'long',\n"
+               "  'ng'\n"
+               "]");
   verifyFormat("key: item\n"
                "keys: [\n"
                "  'ala',\n"
@@ -670,5 +677,28 @@ TEST_F(FormatTestTextProto, BreaksEntriesOfSubmessagesContainingSubmessages) {
                "}");
 }
 
+TEST_F(FormatTestTextProto, PreventBreaksBetweenKeyAndSubmessages) {
+  verifyFormat("submessage: {\n"
+               "  key: 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'\n"
+               "}");
+  verifyFormat("submessage {\n"
+               "  key: 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'\n"
+               "}");
+  verifyFormat("submessage: <\n"
+               "  key: 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'\n"
+               ">");
+  verifyFormat("submessage <\n"
+               "  key: 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'\n"
+               ">");
+  verifyFormat("repeatedd: [\n"
+               "  'eyaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'\n"
+               "]");
+  // "{" is going over the column limit.
+  verifyFormat(
+      "submessageeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee: {\n"
+      "  key: 'aaaaa'\n"
+      "}");
+}
+
 } // end namespace tooling
 } // end namespace clang