[clang-format] [JS] Don't break between template string and tag

Before:
    const x = veryLongIdentifier
        `hello`;
After:
    const x =
        veryLongIdentifier`hello`;

While it's allowed to have the template string and tag identifier
separated by a line break, currently the clang-format output is not
stable when a break is forced. Additionally, disallowing a line break
makes it clear that the identifier is actually a tag for a template
string.

Patch originally by mitchellwills (thanks!).

llvm-svn: 356447

1 files changed, 6 insertions, 0 deletions

diff --git a/clang/unittests/Format/FormatTestJS.cpp b/clang/unittests/Format/FormatTestJS.cpp
index ed8faabb3f2..528e4cf57cb 100644
--- a/clang/unittests/Format/FormatTestJS.cpp
+++ b/clang/unittests/Format/FormatTestJS.cpp
@@ -1962,6 +1962,12 @@ TEST_F(FormatTestJS, NestedTemplateStrings) {
 TEST_F(FormatTestJS, TaggedTemplateStrings) {
   verifyFormat("var x = html`<ul>`;");
   verifyFormat("yield `hello`;");
+  verifyFormat("var f = {\n"
+               "  param: longTagName`This is a ${\n"
+               "                    'really'} long line`\n"
+               "};",
+               "var f = {param: longTagName`This is a ${'really'} long line`};",
+               getGoogleJSStyleWithColumns(40));
 }
 
 TEST_F(FormatTestJS, CastSyntax) {