clang-format: [JS] fix template string width counting.

Summary:
Simply looking at the final text greatly simplifies the algorithm and also
fixes a reported issue. This requires duplicating the "actual encoding width"
logic, but that seems cleaner than the column acrobatics before.

Reviewers: djasper, bkramer

Subscribers: cfe-commits, klimek

Differential Revision: http://reviews.llvm.org/D20208

llvm-svn: 269747

1 files changed, 9 insertions, 0 deletions

diff --git a/clang/unittests/Format/FormatTestJS.cpp b/clang/unittests/Format/FormatTestJS.cpp
index 72d8948bb7a..485e8224c32 100644
--- a/clang/unittests/Format/FormatTestJS.cpp
+++ b/clang/unittests/Format/FormatTestJS.cpp
@@ -1076,6 +1076,8 @@ TEST_F(FormatTestJS, TemplateStrings) {
                getGoogleJSStyleWithColumns(34)); // Barely doesn't fit.
   verifyFormat("var x = `hello ${world}` >= some();",
                getGoogleJSStyleWithColumns(35)); // Barely fits.
+  verifyFormat("var x = `hellö ${wörld}` >= söme();",
+               getGoogleJSStyleWithColumns(35)); // Fits due to UTF-8.
   verifyFormat("var x = `hello\n"
             "  ${world}` >=\n"
             "    some();",
@@ -1097,6 +1099,13 @@ TEST_F(FormatTestJS, TemplateStrings) {
                getGoogleJSStyleWithColumns(13));
   verifyFormat("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(\n"
                "    `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`);");
+  // Repro for an obscure width-miscounting issue with template strings.
+  verifyFormat(
+      "someLongVariable =\n"
+      "    "
+      "`${logPrefix[11]}/${logPrefix[12]}/${logPrefix[13]}${logPrefix[14]}`;",
+      "someLongVariable = "
+      "`${logPrefix[11]}/${logPrefix[12]}/${logPrefix[13]}${logPrefix[14]}`;");
 
   // Make sure template strings get a proper ColumnWidth assigned, even if they
   // are first token in line.