[PATCH] D73026: clang-format: [JS] fix `??` opreator wrapping.

[Martin Probst via Phabricator via cfe-commits]

mprobst created this revision.
mprobst added a reviewer: krasimir.
Herald added a project: clang.

clang-format currently treats the nullish coalescing operator `??` like
the ternary operator. That causes multiple nullish terms to be each
indented relative to the last `??`, as they would in a ternary.

The `??` operator is often used in chains though, and as such more
similar to other binary operators, such as `||`. So to fix the indent,
set its token type to `||`, so it inherits the same treatment.

This opens up the question of operator precedence. However, `??` is
required to be parenthesized when mixed with `||` and `&&`, so this is
not a problem that can come up in syntactically legal code.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D73026

Files:
  clang/lib/Format/FormatTokenLexer.cpp
  clang/unittests/Format/FormatTestJS.cpp


Index: clang/unittests/Format/FormatTestJS.cpp
===================================================================
--- clang/unittests/Format/FormatTestJS.cpp
+++ clang/unittests/Format/FormatTestJS.cpp
@@ -2294,6 +2294,11 @@
 
 TEST_F(FormatTestJS, NullishCoalescingOperator) {
   verifyFormat("const val = something ?? 'some other default';\n");
+  verifyFormat(
+      "const val = something ?? otherDefault ??\n"
+      "    evenMore ?? evenMore;\n",
+      "const val = something ?? otherDefault ?? evenMore ?? evenMore;\n",
+      getGoogleJSStyleWithColumns(40));
 }
 
 TEST_F(FormatTestJS, Conditional) {
Index: clang/lib/Format/FormatTokenLexer.cpp
===================================================================
--- clang/lib/Format/FormatTokenLexer.cpp
+++ clang/lib/Format/FormatTokenLexer.cpp
@@ -120,8 +120,11 @@
       Tokens.back()->Tok.setKind(tok::starequal);
       return;
     }
-    if (tryMergeTokens(JSNullishOperator, TT_JsNullishCoalescingOperator))
+    if (tryMergeTokens(JSNullishOperator, TT_JsNullishCoalescingOperator)) {
+      // Treat like the "||" operator (as opposed to the ternary ?).
+      Tokens.back()->Tok.setKind(tok::pipepipe);
       return;
+    }
     if (tryMergeTokens(JSNullPropagatingOperator,
                        TT_JsNullPropagatingOperator)) {
       // Treat like a regular "." access.


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