[clang] [clang-format] Handle raw string literals containing JSON code (PR #140666)

[Owen Pan via cfe-commits]

https://github.com/owenca created https://github.com/llvm/llvm-project/pull/140666

Fix #65400

>From 7c1c0d2ca413503d81cd71e6a005a608cdec479d Mon Sep 17 00:00:00 2001
From: Owen Pan <owenpiano at gmail.com>
Date: Mon, 19 May 2025 20:18:53 -0700
Subject: [PATCH] [clang-format] Handle raw string literals containing JSON
 code

Fix #65400
---
 clang/lib/Format/Format.cpp                   |  6 +++--
 clang/tools/clang-format/ClangFormat.cpp      |  4 ++--
 .../unittests/Format/FormatTestRawStrings.cpp | 22 +++++++++++++++++++
 3 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index b41a98ecb5be1..0cfa061681053 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -3808,8 +3808,10 @@ reformat(const FormatStyle &Style, StringRef Code,
     tooling::Replacements Replaces =
         Formatter(*Env, Style, Status).process().first;
     // add a replacement to remove the "x = " from the result.
-    Replaces = Replaces.merge(
-        tooling::Replacements(tooling::Replacement(FileName, 0, 4, "")));
+    if (Code.starts_with("x = ")) {
+      Replaces = Replaces.merge(
+          tooling::Replacements(tooling::Replacement(FileName, 0, 4, "")));
+    }
     // apply the reformatting changes and the removal of "x = ".
     if (applyAllReplacements(Code, Replaces))
       return {Replaces, 0};
diff --git a/clang/tools/clang-format/ClangFormat.cpp b/clang/tools/clang-format/ClangFormat.cpp
index 08fe95fbe9f03..e40e04eac5472 100644
--- a/clang/tools/clang-format/ClangFormat.cpp
+++ b/clang/tools/clang-format/ClangFormat.cpp
@@ -491,8 +491,8 @@ static bool format(StringRef FileName, bool ErrorOnIncompleteFormat = false) {
   // To format JSON insert a variable to trick the code into thinking its
   // JavaScript.
   if (IsJson && !FormatStyle->DisableFormat) {
-    auto Err = Replaces.add(tooling::Replacement(
-        tooling::Replacement(AssumedFileName, 0, 0, "x = ")));
+    auto Err =
+        Replaces.add(tooling::Replacement(AssumedFileName, 0, 0, "x = "));
     if (Err)
       llvm::errs() << "Bad Json variable insertion\n";
   }
diff --git a/clang/unittests/Format/FormatTestRawStrings.cpp b/clang/unittests/Format/FormatTestRawStrings.cpp
index 0615fb1fad4c5..7a7aa88665554 100644
--- a/clang/unittests/Format/FormatTestRawStrings.cpp
+++ b/clang/unittests/Format/FormatTestRawStrings.cpp
@@ -988,6 +988,28 @@ fffffffffffffffffffff("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
                       )pb");)test",
                    Style));
 }
+
+TEST_F(FormatTestRawStrings, Json) {
+  auto Style = getLLVMStyle();
+  Style.RawStringFormats = {
+      {
+          /*Language=*/FormatStyle::LK_Json,
+          /*Delimiters=*/{"json"},
+          /*EnclosingFunctions=*/{},
+          /*CanonicalDelimiter=*/"",
+          /*BasedOnStyle=*/"llvm",
+      },
+  };
+
+  EXPECT_EQ(R"test(json = R"json({
+                "str": "test"
+              })json";)test",
+            format(R"test(json = R"json({
+  "str": "test"
+})json";)test",
+                   Style));
+}
+
 } // end namespace
 } // end namespace format
 } // end namespace clang