From 2787a2793ad791c81891768a837fc10c2abed40f Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Thu, 11 Oct 2018 09:31:04 -0700
Subject: [PATCH] Skip writing json file if it is going to overwrite same
 location Fixes #24715

---
 src/compiler/emitter.ts                       |  4 +++-
 .../requireOfJsonFileWithoutOutDir.errors.txt | 20 -------------------
 2 files changed, 3 insertions(+), 21 deletions(-)
 delete mode 100644 tests/baselines/reference/requireOfJsonFileWithoutOutDir.errors.txt

diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index 6b4b3a5c5104e..8617c8fccdeeb 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -52,7 +52,9 @@ namespace ts {
         else {
             const ownOutputFilePath = getOwnEmitOutputFilePath(sourceFile.fileName, host, getOutputExtension(sourceFile, options));
             // If json file emits to the same location skip writing it, if emitDeclarationOnly skip writing it
-            const jsFilePath = options.emitDeclarationOnly ? undefined : ownOutputFilePath;
+            const isJsonEmittedToSameLocation = isJsonSourceFile(sourceFile) &&
+                comparePaths(sourceFile.fileName, ownOutputFilePath, host.getCurrentDirectory(), !host.useCaseSensitiveFileNames()) === Comparison.EqualTo;
+            const jsFilePath = options.emitDeclarationOnly || isJsonEmittedToSameLocation ? undefined : ownOutputFilePath;
             const sourceMapFilePath = !jsFilePath || isJsonSourceFile(sourceFile) ? undefined : getSourceMapFilePath(jsFilePath, options);
             // For legacy reasons (ie, we have baselines capturing the behavior), js files don't report a .d.ts output path - this would only matter if `declaration` and `allowJs` were both on, which is currently an error
             const isJs = isSourceFileJS(sourceFile);
diff --git a/tests/baselines/reference/requireOfJsonFileWithoutOutDir.errors.txt b/tests/baselines/reference/requireOfJsonFileWithoutOutDir.errors.txt
deleted file mode 100644
index 07f0f1b84d76c..0000000000000
--- a/tests/baselines/reference/requireOfJsonFileWithoutOutDir.errors.txt
+++ /dev/null
@@ -1,20 +0,0 @@
-error TS5055: Cannot write file 'tests/cases/compiler/b.json' because it would overwrite input file.
-  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig.
-
-
-!!! error TS5055: Cannot write file 'tests/cases/compiler/b.json' because it would overwrite input file.
-!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig.
-==== tests/cases/compiler/file1.ts (0 errors) ====
-    import b1 = require('./b.json');
-    let x = b1.a;
-    import b2 = require('./b.json');
-    if (x) {
-        let b = b2.b;
-        x = (b1.b === b);
-    }
-    
-==== tests/cases/compiler/b.json (0 errors) ====
-    {
-        "a": true,
-        "b": "hello"
-    }
\ No newline at end of file