From 73573eaa39e4f09b35b35b29826b1fdc4a39f5f1 Mon Sep 17 00:00:00 2001
From: Evan Wallace <evan.exe@gmail.com>
Date: Fri, 16 Oct 2020 10:21:21 -0700
Subject: [PATCH] fix #463: use forward slashes in source maps

---
 CHANGELOG.md                 | 6 ++++++
 internal/bundler/linker.go   | 6 ++++--
 scripts/uglify-tests.js      | 2 +-
 scripts/verify-source-map.js | 4 +---
 4 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index a9ebf8c6315..39a6c754bfb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog
 
+## Unreleased
+
+* Fix backward slashes in source maps on Windows ([#463](https://github.com/evanw/esbuild/issues/463))
+
+    The relative path fix in the previous release caused a regression where paths in source maps contained `\` instead of `/` on Windows. That is incorrect because source map paths are URLs, not file system paths. This release replaces `\` with `/` for consistency on Windows.
+
 ## 0.7.15
 
 * Lower `export * as` syntax for ES2019 and below
diff --git a/internal/bundler/linker.go b/internal/bundler/linker.go
index 0342fd901a9..9f544bc84f3 100644
--- a/internal/bundler/linker.go
+++ b/internal/bundler/linker.go
@@ -3028,7 +3028,8 @@ func (c *linkerContext) generateCodeForFileInChunkJS(
 				for i, oldRelPath := range sourceMapClone.Sources {
 					absPath := c.fs.Join(sourceAbsDir, oldRelPath)
 					if relPath, ok := c.fs.Rel(chunkAbsDir, absPath); ok {
-						sourceMapClone.Sources[i] = relPath
+						// Make sure to always use forward slashes, even on Windows
+						sourceMapClone.Sources[i] = strings.ReplaceAll(relPath, "\\", "/")
 					}
 				}
 			}
@@ -3038,7 +3039,8 @@ func (c *linkerContext) generateCodeForFileInChunkJS(
 		// containing the output file
 		if sourceClone.KeyPath.Namespace == "file" {
 			if relPath, ok := c.fs.Rel(chunkAbsDir, sourceClone.KeyPath.Text); ok {
-				sourceClone.PrettyPath = relPath
+				// Make sure to always use forward slashes, even on Windows
+				sourceClone.PrettyPath = strings.ReplaceAll(relPath, "\\", "/")
 			}
 		}
 	}
diff --git a/scripts/uglify-tests.js b/scripts/uglify-tests.js
index d9284df40ae..442aa0e619f 100644
--- a/scripts/uglify-tests.js
+++ b/scripts/uglify-tests.js
@@ -156,7 +156,7 @@ async function test_case(service, test) {
     ].join("\n"), {
       input: input_formatted,
       output: output,
-      error: ex,
+      error: ex && ex.stack || ex,
     });
   }
 
diff --git a/scripts/verify-source-map.js b/scripts/verify-source-map.js
index cd78f595bb5..c54404bf4e6 100644
--- a/scripts/verify-source-map.js
+++ b/scripts/verify-source-map.js
@@ -256,9 +256,7 @@ async function check(kind, testCase, toSearch, { flags, entryPoints, crlf }) {
         const { source, line, column } = map.originalPositionFor({ line: outLine, column: outColumn })
 
         const inSource = isStdin ? '<stdin>' : files.find(x => path.basename(x).startsWith(id[0]))
-        const expectedSource = path.relative(__dirname, path.join(relativeTo, inSource).replace(/\\/g, '/'))
-        const observedSource = path.relative(__dirname, path.join(relativeTo, source).replace(/\\/g, '/'))
-        recordCheck(observedSource === expectedSource, `expected: ${expectedSource} observed: ${observedSource}`)
+        recordCheck(source === inSource, `expected: ${inSource} observed: ${source}`)
 
         const inJs = map.sourceContentFor(source)
         const inIndex = inJs.indexOf(`"${id}"`)