fix: set breakpoints predictably when launching with files (#1749)

Fixes #1748

CHANGELOG.md

@@ -4,7 +4,7 @@ This changelog records changes to stable releases since 1.50.2. "TBA" changes he
 
 ## Nightly (only)
 
-Nothing (yet)
+- fix: set breakpoints predictably when launching with files ([#1748](https://github.com/microsoft/vscode-js-debug/issues/1748))
 
 ## v1.80 (June 2023)
 

src/targets/browser/browserPathResolver.ts

@@ -67,6 +67,10 @@ export class BrowserSourcePathResolver extends SourcePathResolverBase<IOptions>
       return { url: utils.absolutePathToFileUrl(absolutePath), needsWildcard: false };
     }
 
+    if (baseUrl && utils.isFileUrl(baseUrl)) {
+      return { url: utils.absolutePathToFileUrlWithDetection(absolutePath), needsWildcard: false };
+    }
+
     let urlPath = utils.platformPathToUrlPath(path.relative(bestMatch[1], absolutePath));
     const urlPrefix = bestMatch[0].replace(/\/$|^\//g, '');
     if (urlPrefix) {

src/test/breakpoints/breakpoints-sets-file-uri-breakpoints-predictably-1748.txt

@@ -0,0 +1,7 @@
+{
+    allThreadsStopped : false
+    description : Paused on breakpoint
+    reason : breakpoint
+    threadId : <number>
+}
+<anonymous> @ ${fixturesDir}/scripts/hello.js:1:1

src/test/breakpoints/breakpointsTest.ts

@@ -1390,4 +1390,24 @@ describe('breakpoints', () => {
     await waitForPause(p);
     p.assertLog();
   });
+
+  itIntegrates('sets file uri breakpoints predictably (#1748)', async ({ r }) => {
+    createFileTree(testFixturesDir, {
+      'pages/main.html': '<script src="../scripts/hello.js"></script>',
+      'scripts/hello.js': 'console.log(42)',
+    });
+
+    const mainFile = join(testFixturesDir, 'pages/main.html');
+    const p = await r.launchUrl(absolutePathToFileUrlWithDetection(mainFile), {
+      url: undefined,
+      file: mainFile,
+    });
+
+    const source: Dap.Source = { path: join(testFixturesDir, 'scripts/hello.js') };
+    await p.dap.setBreakpoints({ source, breakpoints: [{ line: 1 }] });
+    p.load();
+
+    await waitForPause(p);
+    p.assertLog();
+  });
 });