fix: sourcemaps not working in preloads in older Electron versions

Fixes #1099

Author: connor4312

CHANGELOG.md

@@ -8,6 +8,7 @@ This changelog records changes to stable releases since 1.50.2. "TBA" changes he
 - fix: remove redundant `__proto__` prop on recent V8 versions ([ref](https://github.com/microsoft/vscode/issues/130365))
 - fix: debug ports being auto forwarded after detach ([#1092](https://github.com/microsoft/vscode-js-debug/issues/1092))
 - fix: don't incorrectly scope sourcemap resolution to node_modules ([#1100](https://github.com/microsoft/vscode-js-debug/issues/1100))
+- fix: sourcemaps not working in preloads in older Electron versions ([#1099](https://github.com/microsoft/vscode-js-debug/issues/1099))
 - feat: add node_internals to skipFiles by default ([#1091](https://github.com/microsoft/vscode-js-debug/issues/1091))
 - feat: allow using a .ps1 script as a runtimeExectuable ([#1093](https://github.com/microsoft/vscode-js-debug/issues/1093))
 - feat: avoid attaching to scripts in .rc files ([ref](https://github.com/microsoft/vscode/issues/127717))

src/adapter/threads.ts

@@ -1102,6 +1102,11 @@ export class Thread implements IVariableStoreDelegate {
       return;
     }
 
+    // normalize paths paths that old Electron versions can add (#1099)
+    if (urlUtils.isAbsolute(event.url)) {
+      event.url = urlUtils.absolutePathToFileUrl(event.url);
+    }
+
     if (this._sourceContainer.scriptsById.has(event.scriptId)) {
       return;
     }