WorkspaceFolder Uri.fsPath drive letter normalization to lowercase on Windows causing extension issues

[enlyth]

I'll give an example where this behaviour creates issues, which I think is fairly common, e.g. spawning Jest by running a command like npm test via process.spawn, like the vscode-jest extension does, while using a transformer like babel-jest.

The extension gets its path via vscode.workspace, and WorkspaceFolder.Uri.fsPath is normalized to a lower-case drive letter.

The following code demonstrates this issue:

const childProcess = require("child_process");

// Uppercase drive letter, tests will run fine
const cwd = "C:\\src2\\myproj";

// Lowercase drive letter, this will FAIL, unable to resolve modules when running
// const cwd = "c:\\src2\\myproj"; 

const proc = childProcess.spawn(
  "npm",
  [
    "test",
    "--",
    "--json",
    "--useStderr",
    "--outputFile",
    "C:\\Users\\BORIS~1.POP\\AppData\\Local\\Temp/jest_runner.json",
    "--watch",
  ],
  { cwd: cwd, shell: true, env: process.env }
);

fsPath returning an uppercase drive letter on Windows seems to have been already suggested here:
#42159 (comment)

• VSCode Version: 1.32.0-insider
• OS Version: Windows 10 Build 17134

Steps to Reproduce:

1. Set up any project which uses babel-jest, and Jest
2. Run code above from command line

Does this issue occur when all extensions are disabled?: Irrelevant

[jrieken]

This is the designed and something we cannot change anymore. It's is explicitly spelled out in the docs.

If your downlevel code depends on the casing of the windows drive letter (which IMO is questionable) you should enforce the case yourself.

[vscodebot]

The described behavior is how it is expected to work. If you disagree, please explain what is expected and what is not in more detail. See also our issue reporting guidelines.

Happy Coding!