docs: create debugging.md

Author: MichaelCurrin

docs/development/advanced/debugging.md

@@ -0,0 +1,37 @@
+# Debugging
+> How to deal with errors in the extension
+
+## Test shell commands
+
+This snippet of code can be used to for testing that a basic command works without error and output can be shown.
+
+```typescript
+/**
+ * Debug tool for checking that a basic command works.
+ * Replace the `makeAndFillCommitMsg` call with `test` to use this.
+ */
+async function _test(repository: Repository) {
+  vscode.window.showInformationMessage("Testing")
+
+  let cwd = repository.rootUri.path;
+
+  vscode.window.showInformationMessage(cwd)
+
+  const resp = await _execute(cwd, 'git --version')
+  vscode.window.showInformationMessage(`${resp.stdout} -- ${resp.stderr}`)
+}
+```
+
+### Background
+
+This was prompted by issue [#93](https://github.com/MichaelCurrin/auto-commit-msg/issues/93) on Windows.
+
+The output in the debug mode did not work because the shell command failed to spawn at all using `exec()` in Node. 
+
+I printed the `cwd` value in the VS Code info box using code above. I realized that when it was used with `git` in `cmd` on Windows that the path was not valid. Showing as `/c:/...` with a leading forward-slash appropriate for Linux/macOS but not Windows `cmd`.
+
+This is the temporary hack until the `vscode` library has a fix:
+
+```typescript
+cwd = cwd.replace("/c:/", "c:/")
+```