ts1261-filename-casing

# TS1261 (filename casing) ## Problem Diagnostic 1261 in `typescript` (`Already_included_file_name_0_differs_from_file_name_1_only_in_casing`): one path comes from an import, another from `include` / program — same file on a case-insensitive disk, different casing in the string. Typical cause: git tracks `fooBar.ts` but imports `./FooBar`; or a case-only rename left the index with old casing. ## Fix Canonical name = what imports use (and consistent Pascal/camel across repo). **Case-insensitive FS (macOS default, Windows):** case-only renames need a **temporary** middle name so git and the filesystem both update. ```bash cd path/to/dir git mv WrongCaseName.ts _tmp_rename.ts git mv _tmp_rename.ts RightCaseName.ts ``` Then `npm run compile`. ## Why not a single `git mv`? `git mv a.ts A.ts` often no-ops or fails when `a` and `A` resolve to the same path — the two-step move is the reliable fix. ## `git rm` / index Goal is an index entry whose path **string** matches imports. `git rm --cached <wrong-cased-path>` removes that index entry; you still must put content on disk under the **right** cased name (again: use intermediate `mv` on case-insensitive FS). Two-step `git mv` updates index + working tree in one workflow without a detached delete step. ## Verify - `npm run compile` - `git ls-files path/to/dir | grep -i <basename>` shows one line, casing matches imports ## Checklist - [ ] Read TS1261 lines: identify both casing spellings - [ ] Choose spelling that matches existing imports - [ ] Two-step `git mv` if case-only change on case-insensitive FS - [ ] Re-run compile