git: match native agent workflows

userland/git/README.md

@@ -25,7 +25,10 @@ The script checks that the component imports only WASI interfaces.
 It creates separate native and WASI repositories under `/tmp/p1-git/`.
 It fixes both identities and timestamps.
 It compares stdout and exit codes without filtering command output.
-Initialization and worktree listings compare exit codes only because their paths differ.
+The initialization check normalizes only its repository path.
+Worktree listings compare exit codes only because their paths differ.
+Mutation checks also compare repository state through native Git on both fixtures.
+They compare status, commit IDs, parents, authors, diffs, and references.
 The script retains its fixtures for inspection.
 
 `wasmtime run` needs `-S http`, including for local operations.
@@ -34,6 +37,48 @@ The component uses WASI's `exit-with-code`, not a custom host import.
 The world host must enable that optional WASI function.
 The tests pass explicit `-C` paths.
 
+## Agent command forms
+
+The comparison suite covers per-command `-c key=value` overrides and quiet local commands.
+It checks multiple revisions, detached status, branch deletion messages, and merge commit output.
+It also checks these forms:
+
+- `status -sb` and `status --porcelain=v1`.
+- `log -n`, `--oneline`, `-p`, `--stat`, and one literal path after `--`.
+- `log --format` and `--pretty=format:` with `%H %h %s %an %ae %ad %d`.
+- `show --stat`, `show HEAD:path`, and merge commits without a combined diff.
+- `diff HEAD~1`, `diff A..B`, `--name-only`, `--name-status`, and one literal path after `--`.
+- `branch -a`, `-d`, `-D`, `-m`, and `--show-current`.
+- `checkout -b`, `switch -c`, and `merge --no-ff`.
+- `rev-parse --short HEAD`, `ls-files`, and `config --get`.
+- Quiet `init`, `commit`, branch deletion, `checkout`, `switch`, `merge`, and `rebase`.
+- `init` in an existing repository without replacement of HEAD or configuration.
+- `reset --soft`, `reset --hard`, mixed `reset HEAD~1`, and `reset HEAD <file>`.
+- `commit --amend -m`, `commit --amend --no-edit`, and `commit -F`.
+- `checkout <file>`, `checkout -- <file>`, `restore <file>`, and `restore --staged`.
+- Bare `stash`, `stash push`, `-m`, `list`, `pop`, `apply`, and `drop`.
+- Quiet stash push, pop, and drop.
+- Lightweight tags, `tag -a -m`, bare `tag`, `--list`, and `-d`.
+- `remote -v`, `add`, `remove`, `set-url`, and `get-url`.
+- Clean `cherry-pick` and conflict resolution through `--continue` or `--abort`.
+
+The log applies its path filter before its count limit.
+Stashes use ordinary Git commits and the `refs/stash` reflog.
+Stash accepts only the listed subcommands.
+Cherry-pick conflicts use `CHERRY_PICK_HEAD` and `MERGE_MSG`.
+
+### Unsupported forms
+
+These forms return a usage error with exit code 129 and empty stdout.
+The suite checks the usage error instead of native Git's successful operation.
+
+- `log --graph --oneline --all`.
+- `show` of a merge that changes the same path relative to every parent, which requires a combined diff.
+
+The CLI supports textual diffs and literal paths, not Git's complete pathspec language.
+The format options support the placeholders above, not Git's complete pretty-format language.
+The suite compares stdout and exit codes. It does not compare stderr text.
+
 ## Local smart-HTTP test
 
 Build the native fixture server: