fix(terminal): git reads real files, and every output matches Git 2.56

[thierryvm]

Summary

The simulated git kept a list of file names. That produced three visible faults:

• git add accepted files that do not exist and printed staged:, which real git never writes.
• git status never saw a modified or deleted file.
• git diff always printed the same invented example.

The Git lessons and the reference page taught against that simulation.

Git now works on the simulated files themselves. Every expected value in the new tests was printed by Git 2.56 on a copy of the lesson project.

Model (src/app/data/commands/gitTree.ts is new):

• The state holds the repository path, the HEAD tree, the index, file modes and stash entries.
• gitTree.ts provides:
  • reading the working tree;
  • .gitignore rules, including ! patterns and directory rules;
  • Myers diff with git's hunk grouping and function-context headers;
  • SHA-1 blob ids. index 7d825c5..6827029 matches real git byte for byte.
• The simulator stores text without its final newline, following the convention wc already uses. Git reads each file with that newline.

Commands. These follow git's wording, exit codes and option parsing (-rf, -am, -uno, --source HEAD~1):

• status: long, -s, -b, --porcelain, -u.
• add: ., paths, -A, -u, -f, -n, -v. Ignored and missing paths are refused.
• rm: refuses to lose work, and removes the directories it empties.
• restore: --staged, --source.
• commit: root commit, stats, create and delete mode lines, -a, -q, --allow-empty, -m without a value.
• diff: HEAD, --staged, --name-only, --name-status, --numstat, --shortstat, -U.
• check-ignore: -v, -q, -n.
• reset: --soft, --mixed, --hard. Paths only change the index; --hard and --soft with paths are refused.
• stash: -m, pop and apply the delta, overwrite conflicts, drop, clear.
• init -b and init -q, and clone -b.

Commands that are still not simulated say so explicitly: add -p, diff --stat, branch-to-branch diff, commit --amend, stash -u.

Lessons and reference

• ~/projets in Git lessons is now a real repository, with .git/, a .gitignore that keeps .env out, and index.html. The lesson warns that git add . takes .env; the prepared repository now protects it.
• git diff & .gitignore starts from a real change (new gitRepoWithChange setup).
• Theory blocks show real output:
  • status, status -s and diff;
  • check-ignore -v;
  • the refusal to add an ignored file;
  • the root commit.
• Clone examples each use their own directory, and the fork workflow now runs cd projet before git remote add.
• Reference: the SSH clone example cloned the same repository into an existing folder. It now clones alice/site.git.
• Theory gaps: 158 → 148, none added.

UI

• New output line type removed: standard output rendered in --github-red, used for deleted diff lines and unstaged or untracked paths. It is routed to stdout, so pipes and redirections keep it.
• The lesson terminal now remounts when the environment changes. Setups now depend on the environment, for Windows file modes and .git/config, and the state is only read on mount (ui-auditor W1).

Gates

• curriculum-validator: 0 CRITICAL.
• ui-auditor: 0 CRITICAL. W1 (remount on environment change) is fixed. W2: red is shared with errors; the - prefix and deleted: carry the meaning in text.
• terminal-fidelity-auditor:
  • About 600 comparisons against real git; P1 findings fixed in this PR.
  • Remaining items are listed below for the next Git PR: log options, renames, mode changes, nested .gitignore, pathspec globs, branch/checkout/config wording, ls on empty directories, grep -c.
  • Incident: the auditor ran a lesson's code index.html in a real shell and opened two VS Code windows. The agent's deny rules will be tightened in a follow-up docs(agents) commit.
• feature-dev:code-reviewer: 4 IMPORTANT, all fixed, plus two below-threshold suspicions that real git confirmed:
  • hunk headers typed info were lost in pipes;
  • reset <commit> -- <path> moved HEAD;
  • git init -b dev dev lost the branch name;
  • long options did not take a space-separated value;
  • check-ignore reported tracked files;
  • git rm -r left empty directories.

Test plan

• tsc, eslint src, full vitest, vite build.
  • Live-Supabase integration tests time out under full-suite concurrency. This flakiness is known; they pass when run serially (39/39).
• New src/test/gitFidelity.test.ts (52 tests, real Git 2.56 values), updated engine and setup tests.
• Local Chrome check:
  • Desktop 1280: git diff lesson with red/green lines and exercise validated; git status, git add .env refused, check-ignore -v, .git in ls -a.
  • Mobile 390: status and diff, no horizontal overflow.
  • Windows switch: fresh PowerShell session, script.sh committed as 100644.
  • No console errors.
• CI, Sourcery, preview smoke test, merge, production check.

🤖 Generated with Claude Code

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Project	Deployment	Actions	Updated
terminal-learning	Ready	Preview	Sep 29, 2026 5:41pm UTC

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