Githug-Android/LevelsCompare.md

LevelsCompare

Comparison source: https://github.com/Gazler/githug/ at a613718 (release: 0.5.1, 2024-08-11).

Android source compared from app/src/main/java/solutions/tretter/githugandroid/levels/.

This file records the upstream Ruby setup and validation intent beside the Android Kotlin setup and validation. The Android port uses a real native Git sandbox for runtime state, but it exposes validation through RepoState, so some checks are expressed as equivalent state predicates rather than direct Ruby/Grit calls.

Setup Summary

Level	Upstream setup intent	Android setup intent	Parity / reason for difference
init	Creates git_hug, changes into it, and starts outside a Git repository.	Creates /sandbox/git_hug, starts the learner in it, and leaves it uninitialized.	Equivalent.
config	Initializes a repository.	Initializes a repository.	Equivalent.
add	Initializes repo, creates untracked README, renames branch to master.	Initializes repo with untracked README on master.	Equivalent.
commit	Initializes repo, creates and stages README.	Initializes repo with staged README.	Equivalent.
clone	No local repo setup.	Empty state.	Equivalent; validation is command/network simplified.
clone_to_folder	No local repo setup.	Empty state.	Equivalent; validation is command/network simplified.
ignore	Initializes repo, creates README.swp, clears global excludes in .git/config.	Initializes repo with .gitignore available for editing.	Differs slightly: Android does not need a swap file fixture because validation checks .gitignore content directly.
include	Initializes repo, creates first.a, second.a, lib.a, and clears excludes.	Initializes repo with .gitignore, lib.a, and main.a.	Same ignore-pattern lesson; Android uses a smaller fixture.
status	Initializes repo; stages config.rb, README, setup.rb, deploy.rb, Guardfile; leaves database.yml untracked.	Native setup now creates/stages the same five files and leaves database.yml untracked.	Equivalent.
number_of_files_committed	Initializes repo with committed modified files plus staged/untracked files, leaving exactly two files staged for commit.	Initializes equivalent file states with two staged files.	Equivalent.
rm	Initializes repo, commits deleteme.rb, then deletes it from the working tree.	Initializes repo with tracked deleted deleteme.rb.	Equivalent.
rm_cached	Initializes repo, stages .gitignore and deleteme.rb.	Initializes repo with both files staged.	Equivalent.
stash	Copies upstream fixture containing committed lyrics.txt plus local modifications.	Native setup creates the same committed lyrics text and the same trailing Hey! working-tree modification.	Equivalent.
rename	Initializes repo, commits oldfile.txt.	Initializes repo with tracked oldfile.txt and commit.	Equivalent.
restructure	Initializes repo with tracked about.html, contact.html, index.html.	Same tracked HTML files.	Equivalent.
log	Initializes repo with one commit whose message identifies the target.	Same one modeled commit.	Equivalent.
tag	Initializes repo with one commit.	Initializes repo with one tracked file and commit.	Equivalent.
push_tags	Creates local and remote repos, tag tag_to_be_pushed, and origin remote.	Native setup creates local/remote repo and tag; model records tag and remote.	Equivalent state projection.
commit_amend	Commits README, then creates untracked forgotten_file.rb.	Same committed README plus untracked forgotten_file.rb.	Equivalent.
commit_in_future	Initializes repo with staged README.	Initializes repo with staged README.	Equivalent setup.
reset	Commits README; stages to_commit_first.rb and to_commit_second.rb.	Same committed README plus both staged files.	Equivalent.
reset_soft	Commits README, then commits newfile.rb.	Same two commits and tracked files.	Equivalent.
checkout_file	Commits initial config.rb, then modifies it.	Same tracked modified config.rb.	Equivalent.
remote	Initializes repo and adds my_remote_repo remote.	Same remote in initialized repo.	Equivalent.
remote_url	Initializes repo and adds my_remote_repo and remote_location.	Same two remotes.	Equivalent.
pull	Initializes repo and adds remote URL https://github.com/pull-this/thing-to-pull.	Native setup creates local synthetic remote with a remote commit.	Deliberate offline equivalent to upstream network remote.
remote_add	Initializes repo with no origin remote.	Same.	Equivalent.
push	Creates divergent local and remote master histories: local has file3, remote has file4.	Native setup creates synthetic divergent origin with the same file/commit shape.	Equivalent.
diff	Copies upstream fixture with committed app.rb and one changed line.	Native setup creates the same committed app.rb and the same line 26 working-tree modification.	Equivalent.
blame	Copies upstream fixture where password line is authored by Spider Man.	Native setup creates the same config.rb content with the password line authored by Spider Man.	Equivalent.
branch	Initializes repo with one README commit.	Same.	Equivalent.
checkout	Initializes repo with one README commit.	Same.	Equivalent.
checkout_tag	Creates five commits and tags v1.0, v1.2, v1.5.	Same commit/tag shape.	Equivalent.
checkout_tag_over_branch	Creates same tags and also a branch named v1.2.	Same tag-plus-branch ambiguity.	Equivalent.
branch_at	Creates three commits on file1.	Same three modeled commits and native setup.	Equivalent.
delete_branch	Copies fixture with committed readme and delete_me branch at the same commit as master.	Native setup creates committed readme with master and delete_me pointing at it.	Equivalent.
push_branch	Creates local and remote repos with multiple branches and target test_branch.	Native setup creates synthetic remote and same branch intent.	Equivalent state projection.
merge	Copies fixture with file1 on master and file2 on feature.	Native setup creates master file1 and feature file2.	Equivalent.
fetch	Creates local master tracking origin/master; remote later gains new_branch with file1.	Native setup creates the same synthetic remote branch scenario; model starts with one fetched head.	Equivalent after latest update.
rebase	Copies fixture with divergent master and feature.	Native setup creates matching divergent master and feature.	Equivalent.
rebase_onto	Creates authors.md, bad wrong_branch, and readme-update branch needing --onto.	Native setup creates the same branch graph and files.	Equivalent setup.
repack	Initializes repo with one committed foo.	Same.	Equivalent.
cherry-pick	Copies fixture with master and new-feature; the desired README commit is not the branch tip.	Native setup creates the same branch shape: learner must cherry-pick the earlier README commit from new-feature.	Equivalent.
grep	Copies fixture with four TODO entries across app.rb and config.rb.	Native setup creates both source files with the same four TODO entries.	Equivalent.
rename_commit	Creates commits Initial commit, First coommit, Second commit.	Same typo commit sequence.	Equivalent.
squash	Creates initial hidden commit plus README and three squash-target README updates.	Same commit sequence.	Equivalent.
merge_squash	Creates master and long-feature-branch with multiple feature changes.	Native setup creates the same branch and file3 feature effect.	Mostly equivalent; Android currently validates less detail.
reorder	Creates commits Initial Setup, First commit, Third commit, Second commit.	Same order.	Equivalent.
bisect	Copies upstream Ruby fixture where ruby prog.rb 5 or make test identifies bad hash 18ed2ac.	Creates a native Git history with balance.txt, test-balance.sh, and known-good tag.	Intentional Android adaptation: no Ruby or make dependency, but real git bisect remains playable.
stage_lines	Commits initial feature.rb, then leaves two unstaged feature lines.	Initializes tracked feature.rb containing both feature lines.	Setup is close, but Android does not yet model partial staged vs unstaged hunks.
find_old_branch	Copies fixture whose active distractor branch is renamed to master, with other distractor branches and recoverable solve_world_hunger.	Native setup creates master, solve_world_hunger, cure_common_cold, and blowup_sun_for_ransom branches with matching working-tree files.	Equivalent.
revert	Creates commits First commit, Bad commit, Second commit.	Same commit messages.	Equivalent.
restore	Creates file1, file2, then creates and removes file3 so it is recoverable from reflog/history.	Native setup creates matching history and removes file3; model starts without file3.	Equivalent.
conflict	Copies fixture with master and mybranch conflict in non-empty poem.txt.	Native setup creates the conflicting poem history, leaving master with Categorized shoes by color and mybranch with the correct Sat on a wall line.	Equivalent setup.
submodule	Initializes empty repo.	Same.	Equivalent; network submodule operation is modeled.

Validation Summary

Level	Upstream validation intent	Android validation intent	Parity / reason for difference
init	repo.valid?	RepoState.initialized	Equivalent.
config	Prompted name/email must match user.name and user.email.	Validates nonblank user.name and user.email.	Deliberate UI difference: Android validates repository config state, not repeated prompt text.
add	README exists in index and is not untracked.	README is staged.	Equivalent.
commit	Repository has at least one commit.	Commit exists and README became tracked/unstaged.	Stricter but same lesson outcome.
clone	cloneme repo contains known commit 157b2b6....	Accepts exact clone command.	Deliberate mobile/network simplification; no external GitHub clone is performed in-game.
clone_to_folder	my_cloned_repo contains known commit.	Accepts exact clone-to-folder command.	Deliberate mobile/network simplification.
ignore	.gitignore contains *.swp.	.gitignore has a line equal to *.swp.	Equivalent.
include	.gitignore contains *.a and !lib.a.	Same two entries are present.	Equivalent.
status	User answers database.yml; setup has five staged files and one untracked file.	User answers database.yml; setup now mirrors staged files plus untracked database.yml.	Updated for parity.
number_of_files_committed	Prompt answer is integer 2.	Answer is 2.	Equivalent.
rm	deleteme.rb no longer has an unstaged deletion.	File removed from model or deletion staged.	Equivalent.
rm_cached	deleteme.rb is not staged and still exists.	deleteme.rb is unstaged, untracked, and not deleted.	Equivalent.
stash	stash@{0} exists and lyrics.txt has no working-tree changes.	At least one stash and no staged files.	Slightly looser; Android does not model unstaged tracked dirt separately after stash.
rename	oldfile.txt deleted unstaged and newfile.txt added.	newfile.txt exists and live oldfile.txt is gone.	Equivalent for accepted solutions.
restructure	HTML files are deleted at root and added under src/.	All three src/*.html files exist and no live root HTML files remain.	Equivalent.
log	Prompt answer matches latest commit hash prefix.	Answer matches the modeled commit hash.	Equivalent within Android's deterministic commit model.
tag	First tag is new_tag.	new_tag exists.	Equivalent.
push_tags	Remote tag list contains tag_to_be_pushed.	tag_to_be_pushed is in pushedTags.	Equivalent state projection.
commit_amend	One commit and amended commit contains two files.	One commit and forgotten_file.rb is tracked.	Equivalent.
commit_in_future	Commit authored date is in the future.	At least one commit has an author timestamp later than the current system clock.	Equivalent.
reset	to_commit_second.rb exists but is unstaged; to_commit_first.rb remains staged.	Same staged/unstaged split with one commit.	Equivalent.
reset_soft	newfile.rb exists, is staged, and commit count is one.	Same.	Equivalent.
checkout_file	config.rb no longer modified and commit count remains one.	config.rb content equals initial content.	Equivalent.
remote	User answers my_remote_repo.	Answer is my_remote_repo.	Equivalent.
remote_url	User answers URL matching https://github.com/githug/not_a_repo/?.	Answer is exact URL without trailing slash.	Slightly stricter; can be relaxed if trailing slash should be accepted.
pull	Latest commit hash is 1797a7c.	Remote file is present, origin/master fetched, and commits advanced.	Equivalent local synthetic remote outcome.
remote_add	git remote -v contains https://github.com/githug/githug.	origin remote equals that URL.	Equivalent and slightly stricter on remote name.
push	Local master and origin/master have four identical commits.	origin/master was pushed, four files are present, and commit count is at least four.	Equivalent user outcome; Android tracks pushed ref instead of comparing remote commit IDs.
diff	Answer is changed line number 26.	Answer is 26.	Equivalent.
blame	Answer equals author of known password commit (Spider Man).	Answer is Spider Man.	Equivalent with deterministic Android fixture.
branch	Branch test_code exists.	test_code exists and current branch remains master.	Slightly stricter to prevent solving by checkout side effects.
checkout	Current branch is my_branch.	Current branch is my_branch and branch exists.	Equivalent.
checkout_tag	HEAD subject is "Some more changes" with five commits.	HEAD is at tag v1.2.	Equivalent in Android tag model.
checkout_tag_over_branch	Same as checkout_tag; must choose tag, not branch.	HEAD is at tag v1.2.	Equivalent in Android tag model.
branch_at	test_branch exists and excludes "Updating file1 again".	test_branch points at commit index 2.	Equivalent.
delete_branch	delete_me branch no longer exists.	Same.	Equivalent.
push_branch	Remote has pushed test_branch but not all branches.	origin/test_branch pushed and master/other not pushed.	Equivalent.
merge	file1 and file2 exist.	Current branch is master, a merge action occurred, and file2 is tracked.	Deliberately stricter than upstream to avoid git switch feature falsely solving on Android.
fetch	Local branch count is one and .git/FETCH_HEAD has two entries.	branches.size == 1, fetchHeadCount == 2, and no recorded pull action.	Mostly parity; Android adds the pull guard because real Git can leave two FETCH_HEAD lines after git pull, while the exercise wording explicitly says fetch without merging.
rebase	feature commit messages are add feature, add content, init commit, and old hash changed.	Current branch is feature and modeled commit messages match.	Equivalent, except Android does not compare the old hash.
rebase_onto	readme-update has four commits, excludes "Wrong changes", and preserves authors.	Current branch is readme-update and rebase-onto action occurred.	Known gap: Android validation is looser than upstream content/commit checks.
repack	git count-objects -v includes packed/pruned object evidence.	repack action recorded.	Equivalent action-level validation; Android does not model object database packing stats.
cherry-pick	Top commits are "Filled in README..." then "Added fancy branded output".	Same commit message order plus README.md tracked.	Equivalent.
grep	Answer is TODO count 4.	Answer is 4.	Equivalent.
rename_commit	Parent commit message is corrected to First commit.	No coommit remains and First commit exists; the in-app rebase editor uses the subject text on a reword line as the replacement message.	Equivalent outcome with a single mobile editor step.
squash	Commit count is two.	Commit count at most two and "Adding README" remains.	Slightly stricter on preserving the base README commit.
merge_squash	Commit count is three and all long-feature changes are included.	Squash action recorded and a commit exists.	Known gap: Android does not yet verify all squash file/content effects.
reorder	git log subject order matches Third.*Second.*First.*Initial.	Modeled commit order becomes First, Second, Third.	Equivalent relative to Android's oldest-first commit list.
bisect	Answer is hash prefix 18ed2ac after using Ruby/make fixture.	Learner can run git bisect start, mark HEAD bad and known-good good, run git bisect run ./test-balance.sh, then answer the last good commit hash.	Same bisect lesson, different fixture and final answer target to keep the Android flow clear without Ruby/make.
stage_lines	Staged diff contains first feature line; unstaged diff contains second feature line.	feature.rb is staged.	Known gap: Android does not yet model partial hunk staging.
find_old_branch	Current branch is solve_world_hunger.	Same.	Equivalent.
revert	More than three commits and a revert of "Bad commit" exists.	A commit message starts with Revert.	Slightly looser; sufficient for current fixture.
restore	file3 exists.	file3 is tracked.	Equivalent.
conflict	On master, merge commit has two parents, conflict markers removed, both poem lines preserved.	Requires the latest commit on master to be a two-parent merge commit, conflict markers removed, and the correct Sat on a wall poem line preserved.	Equivalent.
submodule	githug-include-me directory exists, has README, and is a gitlink/submodule.	submodules contains githug-include-me URL.	Equivalent state projection.

Focused Source-To-Android Checks

fetch

Upstream Ruby (levels/fetch.rb)	Android Kotlin (FetchLevel.kt)
Counts local branches with repo.branches.size.	Uses repo.branches.size.
Counts .git/FETCH_HEAD lines after fetch; success requires num_remote == 2.	GitRuntime now reads .git/FETCH_HEAD into RepoState.fetchHeadCount; success requires fetchHeadCount == 2.
Success requires exactly one local branch and two fetched heads.	Success requires exactly one local branch and two fetched heads. Android also rejects a recorded pull action to preserve the exercise instruction "without merging" under native Git behavior.

status

Upstream Ruby (levels/status.rb)	Android Kotlin (StatusLevel.kt)
Stages config.rb, README, setup.rb, deploy.rb, and Guardfile.	Native setup now creates and stages those same five files.
Leaves database.yml untracked.	Leaves database.yml untracked.
Validates answer database.yml.	Validates answer database.yml.

merge

Upstream Ruby (levels/merge.rb)	Android Kotlin (MergeLevel.kt)
Validates File.exists?("file1") && File.exists?("file2").	Validates master, a recorded merge action, and tracked file2.
Upstream is filesystem-only and loose.	Android is intentionally stricter because git switch feature otherwise produces the same visible file state and falsely solves the level.

Follow-Up Gaps

These are the remaining known non-parity items that need additional model support if exact upstream validation is required:

• stage_lines: model partial staged vs unstaged hunks.
• merge_squash: verify the exact squashed file/content effects.
• rebase_onto: verify final commit count/content and removal of "Wrong changes".
• clone, clone_to_folder: current Android behavior intentionally avoids real network-dependent validation.

The upstream contribute call to action is intentionally not implemented as a level because it asks learners to contribute to the original GitHug repository rather than teaching or validating a Git operation.