submarine/docs/actions.md

Actions (draft)

Status: Restore (key x, D23), Switch branch (key b, D24) and Update pin (key u, D29) are implemented. Stage pin was dropped (D29).

Principle

Offer as few actions as possible, but enough to work with submodules. submarine shows what differs from what git records. The actions resolve such a difference in one of two directions:

Action	Direction	Key
Restore	The worktree follows the recorded state	x
Switch branch	Both: the branch tip is recorded, then restored to	b
Update pin	Both: a switch to the tip of the pin's ref	u

There is nothing else for now. Committing and pushing are done outside submarine. Recording a commit made in a submodule is a switch to its branch (b); a commit on no branch must get one first.

Restore

Makes the selected repository, and everything below it, exactly what git records. It works on any submodule and on the superproject (header selected). Restoring the superproject gives the exact project that the current root commit specifies, with the pins you have staged.

Target

Selected	Target commit	Branch
Superproject	HEAD	stays on the current branch
Submodule	The pin in the parent's index (what the UI shows as Pinned); with a staged pin you choose, see below	see Branches
Nested submodule, during the recursion	The gitlink in the restored parent's index	as for a submodule

Staged pins are kept, at every depth. A staged pin is a decision, not drift. Each repository's files are reset to its HEAD, but its staged pins stay in its index, and the submodules below are restored to them. So a nested submodule with a staged pin and uncommitted changes keeps the pin and is reset to it; its changes are discarded (and listed in the question).

Choosing the pin. If the selected submodule has a staged pin itself, x first asks which pin to restore to:

Restore libs/staged to  s staged pin · c committed pin (unstages it)     any other key cancels

• s: the staged pin, which stays staged.
• c: the committed pin (the gitlink in the parent's HEAD). The parent's index is set back to it, which is how a pin is unstaged in submarine.

The loss check then runs for the chosen pin (the two can differ: a staged commit that exists only locally is lost by c, not by s).

Two exceptions, where a staged pin is not kept:

• The repository moves. If a repository is off its pin, restore checks out another commit; staged pins in its own index belonged to the old one. They are counted as a loss (2 staged pins), so the question appears. Its submodules follow the target commit's tree.
• An added, not yet committed submodule is no staged pin: its .gitmodules entry is reset with the other files. Its directory then counts as an untracked file.

Postconditions

After a successful restore of repository R with target T:

1. R's HEAD is T. The index and the worktree equal T's tree, except for the staged pins that were kept. No modified, added, removed or conflicted files remain.
2. No in-progress operation remains in R: merge, rebase, cherry-pick, revert.
3. No untracked files or directories remain in R. This includes leftover directories of submodules that T no longer has (untracked repository). Ignored files are kept.
4. Every submodule that R's index records is present and initialized, even if it was never initialized, is inactive (submodule.<name>.active) or has update = none / merge / rebase configured. Its URL comes from T's .gitmodules (synced into the config).
5. Each of those submodules is restored the same way, with its gitlink in R's index (T's, or a kept staged pin) as its target, recursively at any depth.

So the subtree shows in sync everywhere, except for states restore does not change: unpushed, behind/ahead of the ref, and detached HEAD on pin where no branch is at the pin (see Branches).

The recursion follows T, not the tree loaded in the UI. A submodule that is only in T (for example, after switching branches) is initialized. A submodule that is only on disk is deleted as an untracked directory.

Branches

• Superproject: stays on its branch. The branch is not moved, since the target is its own HEAD.

• Submodule on the pin: if HEAD is a branch that points at the target, the branch stays checked out.

• Submodule off the pin: HEAD is detached at the target. The branch that was checked out is not moved, so its commits stay on it.

• Submodule detached at the target (after the step above, or because it was already so, also when it was in sync): HEAD is put on a branch whose tip is the target, the first that fits of (D28):

  1. a local branch tracking the ref the UI shows (or named like it), e.g. local main tracking origin/main, also when the pin is behind or ahead of the ref;
  2. the ref itself, if its tip is the target and no local branch has its name: the local branch is created, tracking it;
  3. any other local branch, the first alphabetically;
  4. any other remote branch whose name no local branch has, created as a tracking branch; the ref's remote first, then alphabetically.

  If git refuses one (checked out in another worktree, a name conflict), the next is tried. If none fits, HEAD stays detached.

Restore never moves or deletes a branch. A local branch that is behind or ahead of its remote branch is no candidate and is not fast-forwarded. The only branches restore creates are tracking branches for remote branches at the target, in steps 2 and 4.

What can be lost

Restore discards work. The things it can lose:

Lost	Where it comes from
Changed files	modified, added, removed, renamed files (changed)
Untracked files	changed (untracked)
Conflicts and in-progress operations	conflict; merge, rebase, cherry-pick, revert state
Commits	A detached HEAD off the pin whose commits are on no branch, tag or remote ref (only the reflog still has them)
Staged pins	Staged pins in a repository that restore moves to another commit (see Target)
Repositories	An untracked directory that is a repository with its own .git directory (a clone that was never added as a submodule). Its commits may exist nowhere else. A removed submodule whose git directory is absorbed into .git/modules loses only its worktree. Its objects stay

Nothing else is lost. Branches, stashes, remote refs, ignored files and absorbed submodule git directories stay.

Confirmation

Restore asks only if something would be lost. Never asking is unsafe (git clean -ff deletes repositories that exist nowhere else, and nothing undoes a restore); always asking puts a question on the harmless, common cases (off pin, missing, a staged pin) and teaches a reflexive y.

• Nothing would be lost: restore runs at once.

• Something would be lost: a line above the footer says what is discarded, summed over the whole subtree on disk:

  Restore src/app? Discards 7 changed files in 3 repositories, 2 commits on no branch, 1 untracked repository.   y restore · n cancel
  

  y runs it, any other key cancels.

• The state can't be read for a repository: it is counted as n repositories of unknown state and needs the same y.

The check reads the disk at the moment of the keypress (RestoreLoss), not the loaded statuses, so loading or stale statuses don't matter. Nothing is lost that is not in the table above; ignored files are never touched.

Network

A restore may need objects that are not on disk: a submodule that was never cloned (no git directory in .git/modules), or a target commit that was never fetched. Restore may clone and fetch, but only what is missing, non-interactively (GIT_TERMINAL_PROMPT=0, ssh BatchMode) and with a timeout. If the commit is on no remote, restore fails with commit … is not available on any remote. This is the one place besides f that uses the network (decision D23).

Running, progress and errors

• A line above the footer shows checking … and then restoring … with a spinner. Only one restore runs at a time; pressing x meanwhile flashes wait for the restore of src/app to finish. Everything else keeps working.
• A running fetch does not block a restore.
• Done: flash restored src/app; the app reloads the tree and all statuses, because the structure can have changed.
• Failure: the restore stops with git's message, shown in red above the footer (restore of src/app failed: …) until the next key. Restore is idempotent, so it can be run again after fixing the cause. Repositories that were restored before the failure stay restored.

Implementation note

git.Provider.Restore (internal/submodule/git/restore.go) walks the repositories itself, top-down; the children of a repository run concurrently, bounded by the provider's semaphore. For each repository (T = target) it runs, with -c submodule.recurse=false:

cat-file / fetch --all            # only if T is missing locally
rebase|cherry-pick|revert --quit  # whichever is in progress; --quit, not --abort: no ref moves
checkout --force --detach T       # only if HEAD is not T, so a branch is never moved
reset --hard                      # also ends a merge
update-index --cacheinfo …        # put the staged pins back (only if HEAD did not move)
clean -ffd                        # -ff: untracked repositories too; ignored files stay
submodule sync
submodule update --init --checkout --force -- <not yet initialized children>
# then every gitlink of the index (ls-files -s) is restored the same way

--checkout overrides submodule.<name>.update, and the explicit paths override submodule.<name>.active, so no child module is skipped.

For a submodule, after submodule sync, attachBranch puts a detached HEAD on a branch: symbolic-ref -q HEAD (on a branch: done), for-each-ref --points-at=T refs/heads refs/remotes (no branch at T: done), then the ref is resolved like Status does, and the first candidate (see Branches) that switch / switch -c <local> --track <remote> accepts wins. The branch checked out before the restore is passed to the ref resolution. A child's .gitmodules branch is read once per parent.

With c the parent's index gets the committed pin first (update-index --cacheinfo in the parent).

RestoreLoss (lossOf) follows the repositories on disk: per repository status (without submodules), the in-progress state files, and rev-list --count HEAD --not --branches --tags --remotes if HEAD is not the target. A directory in the untracked list is searched for .git directories (a standalone repository); an absorbed submodule leaves only a .git file and loses just its worktree.

Switch branch

Moves the selected repository to another branch, in one step: the tip of the branch becomes the pin, and the repository is restored to it.

The popup

b opens a popup in the middle of the screen: a search line on top, below it the branches of the selection, local ones first, then remote ones (origin/…), each group with the newest tip first. Each row shows the name (* marks the checked-out branch), the short SHA and the age of the tip. The list is read from the disk; fetch (f) is what brings new remote branches.

Key	Effect
text	Filters: every word must be in the name, case-insensitive. The selection stays on its branch if it still matches
↑ ↓, pgup pgdn	Select
enter	Switch to the selected branch
esc	Close

Mouse: a click on a branch switches to it (like enter), the wheel moves the selection, a click outside the popup closes it; a click on the title, the search line or an empty row does nothing. Everything else is ignored while the popup is open. A header selection switches the superproject.

Effect

For a submodule, with the tip T the list showed:

1. The parent's index records T as the pin (a staged pin; if T is the committed pin, the index equals HEAD again).
2. The submodule, and everything below it, is restored to T.
3. HEAD is put on the branch (the branch name is the local one):
   • a local branch: checked out;
   • a remote branch origin/feat: the local branch is the one checked out before if it tracks origin/feat (e.g. dev), else feat. It is created, tracking it, if it does not exist; if it exists at T it is checked out; if it is only behind T (an ancestor of it) it is fast-forwarded to T and checked out (D29); if it has commits of its own, or is checked out in another worktree, it is not moved and HEAD stays detached at T.

For the superproject step 1 is left out: the branch is checked out via the restore, so its submodules follow the pins of the new commit (staged pins of the old state are lost, and counted).

Staging comes first, so a failed restore can be repeated with x. If the branch moved since the list was read (a fetch), the switch aborts with origin/feat moved; open the list again; the staged SHA is always the one shown.

Confirmation, network, errors

As for restore: the loss is read from the disk and the question (Switch src/app to origin/feat? Discards … y switch · n cancel) appears only if something would be lost. A submodule that is not initialized can't be switched (src/app is not initialized; restore it first). Network: only what is missing below, like restore. Lines above the footer: checking …, switching src/app to origin/feat…; flash switched src/app to feat (or … to origin/feat (detached: local feat can't be fast-forwarded)); failure switch of src/app to origin/feat failed: …, until the next key. One restore or switch runs at a time.

Implementation note

git.Provider.Switch (internal/submodule/git/switch.go): verify the ref is still T; update-index --cacheinfo in the parent; restoreRepo (see restore); then switch / switch -c <local> --track <remote-branch>; a local branch behind T is first moved with merge-base --is-ancestor <local> T, a look at worktree list --porcelain and update-ref refs/heads/<local> T <old> (which fails if the branch moved meanwhile). The restore leaves HEAD of the switched repository alone (Switch puts it on the chosen branch); the submodules below it are attached as in a restore. SwitchLoss is lossOf with T as the target. Branches is one for-each-ref, without the origin/HEAD symref.

Update pin

Moves the pin of a submodule to the tip of its ref, the branch the row shows (origin/main ↓2). It is a switch to that branch, with the tip the row shows: nothing is fetched, so u gives exactly the commits the row counts. f is what brings newer ones.

On the superproject the pin is HEAD and the ref is the upstream of its branch (the header's main ↓1): u fast-forwards the branch to it, like git pull --ff-only, and restores the submodules to the pins of the new commit.

Available when

All of:

• it is initialized and its state is loaded;
• its ref is a remote branch (not a tag, a SHA or a local branch) and has a tip; for the superproject: its branch has an upstream;
• the pin is behind the ref and not ahead (Behind > 0, Ahead == 0). A diverged pin (↑n↓m) is left to b: moving it would drop the pin's own commits from the record.

Effect

The same as switching to the ref: the tip is staged as the pin, the submodule and everything below it are restored to it, and HEAD is put on the local branch. A local branch that is only behind is fast-forwarded, so the common case (local main at the old pin) ends on main. A checked-out branch that tracks the ref under another name (dev tracking origin/main) is the one used, so the update stays on it. For the superproject staged pins are lost, as in a switch (and counted).

If the ref no longer points at the tip the row showed (a fetch meanwhile), nothing happens: can't update src/app: origin/main moved; check the new state. The watcher has updated the row by then; u again takes the new tip.

Confirmation, lines, errors

As for switch: the question appears only if something would be lost (Update src/app to origin/main? Discards … y update · n cancel). Lines above the footer: checking src/app…, updating src/app to origin/main…; flash updated src/app to main; failure update of src/app to origin/main failed: ….

Implementation note

The UI only: startPinUpdate (internal/tui/pinupdate.go) reads the branches (Switcher.Branches), takes the one named like Pin.Ref, checks that its tip still starts with the abbreviated Status.Tip.SHA, and then runs the switch flow with it (SwitchLoss, Switch).

Keys and palette

All three are submodule keys (keyMap.Submodule), shown in the detail pane's palette, or in the footer when the pane can't show it. They are always offered, the palette is static: restore is idempotent, and u says why it can't update.

Key	Action	Pressed when not possible (flash)
x restore	Restore the selection	this data source can't restore (mock); wait for the restore of … to finish
b switch branch	Switch branch	this data source can't switch branches; wait for the restore of … to finish; src/app is not initialized; restore it first
u update pin	Update pin	this data source can't update pins; wait for the restore of … to finish; the superproject has no upstream branch; src/app is still loading; src/app is not initialized; restore it first; the pin of src/app is not on a branch; the pin of src/app has diverged from origin/main; b switches the branch; the pin of src/app is ahead of origin/main; src/app is up to date with origin/main (the superproject without the pin of); after the check can't update src/app: main is a local branch; b switches to it

R would sit next to r (reload), a dangerous mix-up for a destructive action, hence x.

Testing

• Provider (restore_test.go), on fixtures from scripts/make-fixture.sh: a restored superproject is exact (every repository clean, submodule status --recursive without prefixes, libs/missing initialized), branches are not moved, ignored files survive, a merge and a rebase in progress end, a standalone clone and a removed submodule's directory are deleted, a missing submodule is cloned again, update = none and inactive submodules are restored, an unavailable commit is reported. A detached submodule ends on the local branch tracking the ref, else on the ref created as a tracking branch (before other branches at the pin), else on the first local branch; a local branch elsewhere is not moved; a checked-out branch stays; a branch of another worktree is skipped; nested submodules are attached too. The loss is empty for off pin, missing and unpushed submodules, counts files, nested changes, merges, detached commits (not those on a branch) and standalone repositories.
• UI (internal/tui/restore_test.go): restores at once without a loss, asks with one (y restores, anything else cancels), the mock can't restore.
• Switch: provider (switch_test.go): list without origin/HEAD, local first; a remote pick stages the tip and creates a tracking branch; a local branch that is only behind is fast-forwarded; one with commits of its own, or checked out in another worktree, is not moved; a moved ref aborts; the superproject switch ends exact; the loss is the restore's. Picker (branches_test.go): filter, selection, scrolling. UI (switch_test.go): opens, filters, enter switches, asks with a loss, esc closes, the mock can't.
• Update pin: UI (pinupdate_test.go): switches to the tip of the ref, asks with a loss, aborts if the ref moved, refuses (with its flash) a pin that is up to date, ahead, diverged, on a tag, on a local branch or not initialized; updates the superproject, not one without an upstream. Provider: the superproject's branch is fast-forwarded; a checked-out branch that tracks the remote branch under another name is kept.
• By hand in tmux on a fixture, see architecture.md.

Open questions

Decided for restore: ignored files are kept (clean without -x); a submodule is restored to the index gitlink, so a staged pin is its target and survives; restore may clone and fetch what is missing; the key is x; it asks only if something would be lost.

Open (update pin): updating several submodules at once (on the superproject or a collapsed parent), deliberately left out for now.