WIP: new command: gs commit pick

.changes/unreleased/Added-20241228-193338.yaml

@@ -0,0 +1,6 @@
+kind: Added
+body: >-
+  New 'commit pick' command allows cherry-picking commits
+  and updating the upstack branches, all with one command.
+  Run this without any arguments to pick a commit interactively.
+time: 2024-12-28T19:33:38.719477-06:00

commit.go

@@ -3,5 +3,6 @@ package main
 type commitCmd struct {
 	Create commitCreateCmd `cmd:"" aliases:"c" help:"Create a new commit"`
 	Amend  commitAmendCmd  `cmd:"" aliases:"a" help:"Amend the current commit"`
+	Pick   commitPickCmd   `cmd:"" aliases:"p" help:"Cherry-pick a commit"`
 	Split  commitSplitCmd  `cmd:"" aliases:"sp" help:"Split the current commit"`
 }

commit_pick.go

@@ -0,0 +1,184 @@
+package main
+
+import (
+	"cmp"
+	"context"
+	"fmt"
+
+	"github.com/charmbracelet/log"
+	"go.abhg.dev/gs/internal/git"
+	"go.abhg.dev/gs/internal/spice"
+	"go.abhg.dev/gs/internal/spice/state"
+	"go.abhg.dev/gs/internal/text"
+	"go.abhg.dev/gs/internal/ui"
+	"go.abhg.dev/gs/internal/ui/widget"
+)
+
+type commitPickCmd struct {
+	Commit string `arg:"" optional:"" help:"Commit to cherry-pick"`
+	// TODO: Support multiple commits similarly to git cherry-pick.
+
+	Edit bool   `default:"false" negatable:"" config:"commitPick.edit" help:"Whether to open an editor to edit the commit message."`
+	From string `placeholder:"NAME" predictor:"trackedBranches" help:"Branch whose upstack commits will be considered."`
+}
+
+func (*commitPickCmd) Help() string {
+	return text.Dedent(`
+		Apply the changes introduced by a commit to the current branch
+		and restack the upstack branches.
+
+		If a commit is not specified, a prompt will allow picking
+		from commits of upstack branches of the current branch.
+		Use the --from option to pick a commit from a different branch
+		or its upstack.
+
+		By default, commit messages for cherry-picked commits will be used verbatim.
+		Supply --edit to open an editor and change the commit message,
+		or set the spice.commitPick.edit configuration option to true
+		to always open an editor for cherry picks.
+	`)
+}
+
+func (cmd *commitPickCmd) Run(
+	ctx context.Context,
+	log *log.Logger,
+	view ui.View,
+	repo *git.Repository,
+	store *state.Store,
+	svc *spice.Service,
+) (err error) {
+	var commit git.Hash
+	if cmd.Commit == "" {
+		if !ui.Interactive(view) {
+			return fmt.Errorf("no commit specified: %w", errNoPrompt)
+		}
+
+		commit, err = cmd.commitPrompt(ctx, log, view, repo, store, svc)
+		if err != nil {
+			return fmt.Errorf("prompt for commit: %w", err)
+		}
+	} else {
+		commit, err = repo.PeelToCommit(ctx, cmd.Commit)
+		if err != nil {
+			return fmt.Errorf("peel to commit: %w", err)
+		}
+	}
+
+	log.Debugf("Cherry-picking: %v", commit)
+	err = repo.CherryPick(ctx, git.CherryPickRequest{
+		Commits: []git.Hash{commit},
+		Edit:    cmd.Edit,
+		// If you selected an empty commit,
+		// you probably want to retain that.
+		// This still won't allow for no-op cherry-picks.
+		AllowEmpty: true,
+	})
+	if err != nil {
+		return fmt.Errorf("cherry-pick: %w", err)
+	}
+
+	// TODO: cherry-pick the commit
+	// TODO: handle --continue/--abort
+	// TODO: upstack restack
+	return nil
+}
+
+func (cmd *commitPickCmd) commitPrompt(
+	ctx context.Context,
+	log *log.Logger,
+	view ui.View,
+	repo *git.Repository,
+	store *state.Store,
+	svc *spice.Service,
+) (git.Hash, error) {
+	currentBranch, err := repo.CurrentBranch(ctx)
+	if err != nil {
+		// TODO: allow for cherry-pick onto non-branch HEAD.
+		return "", fmt.Errorf("determine current branch: %w", err)
+	}
+	cmd.From = cmp.Or(cmd.From, currentBranch)
+
+	upstack, err := svc.ListUpstack(ctx, cmd.From)
+	if err != nil {
+		return "", fmt.Errorf("list upstack branches: %w", err)
+	}
+
+	var totalCommits int
+	branches := make([]widget.CommitPickBranch, 0, len(upstack))
+	shortToLongHash := make(map[git.Hash]git.Hash)
+	for _, name := range upstack {
+		if name == store.Trunk() {
+			continue
+		}
+
+		// TODO: build commit list for each branch concurrently
+		b, err := svc.LookupBranch(ctx, name)
+		if err != nil {
+			log.Warn("Could not look up branch. Skipping.",
+				"branch", name, "error", err)
+			continue
+		}
+
+		// If doing a --from=$other,
+		// where $other is downstack from current,
+		// we don't want to list commits for current branch,
+		// so add an empty entry for it.
+		if name == currentBranch {
+			// Don't list the current branch's commits.
+			branches = append(branches, widget.CommitPickBranch{
+				Branch: name,
+				Base:   b.Base,
+			})
+			continue
+		}
+
+		commits, err := repo.ListCommitsDetails(ctx,
+			git.CommitRangeFrom(b.Head).
+				ExcludeFrom(b.BaseHash).
+				FirstParent())
+		if err != nil {
+			log.Warn("Could not list commits for branch. Skipping.",
+				"branch", name, "error", err)
+		}
+
+		commitSummaries := make([]widget.CommitSummary, len(commits))
+		for i, c := range commits {
+			commitSummaries[i] = widget.CommitSummary{
+				ShortHash:  c.ShortHash,
+				Subject:    c.Subject,
+				AuthorDate: c.AuthorDate,
+			}
+			shortToLongHash[c.ShortHash] = c.Hash
+		}
+
+		branches = append(branches, widget.CommitPickBranch{
+			Branch:  name,
+			Base:    b.Base,
+			Commits: commitSummaries,
+		})
+		totalCommits += len(commitSummaries)
+	}
+
+	if totalCommits == 0 {
+		log.Warn("Please provide a commit hash to cherry pick from.")
+		return "", fmt.Errorf("upstack of %v does not have any commits to cherry-pick", cmd.From)
+	}
+
+	msg := fmt.Sprintf("Selected commit will be cherry-picked into %v", currentBranch)
+	var selected git.Hash
+	prompt := widget.NewCommitPick().
+		WithTitle("Pick a commit").
+		WithDescription(msg).
+		WithBranches(branches...).
+		WithValue(&selected)
+	if err := ui.Run(view, prompt); err != nil {
+		return "", err
+	}
+
+	if long, ok := shortToLongHash[selected]; ok {
+		// This will always be true but it doesn't hurt
+		// to be defensive here.
+		selected = long
+	}
+	return selected, nil
+}

doc/includes/cli-reference.md

@@ -12,7 +12,7 @@ gs (git-spice) is a command line tool for stacking Git branches.
 * `-C`, `--dir=DIR`: Change to DIR before doing anything
 * `--[no-]prompt`: Whether to prompt for missing information
 
-**Configuration**: [spice.forge.github.url](/cli/config.md#spiceforgegithuburl), [spice.forge.github.apiUrl](/cli/config.md#spiceforgegithubapiurl), [spice.forge.gitlab.url](/cli/config.md#spiceforgegitlaburl), [spice.forge.gitlab.oauth.clientID](/cli/config.md#spiceforgegitlaboauthclientid)
+**Configuration**: [spice.forge.gitlab.url](/cli/config.md#spiceforgegitlaburl), [spice.forge.gitlab.oauth.clientID](/cli/config.md#spiceforgegitlaboauthclientid), [spice.forge.github.url](/cli/config.md#spiceforgegithuburl), [spice.forge.github.apiUrl](/cli/config.md#spiceforgegithubapiurl)
 
 ## Shell
 
@@ -820,6 +820,38 @@ followed by 'gs upstack restack'.
 * `--no-edit`: Don't edit the commit message
 * `--no-verify`: Bypass pre-commit and commit-msg hooks.
 
+### gs commit pick
+
+```
+gs commit (c) pick (p) [<commit>] [flags]
+```
+
+Cherry-pick a commit
+
+Apply the changes introduced by a commit to the current branch
+and restack the upstack branches.
+
+If a commit is not specified, a prompt will allow picking
+from commits of upstack branches of the current branch.
+Use the --from option to pick a commit from a different branch
+or its upstack.
+
+By default, commit messages for cherry-picked commits will be used verbatim.
+Supply --edit to open an editor and change the commit message,
+or set the spice.commitPick.edit configuration option to true
+to always open an editor for cherry picks.
+
+**Arguments**
+
+* `commit`: Commit to cherry-pick
+
+**Flags**
+
+* `--[no-]edit` ([:material-wrench:{ .middle title="spice.commitPick.edit" }](/cli/config.md#spicecommitpickedit)): Whether to open an editor to edit the commit message.
+* `--from=NAME`: Branch whose upstack commits will be considered.
+
+**Configuration**: [spice.commitPick.edit](/cli/config.md#spicecommitpickedit)
+
 ### gs commit split
 
 ```
@@ -863,7 +895,7 @@ and use --edit to override it.
 
 **Flags**
 
-* `--[no-]edit` ([:material-wrench:{ .middle title="spice.rebaseContinue.edit" }](/cli/config.md#spicerebasecontinueedit)): Whehter to open an editor to edit the commit message.
+* `--[no-]edit` ([:material-wrench:{ .middle title="spice.rebaseContinue.edit" }](/cli/config.md#spicerebasecontinueedit)): Whether to open an editor to edit the commit message.
 
 **Configuration**: [spice.rebaseContinue.edit](/cli/config.md#spicerebasecontinueedit)
 

doc/includes/cli-shorthands.md

@@ -14,6 +14,7 @@
 | gs buntr | [gs branch untrack](/cli/reference.md#gs-branch-untrack) |
 | gs ca | [gs commit amend](/cli/reference.md#gs-commit-amend) |
 | gs cc | [gs commit create](/cli/reference.md#gs-commit-create) |
+| gs cp | [gs commit pick](/cli/reference.md#gs-commit-pick) |
 | gs csp | [gs commit split](/cli/reference.md#gs-commit-split) |
 | gs dse | [gs downstack edit](/cli/reference.md#gs-downstack-edit) |
 | gs dss | [gs downstack submit](/cli/reference.md#gs-downstack-submit) |

doc/src/cli/config.md

@@ -54,6 +54,21 @@ and use the `--commit` flag to commit changes when needed.
 - `true` (default)
 - `false`
 
+### spice.commitPick.edit
+
+<!-- gs:version unreleased -->
+
+Whether $$gs commit pick$$ should open an editor to modify commit messages
+of cherry-picked commits before committing them.
+
+If set to true, opt-out with the `--no-edit` flag.
+If set to false, opt-in with the `--edit` flag.
+
+**Accepted values:**
+
+- `true`
+- `false` (default)
+
 ### spice.forge.github.apiUrl
 
 URL at which the GitHub API is available.