feat(stack reorder): Generate plan for stack (#157)

Getting pretty close to having an MVP on this feature.

The generated plan in the test case looks like
```
    plan_test.go:57: stack-branch one --trunk main@a50ac627fb10b6a7e19d39fde5f925ff9d2e9c29
    plan_test.go:57: pick 51f48a6  # Write file
    plan_test.go:57: pick baf3979  # Write file
    plan_test.go:57: stack-branch two --parent one
    plan_test.go:57: pick d856653  # Write fichier
    plan_test.go:57: pick 28fbcea  # Write fichier
```

The test cases for plan are a bit brittle at the moment, but I think we're still in the stage of figuring it out such that I think that's fine for now.

.pre-commit-config.yaml

@@ -12,7 +12,7 @@ repos:
         files: ".+$"
         language: system
         entry: |
-          sh -c 'go run golang.org/x/tools/cmd/goimports@latest .'
+          sh -c 'go run golang.org/x/tools/cmd/goimports@latest -w .'
 
   - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v4.4.0

cmd/av/commit_amend.go

@@ -74,10 +74,7 @@ var commitAmendCmd = &cobra.Command{
 			return err
 		}
 
-		branchesToSync, err := meta.SubsequentBranches(tx, currentBranchName)
-		if err != nil {
-			return err
-		}
+		branchesToSync := meta.SubsequentBranches(tx, currentBranchName)
 
 		err = actions.SyncStack(ctx, repo, client, tx, branchesToSync, state)
 		if err != nil {

cmd/av/commit_create.go

@@ -93,10 +93,7 @@ func commitCreate(repo *git.Repo, currentBranchName string, flags struct {
 		return err
 	}
 
-	branchesToSync, err := meta.SubsequentBranches(tx, currentBranchName)
-	if err != nil {
-		return err
-	}
+	branchesToSync := meta.SubsequentBranches(tx, currentBranchName)
 
 	err = actions.SyncStack(ctx, repo, client, tx, branchesToSync, state)
 	if err != nil {

cmd/av/stack_next.go

@@ -37,10 +37,7 @@ var stackNextCmd = &cobra.Command{
 		if err != nil {
 			return err
 		}
-		subsequentBranches, err := meta.SubsequentBranches(tx, currentBranch)
-		if err != nil {
-			return err
-		}
+		subsequentBranches := meta.SubsequentBranches(tx, currentBranch)
 
 		var branchToCheckout string
 		if stackNextFlags.Last {

cmd/av/stack_submit.go

@@ -40,10 +40,7 @@ var stackSubmitCmd = &cobra.Command{
 		if err != nil {
 			return err
 		}
-		subsequentBranches, err := meta.SubsequentBranches(tx, currentBranch)
-		if err != nil {
-			return err
-		}
+		subsequentBranches := meta.SubsequentBranches(tx, currentBranch)
 		var branchesToSubmit []string
 		branchesToSubmit = append(branchesToSubmit, previousBranches...)
 		branchesToSubmit = append(branchesToSubmit, currentBranch)

cmd/av/stack_sync.go

@@ -220,10 +220,7 @@ base branch.
 					continue
 				}
 				branchesToSync = append(branchesToSync, br.Name)
-				nextBranches, err := meta.SubsequentBranches(tx, branchesToSync[len(branchesToSync)-1])
-				if err != nil {
-					return err
-				}
+				nextBranches := meta.SubsequentBranches(tx, branchesToSync[len(branchesToSync)-1])
 				branchesToSync = append(branchesToSync, nextBranches...)
 			}
 			state.Branches = branchesToSync
@@ -237,10 +234,7 @@ base branch.
 				return err
 			}
 			branchesToSync = append(branchesToSync, currentBranch)
-			nextBranches, err := meta.SubsequentBranches(tx, branchesToSync[len(branchesToSync)-1])
-			if err != nil {
-				return err
-			}
+			nextBranches := meta.SubsequentBranches(tx, branchesToSync[len(branchesToSync)-1])
 			branchesToSync = append(branchesToSync, nextBranches...)
 			state.Branches = branchesToSync
 		}

go.mod

@@ -12,6 +12,7 @@ require (
 	github.com/kr/text v0.2.0
 	github.com/segmentio/golines v0.11.0
 	github.com/shurcooL/githubv4 v0.0.0-20220115235240-a14260e6f8a2
+	github.com/shurcooL/graphql v0.0.0-20220606043923-3cf50f8a0a29
 	github.com/sirupsen/logrus v1.9.0
 	github.com/spf13/cobra v1.7.0
 	github.com/spf13/pflag v1.0.5
@@ -151,7 +152,6 @@ require (
 	github.com/sashamelentyev/usestdlibvars v1.23.0 // indirect
 	github.com/securego/gosec/v2 v2.15.0 // indirect
 	github.com/shazow/go-diff v0.0.0-20160112020656-b6b7b6733b8c // indirect
-	github.com/shurcooL/graphql v0.0.0-20220606043923-3cf50f8a0a29 // indirect
 	github.com/sivchari/containedctx v1.0.3 // indirect
 	github.com/sivchari/nosnakecase v1.7.0 // indirect
 	github.com/sivchari/tenv v1.7.1 // indirect

go.sum

@@ -486,8 +486,6 @@ github.com/shurcooL/githubv4 v0.0.0-20220115235240-a14260e6f8a2 h1:82EIpiGB79OIP
 github.com/shurcooL/githubv4 v0.0.0-20220115235240-a14260e6f8a2/go.mod h1:hAF0iLZy4td2EX+/8Tw+4nodhlMrwN3HupfaXj3zkGo=
 github.com/shurcooL/go v0.0.0-20180423040247-9e1955d9fb6e/go.mod h1:TDJrrUr11Vxrven61rcy3hJMUqaf/CLWYhHNPmT14Lk=
 github.com/shurcooL/go-goon v0.0.0-20170922171312-37c2f522c041/go.mod h1:N5mDOmsrJOB+vfqUK+7DmDyjhSLIIBnXo9lvZJj3MWQ=
-github.com/shurcooL/graphql v0.0.0-20200928012149-18c5c3165e3a h1:KikTa6HtAK8cS1qjvUvvq4QO21QnwC+EfvB+OAuZ/ZU=
-github.com/shurcooL/graphql v0.0.0-20200928012149-18c5c3165e3a/go.mod h1:AuYgA5Kyo4c7HfUmvRGs/6rGlMMV/6B1bVnB9JxJEEg=
 github.com/shurcooL/graphql v0.0.0-20220606043923-3cf50f8a0a29 h1:B1PEwpArrNp4dkQrfxh/abbBAOZBVp0ds+fBEOUOqOc=
 github.com/shurcooL/graphql v0.0.0-20220606043923-3cf50f8a0a29/go.mod h1:AuYgA5Kyo4c7HfUmvRGs/6rGlMMV/6B1bVnB9JxJEEg=
 github.com/sirupsen/logrus v1.2.0/go.mod h1:LxeOpSwHxABJmUn/MG1IvRgCAasNZTLOkJPxbbu5VWo=
@@ -698,8 +696,6 @@ golang.org/x/net v0.2.0/go.mod h1:KqCZLdyyvdV855qA2rE3GC2aiw5xGR5TEjj8smXukLY=
 golang.org/x/net v0.3.0/go.mod h1:MBQ8lrhLObU/6UmLb4fmbmk5OcyYmqtbGd/9yIeKjEE=
 golang.org/x/net v0.5.0/go.mod h1:DivGGAXEgPSlEBzxGzZI+ZLohi+xUj054jfeKui00ws=
 golang.org/x/net v0.6.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
-golang.org/x/net v0.9.0 h1:aWJ/m6xSmxWBx+V0XRHTlrYrPG56jKsLdTFmsSsCzOM=
-golang.org/x/net v0.9.0/go.mod h1:d48xBJpPfHeWQsugry2m+kC02ZBRGRgulfHnEXEuWns=
 golang.org/x/net v0.10.0 h1:X2//UzNDwYmtCLn7To6G58Wr6f5ahEAQgKNzv9Y951M=
 golang.org/x/net v0.10.0/go.mod h1:0qNGK6F8kojg2nk9dLZ2mShWaEBan6FAoqfSigmmuDg=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
@@ -788,8 +784,6 @@ golang.org/x/sys v0.3.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.4.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.7.0 h1:3jlCCIQZPdOYu1h8BkNvLz8Kgwtae2cagcG/VamtZRU=
-golang.org/x/sys v0.7.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.8.0 h1:EBmGv8NaZBZTWvrbjNoL6HVt+IVy3QDQpJs7VRIw3tU=
 golang.org/x/sys v0.8.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
@@ -799,8 +793,6 @@ golang.org/x/term v0.2.0/go.mod h1:TVmDHMZPmdnySmBfhjOoOdhjzdE1h4u1VwSiw2l1Nuc=
 golang.org/x/term v0.3.0/go.mod h1:q750SLmJuPmVoN1blW3UFBPREJfb1KmY3vwxfr+nFDA=
 golang.org/x/term v0.4.0/go.mod h1:9P2UbLfCdcvo3p/nzKvsmas4TnlujnuoV9hGgYzW1lQ=
 golang.org/x/term v0.5.0/go.mod h1:jMB1sMXY+tzblOD4FWmEbocvup2/aLOaQEp7JmGp78k=
-golang.org/x/term v0.7.0 h1:BEvjmm5fURWqcfbSKTdpkDXYBrUS1c0m8agp14W48vQ=
-golang.org/x/term v0.7.0/go.mod h1:P32HKFT3hSsZrRxla30E9HqToFYAQPCMs/zFMBUFqPY=
 golang.org/x/term v0.8.0 h1:n5xxQn2i3PC0yLAbjTpNT85q/Kgzcr2gIoX9OrJUols=
 golang.org/x/term v0.8.0/go.mod h1:xPskH00ivmX89bAKVGSKKtLOWNx2+17Eiy94tnKShWo=
 golang.org/x/text v0.0.0-20170915032832-14c0d48ead0c/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

internal/git/catfile.go

@@ -1,9 +1,13 @@
 package git
 
 import (
+	"bufio"
 	"bytes"
 	"fmt"
 	"io"
+	"strings"
+
+	"github.com/sirupsen/logrus"
 
 	"emperror.dev/errors"
 )
@@ -17,7 +21,7 @@ type GetRefsItem struct {
 	// The revision that was requested (exactly as given in GetRefs.Revisions)
 	Revision string
 	// The git object ID that the revision resolved to
-	Oid string
+	OID string
 	// The type of the git object
 	Type string
 	// The contents of the git object
@@ -33,11 +37,15 @@ func (r *Repo) GetRefs(opts *GetRefs) ([]*GetRefsItem, error) {
 		input.WriteString("\n")
 	}
 
-	res, err := r.GitStdin([]string{"cat-file", "--batch"}, input)
+	res, err := r.Run(&RunOpts{
+		Args:      []string{"cat-file", "--batch"},
+		Stdin:     input,
+		ExitError: true,
+	})
 	if err != nil {
 		return nil, err
 	}
-	output := bytes.NewBufferString(res)
+	output := bytes.NewBuffer(res.Stdout)
 	items := make([]*GetRefsItem, 0, len(opts.Revisions))
 	for _, rev := range opts.Revisions {
 		// The output *usually* looks like:
@@ -48,9 +56,9 @@ func (r *Repo) GetRefs(opts *GetRefs) ([]*GetRefsItem, error) {
 
 		item := GetRefsItem{Revision: rev}
 		items = append(items, &item)
-		_, err := fmt.Fscanf(output, "%s %s", &item.Oid, &item.Type)
+		_, err := fmt.Fscanf(output, "%s %s", &item.OID, &item.Type)
 		if err != nil {
-			return nil, errors.Wrap(err, "failed to read cat-file output")
+			return nil, errors.WrapIff(err, "failed to read cat-file output for revision %q", rev)
 		}
 
 		// special case where the rest of the format is ignored
@@ -69,9 +77,14 @@ func (r *Repo) GetRefs(opts *GetRefs) ([]*GetRefsItem, error) {
 			return nil, errors.Wrap(err, "failed to read cat-file output")
 		}
 		item.Contents = make([]byte, size)
-		_, err = io.ReadFull(output, item.Contents)
-		if err != nil {
-			return nil, errors.Wrap(err, "failed to read cat-file output")
+		if n, err := io.ReadFull(output, item.Contents); err != nil {
+			logrus.WithFields(logrus.Fields{
+				logrus.ErrorKey: err,
+				"revision":      rev,
+				"size":          size,
+				"read":          n,
+			}).Debug("failed to read contents from cat-file output")
+			return nil, errors.WrapIff(err, "failed to read cat-file output for revision %q", rev)
 		}
 
 		// output includes a newline after the item contents
@@ -91,3 +104,74 @@ func (r *Repo) GetRefs(opts *GetRefs) ([]*GetRefsItem, error) {
 
 	return items, nil
 }
+
+type Commit struct {
+	Tree      string
+	Parents   []string
+	Author    string
+	Committer string
+	Message   string
+}
+
+func (c *Commit) MessageTitle() string {
+	if i := strings.Index(c.Message, "\n"); i >= 0 {
+		return c.Message[:i]
+	}
+	return c.Message
+}
+
+func ParseCommitContents(contents []byte) (Commit, error) {
+	// read line by line
+	s := bufio.NewReader(bytes.NewReader(contents))
+	var commit Commit
+	for {
+		line, err := s.ReadString('\n')
+		if errors.Is(err, io.EOF) {
+			break
+		} else if err != nil {
+			return commit, err
+		}
+
+		if line == "\n" {
+			// Blank line indicates the end of the header and the start of the
+			// commit body.
+			break
+		}
+
+		meta, value, ok := strings.Cut(line, " ")
+		if !ok {
+			return commit, errors.New("invalid commit format")
+		}
+		switch meta {
+		case "tree":
+			commit.Tree = value
+		case "parent":
+			commit.Parents = append(commit.Parents, value)
+		case "author":
+			commit.Author = value
+		case "committer":
+			commit.Committer = value
+		default:
+			// pass
+		}
+	}
+	if commit.Tree == "" {
+		return commit, errors.New("invalid commit format: missing tree")
+	}
+	if commit.Author == "" {
+		return commit, errors.New("invalid commit format: missing author")
+	}
+	if commit.Committer == "" {
+		return commit, errors.New("invalid commit format: missing committer")
+	}
+
+	// The rest of the commit contents is the commit message.
+	// We don't need to parse it, so just read it as-is.
+	message, err := io.ReadAll(s)
+	if err != nil {
+		return commit, err
+	}
+	commit.Message = string(message)
+
+	return commit, nil
+}

internal/git/git.go

@@ -97,6 +97,8 @@ type RunOpts struct {
 	// If true, the standard I/Os are connected to the console, allowing the git command to
 	// interact with the user. Stdout and Stderr will be empty.
 	Interactive bool
+	// The standard input to the command (if any). Mutually exclusive with Interactive.
+	Stdin io.Reader
 }
 
 type Output struct {
@@ -123,6 +125,9 @@ func (r *Repo) Run(opts *RunOpts) (*Output, error) {
 		cmd.Stdout = &stdout
 		cmd.Stderr = &stderr
 	}
+	if opts.Stdin != nil {
+		cmd.Stdin = opts.Stdin
+	}
 	cmd.Env = append(os.Environ(), opts.Env...)
 	err := cmd.Run()
 	var exitError *exec.ExitError
@@ -139,26 +144,6 @@ func (r *Repo) Run(opts *RunOpts) (*Output, error) {
 	}, nil
 }
 
-func (r *Repo) GitStdin(args []string, stdin io.Reader) (string, error) {
-	cmd := exec.Command("git", args...)
-	cmd.Dir = r.repoDir
-	cmd.Stdin = stdin
-	r.log.Debugf("git %s", args)
-	out, err := cmd.Output()
-	if err != nil {
-		stderr := "<no output>"
-		var exitError *exec.ExitError
-		if errors.As(err, &exitError) {
-			stderr = string(exitError.Stderr)
-		}
-		r.log.Errorf("git %s failed: %s: %s", args, err, stderr)
-		return "", errors.Wrapf(err, "git %s", args[0])
-	}
-
-	// trim trailing newline
-	return strings.TrimSpace(string(out)), nil
-}
-
 // DetachedHead returns true if the repository is in the detached HEAD.
 func (r *Repo) DetachedHead() (bool, error) {
 	ret, err := r.Run(&RunOpts{

internal/meta/branch.go

@@ -116,19 +116,17 @@ func PreviousBranches(tx ReadTx, name string) ([]string, error) {
 
 // SubsequentBranches finds all the child branches of the given branch name in
 // "dependency order" (i.e., A comes before B if A is an ancestor of B).
-func SubsequentBranches(tx ReadTx, name string) ([]string, error) {
+// If the tree is not a straight line (which isn't explicitly supported!), the
+// branches will be returned in depth-first traversal order.
+func SubsequentBranches(tx ReadTx, name string) []string {
 	logrus.Debugf("finding subsequent branches for %q", name)
 	var res []string
 	children := Children(tx, name)
 	for _, child := range children {
 		res = append(res, child.Name)
-		desc, err := SubsequentBranches(tx, child.Name)
-		if err != nil {
-			return nil, err
-		}
-		res = append(res, desc...)
+		res = append(res, SubsequentBranches(tx, child.Name)...)
 	}
-	return res, nil
+	return res
 }
 
 // Trunk determines the trunk of a branch.

internal/reorder/cmds_test.go

@@ -13,9 +13,9 @@ func TestState(t *testing.T) {
 		Head:   "owouwu",
 		Commands: []Cmd{
 			StackBranchCmd{Name: "one", Trunk: "main"},
-			PickCmd{"abcd"},
+			PickCmd{"abcd", ""},
 			StackBranchCmd{Name: "two", Parent: "one"},
-			PickCmd{"efgh"},
+			PickCmd{"efgh", ""},
 		},
 	}
 

internal/reorder/pick.go

@@ -1,7 +1,6 @@
 package reorder
 
 import (
-	"fmt"
 	"strings"
 
 	"github.com/aviator-co/av/internal/git"
@@ -13,7 +12,8 @@ import (
 // PickCmd is a command that picks a commit from the history and applies it on
 // top of the current HEAD.
 type PickCmd struct {
-	Commit string
+	Commit  string
+	Comment string
 }
 
 func (p PickCmd) Execute(ctx *Context) error {
@@ -48,7 +48,14 @@ func (p PickCmd) Execute(ctx *Context) error {
 }
 
 func (p PickCmd) String() string {
-	return fmt.Sprintf("pick %s", p.Commit)
+	sb := strings.Builder{}
+	sb.WriteString("pick ")
+	sb.WriteString(p.Commit)
+	if p.Comment != "" {
+		sb.WriteString("  # ")
+		sb.WriteString(p.Comment)
+	}
+	return sb.String()
 }
 
 var _ Cmd = &PickCmd{}