Merge pull request 'Add agentpr pr edit subcommand' (#15) from benvin/agentpr-pr-edit into main

Reviewed-on: #15

AGENTS.md

@@ -8,9 +8,9 @@ from Vault, so actions are attributed to the agent rather than to whoever runs
 the tool. Setting `AGENT_LOGIN` selects a different agent identity, so a service
 like repospawner can run these tools as itself.
 
-- **`agentpr`** — create pull requests and post PR comments as `unkin-agent`
-  (fixes the "tea posts as Ben" attribution problem). Subcommands:
-  `pr create`, `pr comment`, `whoami`.
+- **`agentpr`** — create and edit pull requests, and post PR comments, as
+  `unkin-agent` (fixes the "tea posts as Ben" attribution problem).
+  Subcommands: `pr create`, `pr comment`, `pr edit`, `whoami`.
 - **`watchpr`** — poll one or more PRs and exit when a tracked PR changes
   meaningfully: it merges/closes, gets a new non-agent comment, its CI fails,
   or it loses mergeability. Benign transitions (CI pending→success, the agent's
@@ -28,7 +28,7 @@ parsing, watch-state comparison, git worktree helpers).
 ## Structure
 
 ```
-cmd/agentpr/main.go      # agentpr CLI (pr create / pr comment / whoami)
+cmd/agentpr/main.go      # agentpr CLI (pr create / pr comment / pr edit / whoami)
 cmd/watchpr/main.go      # watchpr CLI (poll + meaningful-change exit)
 cmd/agentws/main.go      # agentws CLI (new / list / rm / clean / token / credential)
 cmd/agentws/prune.go     # agentws prune (classify worktrees, remove the safe ones)
@@ -36,7 +36,7 @@ cmd/agentvault/main.go   # agentvault CLI (seed-outpost / seed-oauth)
 internal/agent/          # shared plumbing:
   token.go               #   env config + in-process Gitea-token cache
   vault.go               #   AppRole login + read the gitea creds path
-  gitea.go               #   Gitea REST client (PR create/get, comments, status, whoami)
+  gitea.go               #   Gitea REST client (PR create/edit/get, comments, status, whoami)
   parse.go               #   owner/repo#N and owner/repo parsing
   watch.go               #   PRState snapshot + MeaningfulChange comparison
   git.go                 #   git worktree/clone/fetch helpers (os/exec, no go-git)

README.md

@@ -6,7 +6,8 @@ token from Vault, so automated PRs, comments and pushes are attributed to the
 agent — not to whoever happens to run the command. Set `AGENT_LOGIN` to act as a
 different agent identity.
 
-- **`agentpr`** — create pull requests and post PR comments as the agent user.
+- **`agentpr`** — create and edit pull requests, and post PR comments as the
+  agent user.
 - **`watchpr`** — poll one or more PRs and exit when one changes in a way worth
   acting on.
 - **`agentws`** — manage per-branch git worktrees for `unkin-agent`, cloning
@@ -50,6 +51,11 @@ agentpr pr create --repo unkin/argocd-apps \
 # Comment on a PR
 agentpr pr comment --repo unkin/argocd-apps --pr 42 --body "Rebased, CI green."
 
+# Edit a PR's title and/or body; an omitted flag is left unchanged
+agentpr pr edit --repo unkin/argocd-apps --pr 42 --body "Adds the ServiceAccount ..."
+agentpr pr edit --repo unkin/argocd-apps --pr 42 --title "Add woodpecker SA"
+# prints: #<number> <html_url>
+
 agentpr --version
 agentpr --help
 ```

cmd/agentpr/main.go

@@ -5,6 +5,7 @@
 //
 //	agentpr pr create --repo owner/repo --base main --head feature --title T --body B
 //	agentpr pr comment --repo owner/repo --pr 12 --body "..."
+//	agentpr pr edit --repo owner/repo --pr 12 --title T --body B
 //	agentpr whoami
 package main
 
@@ -56,9 +57,9 @@ func client() (*agent.GiteaClient, error) {
 func newPRCmd() *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "pr",
-		Short: "Create PRs and post PR comments",
+		Short: "Create and edit PRs, and post PR comments",
 	}
-	cmd.AddCommand(newPRCreateCmd(), newPRCommentCmd())
+	cmd.AddCommand(newPRCreateCmd(), newPRCommentCmd(), newPREditCmd())
 	return cmd
 }
 
@@ -143,6 +144,60 @@ func newPRCommentCmd() *cobra.Command {
 	return cmd
 }
 
+func newPREditCmd() *cobra.Command {
+	var repo, title, body string
+	var pr int
+	cmd := &cobra.Command{
+		Use:          "edit",
+		Short:        "Edit a pull request's title and/or body",
+		SilenceUsage: true,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			owner, name, err := agent.ParseRepo(repo)
+			if err != nil {
+				return err
+			}
+			if pr <= 0 {
+				return fmt.Errorf("--pr must be a positive PR number")
+			}
+			// Only the flags actually given are sent: omitting --title must
+			// leave the title as it is, not blank it.
+			var opts agent.EditPROptions
+			if cmd.Flags().Changed("title") {
+				// Gitea ignores an empty title, so sending one would report
+				// success while changing nothing.
+				if title == "" {
+					return fmt.Errorf("--title cannot be empty: a title can be set but not cleared")
+				}
+				opts.Title = &title
+			}
+			if cmd.Flags().Changed("body") {
+				opts.Body = &body
+			}
+			if opts.Title == nil && opts.Body == nil {
+				return fmt.Errorf("at least one of --title or --body is required")
+			}
+			c, err := client()
+			if err != nil {
+				return err
+			}
+			updated, err := c.EditPR(owner+"/"+name, pr, opts)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("#%d %s\n", updated.Number, updated.HTMLURL)
+			return nil
+		},
+	}
+	f := cmd.Flags()
+	f.StringVar(&repo, "repo", "", "Repository as owner/repo (required)")
+	f.IntVar(&pr, "pr", 0, "PR number (required)")
+	f.StringVar(&title, "title", "", "New PR title (unchanged when omitted)")
+	f.StringVar(&body, "body", "", "New PR body (unchanged when omitted)")
+	_ = cmd.MarkFlagRequired("repo")
+	_ = cmd.MarkFlagRequired("pr")
+	return cmd
+}
+
 func newWhoamiCmd() *cobra.Command {
 	return &cobra.Command{
 		Use:          "whoami",

cmd/agentpr/main_test.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"io"
+	"strings"
 	"testing"
 )
 
@@ -16,3 +17,35 @@ func TestExecuteBadRepoErrors(t *testing.T) {
 		t.Fatal("Execute() = nil, want error for a malformed --repo")
 	}
 }
+
+// `pr edit` with neither --title nor --body has nothing to send; it must fail
+// with a usage error before any Vault/Gitea call, so this stays hermetic.
+func TestPREditRequiresTitleOrBody(t *testing.T) {
+	cmd := newRootCmd()
+	cmd.SetArgs([]string{"pr", "edit", "--repo", "unkin/repo", "--pr", "7"})
+	cmd.SetOut(io.Discard)
+	cmd.SetErr(io.Discard)
+	err := cmd.Execute()
+	if err == nil {
+		t.Fatal("Execute() = nil, want an error when neither --title nor --body is given")
+	}
+	if !strings.Contains(err.Error(), "--title or --body") {
+		t.Errorf("error = %q, want it to name the missing flags", err)
+	}
+}
+
+// Gitea silently ignores an empty title, so `pr edit --title ""` would report
+// success while changing nothing; it must fail before any Vault/Gitea call.
+func TestPREditRejectsEmptyTitle(t *testing.T) {
+	cmd := newRootCmd()
+	cmd.SetArgs([]string{"pr", "edit", "--repo", "unkin/repo", "--pr", "7", "--title", ""})
+	cmd.SetOut(io.Discard)
+	cmd.SetErr(io.Discard)
+	err := cmd.Execute()
+	if err == nil {
+		t.Fatal("Execute() = nil, want an error for an empty --title")
+	}
+	if !strings.Contains(err.Error(), "--title cannot be empty") {
+		t.Errorf("error = %q, want it to reject the empty title", err)
+	}
+}

internal/agent/client_test.go

@@ -98,6 +98,80 @@ func TestCreatePRRequestBody(t *testing.T) {
 	}
 }
 
+// An edit must send only the fields it was given: Gitea overwrites whatever
+// key it receives, so an omitted --title arriving as "" would blank the title.
+func TestEditPRSendsOnlySuppliedFields(t *testing.T) {
+	title, body, empty := "new title", "new body", ""
+	tests := []struct {
+		name string
+		opts EditPROptions
+		want map[string]any
+	}{
+		{"body only", EditPROptions{Body: &body}, map[string]any{"body": "new body"}},
+		{"title only", EditPROptions{Title: &title}, map[string]any{"title": "new title"}},
+		{"both", EditPROptions{Title: &title, Body: &body}, map[string]any{"title": "new title", "body": "new body"}},
+		{"explicit empty body is sent", EditPROptions{Body: &empty}, map[string]any{"body": ""}},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var gotBody map[string]any
+			var gotMethod, gotPath string
+			mux := http.NewServeMux()
+			mux.HandleFunc("/api/v1/repos/unkin/repo/pulls/7", func(w http.ResponseWriter, r *http.Request) {
+				gotMethod, gotPath = r.Method, r.URL.Path
+				_ = json.NewDecoder(r.Body).Decode(&gotBody)
+				_, _ = io.WriteString(w, `{"number":7,"title":"new title","html_url":"https://git.unkin.net/unkin/repo/pulls/7"}`)
+			})
+			srv := httptest.NewServer(mux)
+			defer srv.Close()
+
+			c := &GiteaClient{BaseURL: srv.URL, Token: "gitea-abc", HTTP: srv.Client()}
+			pr, err := c.EditPR("unkin/repo", 7, tt.opts)
+			if err != nil {
+				t.Fatalf("EditPR: %v", err)
+			}
+			if gotMethod != http.MethodPatch {
+				t.Errorf("method = %s, want PATCH", gotMethod)
+			}
+			if gotPath != "/api/v1/repos/unkin/repo/pulls/7" {
+				t.Errorf("path = %q", gotPath)
+			}
+			if len(gotBody) != len(tt.want) {
+				t.Errorf("payload = %v, want exactly the supplied fields %v", gotBody, tt.want)
+			}
+			for k, v := range tt.want {
+				if gotBody[k] != v {
+					t.Errorf("payload[%q] = %v, want %v", k, gotBody[k], v)
+				}
+			}
+			if pr.Number != 7 || pr.HTMLURL == "" {
+				t.Errorf("parsed PR = %+v", pr)
+			}
+		})
+	}
+}
+
+// A non-2xx must surface the API's own message rather than a bare status.
+func TestEditPRAPIError(t *testing.T) {
+	mux := http.NewServeMux()
+	mux.HandleFunc("/api/v1/repos/unkin/repo/pulls/7", func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusNotFound)
+		_, _ = io.WriteString(w, `{"message":"not found","url":"https://git.unkin.net/api/swagger","errors":null}`)
+	})
+	srv := httptest.NewServer(mux)
+	defer srv.Close()
+
+	title := "new title"
+	c := &GiteaClient{BaseURL: srv.URL, Token: "t", HTTP: srv.Client()}
+	_, err := c.EditPR("unkin/repo", 7, EditPROptions{Title: &title})
+	if err == nil {
+		t.Fatal("expected error on 404")
+	}
+	if !strings.Contains(err.Error(), `"message":"not found"`) {
+		t.Errorf("error %q should carry the API message", err)
+	}
+}
+
 func TestCreateComment(t *testing.T) {
 	var gotBody map[string]string
 	mux := http.NewServeMux()

internal/agent/gitea.go

@@ -214,6 +214,24 @@ func (c *GiteaClient) CreatePR(repoPath string, opts CreatePROptions) (PullReque
 	return pr, err
 }
 
+// EditPROptions are the fields an edit may change. Pointers so an unset field
+// is omitted from the payload entirely, leaving that field as it is. The two
+// fields are not symmetric: Gitea only applies a title when it is non-empty,
+// so Title can be set but never cleared and a "" title is a silent no-op,
+// while a pointer to "" Body really does blank the body.
+type EditPROptions struct {
+	Title *string `json:"title,omitempty"`
+	Body  *string `json:"body,omitempty"`
+}
+
+// EditPR updates a pull request's title and/or body
+// (PATCH /api/v1/repos/{owner}/{repo}/pulls/{index}).
+func (c *GiteaClient) EditPR(repoPath string, number int, opts EditPROptions) (PullRequest, error) {
+	var pr PullRequest
+	err := c.do(http.MethodPatch, fmt.Sprintf("/api/v1/repos/%s/pulls/%d", repoPath, number), opts, &pr)
+	return pr, err
+}
+
 // GetPR fetches a single pull request.
 func (c *GiteaClient) GetPR(repoPath string, number int) (PullRequest, error) {
 	var pr PullRequest