Add background audits of the default branch's newest commit

internal/agents/workflows.go

@@ -231,7 +231,7 @@ type parentStage struct {
 	commit string
 }
 
-func (m *Manager) StartWorkflow(ctx context.Context, project api.Project, creator api.User, title, base, actor, name, brief string, todoItem *string) ([]api.Task, error) {
+func (m *Manager) StartWorkflow(ctx context.Context, project api.Project, creator api.User, title, base, actor, name, brief string, todoItem *string, audit string) ([]api.Task, error) {
 	if creator.GitName == "" || creator.GitEmail == "" {
 		return nil, ErrNoGitIdentity
 	}
@@ -241,6 +241,7 @@ func (m *Manager) StartWorkflow(ctx context.Context, project api.Project, creato
 	}
 	frozen.Brief = brief
 	frozen.Title = title
+	frozen.Audit = audit
 
 	run := store.NewID()
 	tasks := []api.Task{}
@@ -250,23 +251,29 @@ func (m *Manager) StartWorkflow(ctx context.Context, project api.Project, creato
 			from = project.DefaultBranch
 		}
 		task, err := m.startStage(ctx, project, creator, frozen, run, stage, from, todoItem, nil, actor)
+		if task.Id != "" {
+			tasks = append(tasks, task)
+		}
 		if err != nil {
 			return tasks, fmt.Errorf("workflow %q: stage %q did not start: %w", name, stage, err)
 		}
-		tasks = append(tasks, task)
 	}
 	return tasks, nil
 }
 
 func (m *Manager) startStage(ctx context.Context, project api.Project, creator api.User, frozen store.FrozenWorkflow, run, stage, base string, todoItem *string, parents []parentStage, actor string) (api.Task, error) {
-	task, err := m.createTask(ctx, project, api.Task{
+	t := api.Task{
 		Title:         fmt.Sprintf("%s: %s", frozen.Title, stage),
 		MergeTitle:    frozen.Title,
 		CreatedBy:     creator.Login,
 		TodoItem:      todoItem,
 		WorkflowRun:   &run,
 		WorkflowStage: &stage,
-	}, &frozen, base, actor)
+	}
+	if frozen.Audit != "" {
+		t.Audit = &frozen.Audit
+	}
+	task, err := m.createTask(ctx, project, t, &frozen, base, actor)
 	if err != nil {
 		return api.Task{}, err
 	}
@@ -489,7 +496,11 @@ func (m *Manager) advanceTo(ctx context.Context, from api.Task, frozen store.Fro
 	}
 
 	base := parents[0].commit
-	if workflow.FromMain(frozen.Definition, stage) {
+	switch {
+	case !workflow.FromMain(frozen.Definition, stage):
+	case frozen.Audit != "":
+		base = frozen.Audit
+	default:
 		base = project.DefaultBranch
 	}
 	task, err := m.startStage(ctx, project, creator, frozen, *from.WorkflowRun, stage, base, from.TodoItem, parents, "byre")
@@ -811,6 +822,32 @@ func (m *Manager) workflowTools(tool func(name, description, schema string, run
 				return fmt.Sprintf("Project %s reviews with workflow %q from its next snapshot on.", p.Name, p.ReviewWorkflow), nil
 			}),
 
+		tool("set_audit_workflow",
+			"Set the audit workflow (any saved workflow) that byre runs in the background on a project's default branch: one run at a time, started whenever the branch's newest commit hasn't had one, to check the whole codebase against its standards rather than one change. "+
+				"An audit's tasks stay out of list_tasks and your signals until one asks a question, calls ready_for_merge or hits an error; one that suggests discarding first is discarded by byre. An empty workflow turns audits off. Only when the human asks.",
+			`{"type": "object", "properties": {
+				"project_id": {"type": "string"},
+				"workflow": {"type": "string"}
+			}, "required": ["project_id", "workflow"]}`,
+			func(ctx context.Context, user api.User, raw json.RawMessage) (string, error) {
+				args := struct {
+					ProjectID string `json:"project_id"`
+					Workflow  string `json:"workflow"`
+				}{}
+				err := json.Unmarshal(raw, &args)
+				if err != nil {
+					return "", err
+				}
+				p, err := m.SetAuditWorkflow(ctx, args.ProjectID, args.Workflow, leadActor(user.Login))
+				if err != nil {
+					return "", err
+				}
+				if p.AuditWorkflow == "" {
+					return fmt.Sprintf("Project %s has no audit workflow now: it isn't audited.", p.Name), nil
+				}
+				return fmt.Sprintf("Project %s is audited with workflow %q.", p.Name, p.AuditWorkflow), nil
+			}),
+
 		tool("delete_workflow",
 			"Delete a workflow from the server. Tasks that froze it keep their copy. Only when the human asks.",
 			`{"type": "object", "properties": {"name": {"type": "string"}}, "required": ["name"]}`,