feat(session): support multiple PRs per session

backend/internal/adapters/scm/github/observer_provider.go

@@ -57,36 +57,36 @@ func (p *Provider) RepoPRListGuard(ctx context.Context, repo ports.SCMRepo, etag
 	return ports.SCMGuardResult{ETag: firstNonEmptyHeader(resp.ETag, etag), NotModified: resp.NotModified}, nil
 }
 
-// DetectPRByBranch finds an open PR whose head branch matches the session branch.
-func (p *Provider) DetectPRByBranch(ctx context.Context, repo ports.SCMRepo, branch string) (ports.SCMPRObservation, error) {
-	branch = strings.TrimSpace(branch)
-	if branch == "" {
-		return ports.SCMPRObservation{}, fmt.Errorf("%w: empty branch", ErrNotFound)
-	}
-	pulls, err := p.detectPRByHead(ctx, repo, repo.Owner+":"+branch)
-	if err != nil {
-		return ports.SCMPRObservation{}, err
-	}
-	if len(pulls) == 0 {
-		return ports.SCMPRObservation{}, fmt.Errorf("%w: no open PR for branch %s", ErrNotFound, branch)
-	}
-	return restListPullToSCM(pulls[0]), nil
-}
-
-func (p *Provider) detectPRByHead(ctx context.Context, repo ports.SCMRepo, head string) ([]restListPull, error) {
-	q := url.Values{}
-	q.Set("state", "open")
-	q.Set("head", head)
-	q.Set("per_page", "10")
-	resp, err := p.client.doREST(ctx, http.MethodGet, repoPath(repo.Owner, repo.Name, "pulls"), q, nil)
-	if err != nil {
-		return nil, err
-	}
-	var pulls []restListPull
-	if err := json.Unmarshal(resp.Body, &pulls); err != nil {
-		return nil, fmt.Errorf("github scm: decode branch PR list: %w", err)
+// ListOpenPRsByRepo lists every open pull request in the repository so the
+// observer can attribute each to a session by head-branch prefix. It paginates
+// the REST pulls endpoint; AO repos are not expected to carry thousands of
+// concurrent open PRs, and the observer only calls this when the repo PR-list
+// ETag guard reports a change.
+func (p *Provider) ListOpenPRsByRepo(ctx context.Context, repo ports.SCMRepo) ([]ports.SCMPRObservation, error) {
+	const perPage = 100
+	out := []ports.SCMPRObservation{}
+	for page := 1; ; page++ {
+		q := url.Values{}
+		q.Set("state", "open")
+		q.Set("sort", "updated")
+		q.Set("direction", "desc")
+		q.Set("per_page", strconv.Itoa(perPage))
+		q.Set("page", strconv.Itoa(page))
+		resp, err := p.client.doREST(ctx, http.MethodGet, repoPath(repo.Owner, repo.Name, "pulls"), q, nil)
+		if err != nil {
+			return nil, err
+		}
+		var pulls []restListPull
+		if err := json.Unmarshal(resp.Body, &pulls); err != nil {
+			return nil, fmt.Errorf("github scm: decode open PR list: %w", err)
+		}
+		for _, pull := range pulls {
+			out = append(out, restListPullToSCM(pull))
+		}
+		if len(pulls) < perPage {
+			return out, nil
+		}
 	}
-	return pulls, nil
 }
 
 // CommitChecksGuard checks GitHub's per-commit check-runs ETag guard.

backend/internal/domain/pr.go

@@ -16,6 +16,8 @@ type PRFacts struct {
 	Review         ReviewDecision
 	Mergeability   Mergeability
 	ReviewComments bool // has unresolved review comments (any author) to address
+	SourceBranch   string
+	TargetBranch   string
 	UpdatedAt      time.Time
 }
 

backend/internal/domain/session.go

@@ -61,4 +61,8 @@ type Session struct {
 	SessionRecord
 	Status           SessionStatus `json:"status"`
 	TerminalHandleID string        `json:"terminalHandleId,omitempty"`
+	// PRs are the session's attributed pull requests (one session can own many).
+	// They feed status derivation and are surfaced on the API read model. Not
+	// serialized here: the HTTP boundary maps them to the curated wire shape.
+	PRs []PRFacts `json:"-"`
 }

backend/internal/httpd/apispec/openapi.yaml

@@ -1136,6 +1136,49 @@ components:
       - sessionId
       - reason
       type: object
+    ControllersSessionView:
+      properties:
+        activity:
+          $ref: '#/components/schemas/DomainActivity'
+        createdAt:
+          format: date-time
+          type: string
+        displayName:
+          type: string
+        harness:
+          type: string
+        id:
+          type: string
+        isTerminated:
+          type: boolean
+        issueId:
+          type: string
+        kind:
+          type: string
+        projectId:
+          type: string
+        prs:
+          items:
+            $ref: '#/components/schemas/SessionPRFacts'
+          type: array
+        status:
+          type: string
+        terminalHandleId:
+          type: string
+        updatedAt:
+          format: date-time
+          type: string
+      required:
+      - id
+      - projectId
+      - kind
+      - activity
+      - isTerminated
+      - createdAt
+      - updatedAt
+      - status
+      - prs
+      type: object
     DegradedProject:
       properties:
         id:
@@ -1220,7 +1263,7 @@ components:
       properties:
         sessions:
           items:
-            $ref: '#/components/schemas/Session'
+            $ref: '#/components/schemas/ControllersSessionView'
           type: array
       required:
       - sessions
@@ -1397,7 +1440,7 @@ components:
         ok:
           type: boolean
         session:
-          $ref: '#/components/schemas/Session'
+          $ref: '#/components/schemas/ControllersSessionView'
         sessionId:
           type: string
       required:
@@ -1496,44 +1539,6 @@ components:
       - sessionId
       - message
       type: object
-    Session:
-      properties:
-        activity:
-          $ref: '#/components/schemas/DomainActivity'
-        createdAt:
-          format: date-time
-          type: string
-        displayName:
-          type: string
-        harness:
-          type: string
-        id:
-          type: string
-        isTerminated:
-          type: boolean
-        issueId:
-          type: string
-        kind:
-          type: string
-        projectId:
-          type: string
-        status:
-          type: string
-        terminalHandleId:
-          type: string
-        updatedAt:
-          format: date-time
-          type: string
-      required:
-      - id
-      - projectId
-      - kind
-      - activity
-      - isTerminated
-      - createdAt
-      - updatedAt
-      - status
-      type: object
     SessionPRFacts:
       properties:
         ci:
@@ -1571,7 +1576,7 @@ components:
     SessionResponse:
       properties:
         session:
-          $ref: '#/components/schemas/Session'
+          $ref: '#/components/schemas/ControllersSessionView'
       required:
       - session
       type: object

backend/internal/httpd/controllers/dto.go

@@ -111,9 +111,18 @@ type CleanupSessionsQuery struct {
 	Project string `query:"project,omitempty" description:"Project id filter. When omitted, clean terminated sessions across all projects."`
 }
 
+// SessionView is the session wire shape: the domain read model plus the
+// session's attributed pull requests in the curated SessionPRFacts shape. One
+// session can own many PRs (e.g. a stack), so prs is a list. The embedded
+// domain.Session.PRs field is json:"-"; this curated prs is what serializes.
+type SessionView struct {
+	domain.Session
+	PRs []SessionPRFacts `json:"prs"`
+}
+
 // ListSessionsResponse is the body of GET /api/v1/sessions.
 type ListSessionsResponse struct {
-	Sessions []domain.Session `json:"sessions"`
+	Sessions []SessionView `json:"sessions"`
 }
 
 // SpawnSessionRequest is the body of POST /api/v1/sessions.
@@ -128,7 +137,7 @@ type SpawnSessionRequest struct {
 
 // SessionResponse is the { session } body shared by session create/get.
 type SessionResponse struct {
-	Session domain.Session `json:"session"`
+	Session SessionView `json:"session"`
 }
 
 // RenameSessionRequest is the body of PATCH /api/v1/sessions/{sessionId}.
@@ -147,7 +156,7 @@ type RenameSessionResponse struct {
 type RestoreSessionResponse struct {
 	OK        bool             `json:"ok"`
 	SessionID domain.SessionID `json:"sessionId"`
-	Session   domain.Session   `json:"session"`
+	Session   SessionView      `json:"session"`
 }
 
 // KillSessionResponse is the body of POST /api/v1/sessions/{sessionId}/kill.

backend/internal/httpd/controllers/sessions.go

@@ -88,7 +88,7 @@ func (c *SessionsController) list(w http.ResponseWriter, r *http.Request) {
 		envelope.WriteError(w, r, err)
 		return
 	}
-	envelope.WriteJSON(w, http.StatusOK, ListSessionsResponse{Sessions: sessions})
+	envelope.WriteJSON(w, http.StatusOK, ListSessionsResponse{Sessions: sessionViews(sessions)})
 }
 
 func (c *SessionsController) spawn(w http.ResponseWriter, r *http.Request) {
@@ -117,7 +117,7 @@ func (c *SessionsController) spawn(w http.ResponseWriter, r *http.Request) {
 		envelope.WriteError(w, r, err)
 		return
 	}
-	envelope.WriteJSON(w, http.StatusCreated, SessionResponse{Session: sess})
+	envelope.WriteJSON(w, http.StatusCreated, SessionResponse{Session: sessionView(sess)})
 }
 
 func (c *SessionsController) get(w http.ResponseWriter, r *http.Request) {
@@ -130,7 +130,7 @@ func (c *SessionsController) get(w http.ResponseWriter, r *http.Request) {
 		envelope.WriteError(w, r, err)
 		return
 	}
-	envelope.WriteJSON(w, http.StatusOK, SessionResponse{Session: sess})
+	envelope.WriteJSON(w, http.StatusOK, SessionResponse{Session: sessionView(sess)})
 }
 
 func (c *SessionsController) listPRs(w http.ResponseWriter, r *http.Request) {
@@ -204,7 +204,7 @@ func (c *SessionsController) restore(w http.ResponseWriter, r *http.Request) {
 		envelope.WriteError(w, r, err)
 		return
 	}
-	envelope.WriteJSON(w, http.StatusOK, RestoreSessionResponse{OK: true, SessionID: sessionID(r), Session: sess})
+	envelope.WriteJSON(w, http.StatusOK, RestoreSessionResponse{OK: true, SessionID: sessionID(r), Session: sessionView(sess)})
 }
 
 func (c *SessionsController) kill(w http.ResponseWriter, r *http.Request) {
@@ -344,7 +344,7 @@ func (c *SessionsController) listOrchestrators(w http.ResponseWriter, r *http.Re
 		envelope.WriteError(w, r, err)
 		return
 	}
-	envelope.WriteJSON(w, http.StatusOK, ListSessionsResponse{Sessions: sessions})
+	envelope.WriteJSON(w, http.StatusOK, ListSessionsResponse{Sessions: sessionViews(sessions)})
 }
 
 func (c *SessionsController) getOrchestrator(w http.ResponseWriter, r *http.Request) {
@@ -361,7 +361,7 @@ func (c *SessionsController) getOrchestrator(w http.ResponseWriter, r *http.Requ
 		envelope.WriteAPIError(w, r, http.StatusNotFound, "not_found", "SESSION_NOT_FOUND", "Unknown session", nil)
 		return
 	}
-	envelope.WriteJSON(w, http.StatusOK, SessionResponse{Session: sess})
+	envelope.WriteJSON(w, http.StatusOK, SessionResponse{Session: sessionView(sess)})
 }
 
 func sessionID(r *http.Request) domain.SessionID {
@@ -432,6 +432,18 @@ func writeSessionPRError(w http.ResponseWriter, r *http.Request, err error) {
 	}
 }
 
+func sessionView(s domain.Session) SessionView {
+	return SessionView{Session: s, PRs: sessionPRFacts(s.PRs)}
+}
+
+func sessionViews(sessions []domain.Session) []SessionView {
+	out := make([]SessionView, 0, len(sessions))
+	for _, s := range sessions {
+		out = append(out, sessionView(s))
+	}
+	return out
+}
+
 func sessionPRFacts(prs []domain.PRFacts) []SessionPRFacts {
 	out := make([]SessionPRFacts, 0, len(prs))
 	for _, pr := range prs {