Speed up PR mutation responses

Author: julianknutsen

internal/sdk/additional_test.go

@@ -588,6 +588,49 @@ func TestDetailContext_UsesContextAwareCheckPR(t *testing.T) {
 	}
 }
 
+func TestPRMutations_DoNotRequireCheckPRContextForBranchDurability(t *testing.T) {
+	db := newFakeDB()
+	db.seedItem(fakeItem{
+		ID:          "w-1",
+		Title:       "Fix bug",
+		Status:      "claimed",
+		ClaimedBy:   "alice",
+		PostedBy:    "bob",
+		EffortLevel: "medium",
+	})
+
+	c := New(ClientConfig{
+		DB:        db,
+		RigHandle: "alice",
+		Mode:      "pr",
+		CheckPRContext: func(context.Context, string) string {
+			t.Fatal("CheckPRContext() should not be called on the mutation hot path")
+			return ""
+		},
+		CheckPR: func(string) string {
+			t.Fatal("CheckPR() should not be called on the mutation hot path")
+			return ""
+		},
+	})
+
+	result, err := c.Unclaim("w-1")
+	if err != nil {
+		t.Fatalf("Unclaim() error = %v", err)
+	}
+	if result.Detail == nil || result.Detail.Item == nil {
+		t.Fatal("expected mutation detail item")
+	}
+	if result.Detail.Item.Status != "open" {
+		t.Fatalf("status = %q, want open", result.Detail.Item.Status)
+	}
+	if result.Detail.Branch == "" {
+		t.Fatal("expected branch to persist when branch diverges from main")
+	}
+	if result.Detail.Delta == "" {
+		t.Fatal("expected non-empty delta for branch mutation")
+	}
+}
+
 func TestDetail_UsesSingleJoinedQuery(t *testing.T) {
 	var calls int
 	db := &queryOnlyDB{

internal/sdk/mutate.go

@@ -2,7 +2,6 @@ package sdk
 
 import (
 	"bytes"
-	"context"
 	"fmt"
 	"io"
 	"strings"
@@ -158,9 +157,10 @@ func (c *Client) mutatePRResult(wantedID, branch, mainStatus string) *MutationRe
 		detail.Actions = commons.AvailableTransitions(item, c.rigHandle)
 		detail.Delta = commons.ComputeDelta(mainStatus, item.Status, true)
 	}
-	if branch != "" {
-		detail.PRURL = c.checkPRContext(context.Background(), branch)
-	}
+	// Skip PR lookup on mutation responses. On large repos, finding an existing
+	// PR requires paging through upstream pulls and can dominate mutation
+	// latency even though the branch write has already succeeded. Detail reads
+	// still resolve PRURL on demand.
 	if branch != "" && c.BranchURL != nil {
 		detail.BranchURL = c.BranchURL(branch)
 	}

internal/sdk/sdk_test.go

@@ -1836,11 +1836,15 @@ func TestBranchActions_PRMode_WithPR(t *testing.T) {
 	})
 
 	// Claim creates a branch with a delta.
-	result, err := c.Claim("w-1")
-	if err != nil {
+	if _, err := c.Claim("w-1"); err != nil {
 		t.Fatalf("Claim: %v", err)
 	}
-	d := result.Detail
+	// Detail lookups still resolve the existing PR and should suppress
+	// submit_pr from branch actions.
+	d, err := c.Detail("w-1")
+	if err != nil {
+		t.Fatalf("Detail: %v", err)
+	}
 	// PR mode + delta + existing PR → discard only
 	if len(d.BranchActions) != 1 {
 		t.Fatalf("expected 1 branch action, got %v", d.BranchActions)