fix(server): register the Linear write coordinate with host linear.app (RIG-4038)

go/internal/forge/linear.go

@@ -21,6 +21,10 @@ import (
 	"time"
 )
 
+// LinearHost is the forge-coordinate host of every Linear artifact. Webhook
+// events, the notify lane and the write lane must agree on it to join rows.
+const LinearHost = "linear.app"
+
 const (
 	// linearDefaultEndpoint is the public Linear GraphQL endpoint; LinearConfig.Host
 	// overrides it (the whole endpoint URL, not just a hostname).

go/internal/linearagent/data_event.go

@@ -95,7 +95,7 @@ func ParseLinearDataEvent(raw []byte) (ev forge.ForgeEvent, ok bool, err error)
 func parseLinearIssue(de dataEvent) (forge.ForgeEvent, bool, error) {
 	base := forge.ForgeEvent{
 		Provider: compassv1.ForgeProvider_FORGE_PROVIDER_LINEAR,
-		Host:     "linear.app",
+		Host:     forge.LinearHost,
 		Repo:     de.Data.Team.Key,
 		Kind:     compassv1internal.ForgeArtifactKind_FORGE_ARTIFACT_KIND_ISSUE,
 		Number:   de.Data.Number,
@@ -128,7 +128,7 @@ func parseLinearComment(de dataEvent) (forge.ForgeEvent, bool, error) {
 	iss := de.Data.Issue
 	base := forge.ForgeEvent{
 		Provider: compassv1.ForgeProvider_FORGE_PROVIDER_LINEAR,
-		Host:     "linear.app",
+		Host:     forge.LinearHost,
 		Repo:     iss.Team.Key,
 		Kind:     compassv1internal.ForgeArtifactKind_FORGE_ARTIFACT_KIND_ISSUE,
 		Number:   iss.Number,

go/server/forge_e2e_pgtest_test.go

@@ -62,7 +62,7 @@ func newForgeE2EWire(t *testing.T) *forgeE2EWire {
 
 	reg := newForgeProviderRegistry()
 	reg.register(forgeCoordinate{provider: compassv1.ForgeProvider_FORGE_PROVIDER_GITHUB, host: forgeE2EHost}, author, reviewer, true)
-	reg.register(forgeCoordinate{provider: compassv1.ForgeProvider_FORGE_PROVIDER_LINEAR}, linear, linear, false)
+	registerLinearForgeCoordinate(reg, linear)
 
 	// The chokepoint reads tracked issues off a store-backed issue projection
 	// (its own bus, distinct from the wire's). None of these writes are tracked,
@@ -421,3 +421,68 @@ func TestForgeLinearUnimplementedOverTheWire(t *testing.T) {
 		t.Fatalf("github author calls on a LINEAR-addressed call = %d, want 0 (ForgeRef must route to Linear)", len(w.author.Calls()))
 	}
 }
+
+// TestForgeLinearCreateIssueOverTheWire pins the Linear create arm's DL-055 row:
+// a Linear-addressed create_issue must record under the Linear host, whether the
+// ForgeRef leaves the host unset (registry default) or names it explicitly.
+func TestForgeLinearCreateIssueOverTheWire(t *testing.T) {
+	w := newForgeE2EWire(t)
+	ctx := w.ctx
+
+	cases := []struct {
+		name      string
+		ref       *compassv1.ForgeRef
+		requestID string
+		number    uint64
+	}{
+		{
+			name:      "unset host resolves the linear.app default",
+			ref:       &compassv1.ForgeRef{Provider: compassv1.ForgeProvider_FORGE_PROVIDER_LINEAR},
+			requestID: "req-linear-default-host",
+			number:    41,
+		},
+		{
+			name:      "explicit linear.app host resolves",
+			ref:       &compassv1.ForgeRef{Provider: compassv1.ForgeProvider_FORGE_PROVIDER_LINEAR, Host: "linear.app"},
+			requestID: "req-linear-explicit-host",
+			number:    42,
+		},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			w.linear.CreateIssueResult = forge.Issue{Number: tc.number, URL: "https://linear.app/rigel/issue/RIG-1"}
+
+			resp, err := w.supervisorClient.Forge(ctx, connect.NewRequest(&compassv1internal.ForgeCallRequest{
+				CallId:          "fc-" + tc.requestID,
+				ClientRequestId: tc.requestID,
+				Forge:           tc.ref,
+				Call: &compassv1internal.ForgeCallRequest_CreateIssue{CreateIssue: &compassv1internal.CreateIssueRequest{
+					Repo: "SEA", Title: "linear issue", Body: "b",
+				}},
+			}))
+			if err != nil {
+				t.Fatalf("Forge(linear create_issue) over the socket = %v", err)
+			}
+			if e := resp.Msg.GetError(); e != nil {
+				t.Fatalf("linear create_issue returned in-band error {code=%q msg=%q}, want an Issue arm", e.GetCode(), e.GetMessage())
+			}
+			if got := resp.Msg.GetIssue().GetForge().GetHost(); got != "linear.app" {
+				t.Fatalf("result forge host = %q, want linear.app", got)
+			}
+
+			art, ok, aerr := w.store.AuthoredArtifactByRequestID(ctx, w.supervisor.ID, tc.requestID)
+			if aerr != nil {
+				t.Fatalf("AuthoredArtifactByRequestID = %v", aerr)
+			}
+			if !ok {
+				t.Fatal("no DL-055 ownership row for the linear create, want one")
+			}
+			if art.Provider != store.ForgeProviderLinear || art.Host != "linear.app" {
+				t.Fatalf("row coordinate = (%v, %q), want (linear, linear.app)", art.Provider, art.Host)
+			}
+			if art.Number != tc.number {
+				t.Fatalf("row number = %d, want %d", art.Number, tc.number)
+			}
+		})
+	}
+}

go/server/serve.go

@@ -1794,7 +1794,7 @@ func buildLinearNotifyLane(
 	}
 	const (
 		provider = store.ForgeProviderLinear
-		host     = "linear.app"
+		host     = forge.LinearHost
 	)
 	client := forge.NewLinear(forge.LinearConfig{Token: tokens, Log: log})
 
@@ -2042,8 +2042,7 @@ func buildForgeWriteService(
 	// One client serves both roles, riding the SAME linearTokens instance (DEC-4).
 	// isDefault=false: GitHub is the default, Linear is selected explicitly.
 	if linearTokens != nil {
-		linear := forge.NewLinear(forge.LinearConfig{Token: linearTokens, Log: log})
-		registry.register(forgeCoordinate{provider: compassv1.ForgeProvider_FORGE_PROVIDER_LINEAR}, linear, linear, false)
+		registerLinearForgeCoordinate(registry, forge.NewLinear(forge.LinearConfig{Token: linearTokens, Log: log}))
 	}
 
 	return newForgeService(st, issueBrd, registry), nil
@@ -2060,6 +2059,13 @@ func registerGitHubForgeCoordinate(reg *forgeProviderRegistry, fc ForgeConfig, a
 	reg.register(forgeCoordinate{provider: compassv1.ForgeProvider_FORGE_PROVIDER_GITHUB, host: fc.Host}, author, reviewer, true)
 }
 
+// registerLinearForgeCoordinate registers the Linear write coordinate. It must
+// carry forge.LinearHost: the DL-055 row rejects an empty host. One client
+// serves both roles (Linear has no author/reviewer split).
+func registerLinearForgeCoordinate(reg *forgeProviderRegistry, linear forge.Provider) {
+	reg.register(forgeCoordinate{provider: compassv1.ForgeProvider_FORGE_PROVIDER_LINEAR, host: forge.LinearHost}, linear, linear, false)
+}
+
 // buildLinearTokenSource builds the ONE shared Linear OAuth client-credentials
 // token source (actor=app) from the declared client-id/secret pair, or returns
 // nil when Linear is not configured (neither name declared — the clean off-state

go/server/serve_forge_test.go

@@ -688,6 +688,9 @@ func TestForgeLinearLanesShareOneTokenSource(t *testing.T) {
 	if !ok {
 		t.Fatal("no Linear write coordinate registered with a configured token source")
 	}
+	if resolved.host != forge.LinearHost {
+		t.Fatalf("Linear coordinate resolved host %q, want %q (the DL-055 row rejects an empty host)", resolved.host, forge.LinearHost)
+	}
 	writeLinear, ok := resolved.author.(*forge.Linear)
 	if !ok {
 		t.Fatalf("Linear coordinate author is %T, want *forge.Linear", resolved.author)