feat(webapp): deprecate v3 CLI deploys server-side

Detect deploys coming from v3 CLI versions (payloads that omit the
'type' field) and, when DEPRECATE_V3_CLI_DEPLOYS_ENABLED=1, reject them
with a clear error that points to the migration docs. Enforcement is
gated so we can observe v3 deploy traffic via logs before flipping.

v4 CLIs always send 'type' ('MANAGED' or 'V1') on /api/v1/deployments,
so they are unaffected. Verified against the CLI source for 4.0.0,
4.0.1, 4.0.5, 4.1.0, 4.2.0, and 4.4.4.

Author: ericallam

.server-changes/deprecate-v3-cli-deploys.md

@@ -0,0 +1,6 @@
+---
+area: webapp
+type: breaking
+---
+
+Add server-side deprecation gate for deploys from v3 CLI versions (gated by `DEPRECATE_V3_CLI_DEPLOYS_ENABLED`). v4 CLI deploys are unaffected.

apps/webapp/app/env.server.ts

@@ -348,6 +348,12 @@ const EnvironmentSchema = z
       .int()
       .default(60 * 1000 * 15), // 15 minutes
 
+    // When enabled, reject deploys made by v3 CLI versions (i.e. payloads that
+    // omit the `type` field). v4 CLI versions always send `type` ("MANAGED" or "V1"),
+    // so they are unaffected. Defaults to off so detection can run in
+    // log-only mode before enforcement.
+    DEPRECATE_V3_CLI_DEPLOYS_ENABLED: z.string().default("0"),
+
     OBJECT_STORE_BASE_URL: z.string().optional(),
     OBJECT_STORE_BUCKET: z.string().optional(),
     OBJECT_STORE_ACCESS_KEY_ID: z.string().optional(),

apps/webapp/app/v3/services/initializeDeployment.server.ts

@@ -59,6 +59,28 @@ export class InitializeDeploymentService extends BaseService {
         };
       }
 
+      // v4 CLI versions always send `payload.type` ("MANAGED" or "V1"). v3 CLI
+      // versions never do, so the absence of `type` is a reliable signal that
+      // the request came from a 3.x CLI. Detection always runs (so we can
+      // observe how many deploys are still using v3), enforcement is gated
+      // behind DEPRECATE_V3_CLI_DEPLOYS_ENABLED so it can be rolled out safely.
+      if (!payload.type) {
+        const enforced = env.DEPRECATE_V3_CLI_DEPLOYS_ENABLED === "1";
+
+        logger.warn("Detected deploy from deprecated v3 CLI", {
+          environmentId: environment.id,
+          projectId: environment.projectId,
+          organizationId: environment.project.organizationId,
+          enforced,
+        });
+
+        if (enforced) {
+          throw new ServiceValidationError(
+            "The trigger.dev CLI v3 is no longer supported for deployments. Please upgrade your project to v4: https://trigger.dev/docs/migrating-from-v3"
+          );
+        }
+      }
+
       if (payload.type === "UNMANAGED") {
         throw new ServiceValidationError("UNMANAGED deployments are not supported");
       }