fix: remove install_id when app is deleted

scm/github/installation.go

@@ -22,6 +22,9 @@ func (c *client) ProcessInstallation(ctx context.Context, request *http.Request,
 
 	errs := []error{}
 
+	// if action is "deleted" then the RepositoriesAdded field will indicate the repositories that
+	// need to have install_id set to zero
+
 	// set install_id for repos added to the installation
 	for _, repo := range webhook.Installation.RepositoriesAdded {
 		r, err := db.GetRepoForOrg(ctx, webhook.Installation.Org, repo)
@@ -34,7 +37,14 @@ func (c *client) ProcessInstallation(ctx context.Context, request *http.Request,
 			continue
 		}
 
-		err = updateRepoInstallationID(ctx, webhook, r, db, webhook.Installation.ID)
+		installID := webhook.Installation.ID
+
+		// clear install_id if the installation is deleted
+		if webhook.Installation.Action == "deleted" {
+			installID = 0
+		}
+
+		err = updateRepoInstallationID(ctx, webhook, r, db, installID)
 		if err != nil {
 			errs = append(errs, err)
 		}

scm/github/webhook.go

@@ -543,6 +543,7 @@ func (c *client) processRepositoryEvent(h *api.Hook, payload *github.RepositoryE
 	}, nil
 }
 
+// processInstallationEvent is a helper function to process the installation event.
 func (c *client) processInstallationEvent(ctx context.Context, h *api.Hook, payload *github.InstallationEvent) (*internal.Webhook, error) {
 	h.SetEvent(constants.EventRepository)
 	h.SetEventAction(payload.GetAction())
@@ -563,6 +564,7 @@ func (c *client) processInstallationEvent(ctx context.Context, h *api.Hook, payl
 	}, nil
 }
 
+// processInstallationRepositoriesEvent is a helper function to process the installation repositories event.
 func (c *client) processInstallationRepositoriesEvent(ctx context.Context, h *api.Hook, payload *github.InstallationRepositoriesEvent) (*internal.Webhook, error) {
 	install := new(internal.Installation)