main.star: fix up top-level edge case for files related to vendored code

The good news is that CL 594615 works on paths like src/cmd/go.mod; see
CL 594635. The bad news, I realize now, is that I fumbled the top-level
edge case. Fix it.

For golang/go#42661.

Change-Id: Ie993d5789b3185e822a254ee8953c25ed9055ebe
Reviewed-on: https://go-review.googlesource.com/c/build/+/594616
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>

Author: dmitshur

generated/commit-queue.cfg

@@ -29340,12 +29340,12 @@ config_groups {
         location_filters {
           gerrit_host_regexp: "go-review.googlesource.com"
           gerrit_project_regexp: "^go$"
-          path_regexp: "src/.+/go[.](mod|sum)"
+          path_regexp: "src(|/.+)/go[.](mod|sum)"
         }
         location_filters {
           gerrit_host_regexp: "go-review.googlesource.com"
           gerrit_project_regexp: "^go$"
-          path_regexp: "src/.+/vendor/.+"
+          path_regexp: "src(|/.+)/vendor/.+"
         }
         location_filters {
           gerrit_host_regexp: "go-review.googlesource.com"
@@ -29387,12 +29387,12 @@ config_groups {
         location_filters {
           gerrit_host_regexp: "go-review.googlesource.com"
           gerrit_project_regexp: "^go$"
-          path_regexp: "src/.+/go[.](mod|sum)"
+          path_regexp: "src(|/.+)/go[.](mod|sum)"
         }
         location_filters {
           gerrit_host_regexp: "go-review.googlesource.com"
           gerrit_project_regexp: "^go$"
-          path_regexp: "src/.+/vendor/.+"
+          path_regexp: "src(|/.+)/vendor/.+"
         }
         location_filters {
           gerrit_host_regexp: "go-review.googlesource.com"
@@ -29411,12 +29411,12 @@ config_groups {
         location_filters {
           gerrit_host_regexp: "go-review.googlesource.com"
           gerrit_project_regexp: "^go$"
-          path_regexp: "src/.+/go[.](mod|sum)"
+          path_regexp: "src(|/.+)/go[.](mod|sum)"
         }
         location_filters {
           gerrit_host_regexp: "go-review.googlesource.com"
           gerrit_project_regexp: "^go$"
-          path_regexp: "src/.+/vendor/.+"
+          path_regexp: "src(|/.+)/vendor/.+"
         }
         location_filters {
           gerrit_host_regexp: "go-review.googlesource.com"
@@ -29528,12 +29528,12 @@ config_groups {
         location_filters {
           gerrit_host_regexp: "go-review.googlesource.com"
           gerrit_project_regexp: "^go$"
-          path_regexp: "src/.+/go[.](mod|sum)"
+          path_regexp: "src(|/.+)/go[.](mod|sum)"
         }
         location_filters {
           gerrit_host_regexp: "go-review.googlesource.com"
           gerrit_project_regexp: "^go$"
-          path_regexp: "src/.+/vendor/.+"
+          path_regexp: "src(|/.+)/vendor/.+"
         }
         location_filters {
           gerrit_host_regexp: "go-review.googlesource.com"
@@ -29703,12 +29703,12 @@ config_groups {
         location_filters {
           gerrit_host_regexp: "go-review.googlesource.com"
           gerrit_project_regexp: "^go$"
-          path_regexp: "src/.+/go[.](mod|sum)"
+          path_regexp: "src(|/.+)/go[.](mod|sum)"
         }
         location_filters {
           gerrit_host_regexp: "go-review.googlesource.com"
           gerrit_project_regexp: "^go$"
-          path_regexp: "src/.+/vendor/.+"
+          path_regexp: "src(|/.+)/vendor/.+"
         }
         location_filters {
           gerrit_host_regexp: "go-review.googlesource.com"

main.star

@@ -804,8 +804,8 @@ RUN_MODS = dict(
             "build": [],
             "go": [
                 # Enable longtest builders on go against tip if files related to vendored code are modified.
-                "src/.+/go[.](mod|sum)",
-                "src/.+/vendor/.+",
+                "src(|/.+)/go[.](mod|sum)",
+                "src(|/.+)/vendor/.+",
                 "src/.+_bundle.go",
                 # Enable longtest builders on go against tip if files in the crypto/tls tree are modified,
                 # so that the BoGo test suite is run.