Also build the repo with Bzlmod enabled

.bazelci/presubmit.yml

@@ -7,7 +7,8 @@ matrix:
     - windows
 
 tasks:
-  ubuntu1804_bazel400:
+  ubuntu1804_bazel540:
+    name: Ubuntu with minimum supported Bazel version
     platform: ubuntu1804
     bazel: 5.4.0 # test minimum supported version of bazel
     shell_commands:
@@ -20,6 +21,7 @@ tasks:
       - "-//tests/core/nogo/bzlmod/..."
   ubuntu2004:
     # enable some unflipped incompatible flags on this platform to ensure we don't regress.
+    name: Ubuntu with --config=incompatible
     shell_commands:
       - tests/core/cgo/generate_imported_dylib.sh
     build_flags:
@@ -30,6 +32,23 @@ tasks:
       - "//..."
     test_targets:
       - "//..."
+  ubuntu2004_bzlmod:
+    name: Ubuntu with Bzlmod
+    platform: ubuntu2004
+    shell_commands:
+      - tests/core/cgo/generate_imported_dylib.sh
+    build_flags:
+      - "--enable_bzlmod"
+    build_targets:
+      - "//..."
+      - "-//tests/extras/gomock:all"
+      - "-//tests/integration/googleapis:all"
+    test_flags:
+      - "--enable_bzlmod"
+    test_targets:
+      - "//..."
+      - "-//tests/extras/gomock:all"
+      - "-//tests/integration/googleapis:all"
   debian11_zig_cc:
     platform: debian11
     shell_commands:

.bazelrc

@@ -1,8 +1,11 @@
 common --enable_platform_specific_config
+test --test_output=errors
 # TODO: Temporarily disable while rules_go migrates to Bzlmod for its dev build.
 # https://github.com/bazelbuild/bazel/issues/18958
 common --noexperimental_enable_bzlmod
-test --test_output=errors
+# rules_go is not typically used as a root module, so we want our
+# dependency versions to be as low as possible.
+common --check_direct_dependencies=off
 
 # Go requires a C toolchain that accepts options and emits errors like
 # gcc or clang. The Go SDK does not support MSVC.