chore: document the --relative flag

Author: lqiu96

.kokoro/build.sh

@@ -157,7 +157,7 @@ case ${JOB_TYPE} in
     fi
     ;;
   graalvm-single)
-    generate_modified_modules_list false    
+    generate_modified_modules_list false
     if [[ "$(release_please_snapshot_pull_request)" == "true" ]]; then
       echo "Not running GraalVM checks -- this is Release Please SNAPSHOT pull request."
     elif [[ ! " ${modified_module_list[*]} " =~ " ${BUILD_SUBDIR} " ]]; then
@@ -200,7 +200,9 @@ case ${JOB_TYPE} in
     if [ -n "${BASE_SHA}" ] && [ -n "${HEAD_SHA}" ]; then
         # Optimize the build by identifying ONLY the Maven modules that contain changed Java source files.
         # Format those specific modules instead of the entire codebase, reducing format check time.
-        changed_file_list=$(git diff --name-only "${BASE_SHA}" "${HEAD_SHA}")
+        # The --relative flag is when building in the submodule as only files modified in the module
+        # should be accounted for.
+        changed_file_list=$(git diff --name-only "${BASE_SHA}" "${HEAD_SHA}" --relative)
         echo "${changed_file_list}"
 
         has_code_change="false"
@@ -232,17 +234,16 @@ case ${JOB_TYPE} in
                 done
                 if [ -f "${dir}/pom.xml" ] && [ "${dir}" != "." ]; then
                     # Filter out directories not participating in the default formatting reactor:
-                    # - samples/tutorials are wrapped in the include-samples profile
-                    # - proto-*/grpc-* are generated code and should not be formatted manually
+                    # - samples are handwritten by developers
+                    # - proto-*/grpc-* are generated code and should use the compiler format
                     # - *-bom/parents are POM-only and contain no Java source
                     if [[ "${dir}" != *"samples"* ]] && \
-                       [[ "${dir}" != *"tutorials"* ]] && \
                        [[ "$(basename "${dir}")" != "proto-google-"* ]] && \
                        [[ "$(basename "${dir}")" != "grpc-google-"* ]] && \
                        [[ "$(basename "${dir}")" != *"-bom" ]] && \
                        [[ "$(basename "${dir}")" != "google-cloud-pom-parent" ]] && \
                        [[ "$(basename "${dir}")" != "google-cloud-jar-parent" ]]; then
-                       
+
                         changed_modules+=("${dir}")
                     fi
                 fi
@@ -251,7 +252,7 @@ case ${JOB_TYPE} in
 
         echo "Changed Modules: ${changed_modules[*]}"
 
-        # Deduplicate the modules using sort -u, so that we pass a concise list of unique modules
+        # Deduplicate the modules using sort -u to pass a concise list of unique modules
         # via the Maven `-pl` argument.
         if [ ${#changed_modules[@]} -gt 0 ]; then
             unique_modules=$(printf '%s\n' "${changed_modules[@]}" | sort -u | paste -sd ',' -)
@@ -292,4 +293,4 @@ if [[ "${ENABLE_FLAKYBOT}" == "true" ]]; then
 fi
 
 echo "exiting with ${RETURN_CODE}"
-exit ${RETURN_CODE}
+exit ${RETURN_CODE}