Update automator exclude check to exclude files in PR causing event

prow/config/jobs/api.yaml

@@ -20,6 +20,7 @@ jobs:
     - --labels=auto-merge,release-notes-none
     - --modifier=update_api_dep
     - --token-path=/etc/github-token/oauth
+    - --git-exclude=^common/
     - --cmd=go get istio.io/api@$AUTOMATOR_SHA && go mod tidy && make clean gen
     requirements: [github]
     repos: [istio/test-infra@master]

prow/config/jobs/client-go.yaml

@@ -23,7 +23,7 @@ jobs:
     - --labels=auto-merge,release-notes-none
     - --modifier=update_client-go_dep
     - --token-path=/etc/github-token/oauth
-    - --git-exclude=common
+    - --git-exclude=^common/
     - --cmd=go get istio.io/client-go@$AUTOMATOR_SHA && go mod tidy && make clean gen
     requirements: [github]
     repos: [istio/test-infra@master]

prow/config/jobs/gogo-genproto.yaml

@@ -23,7 +23,7 @@ jobs:
     - --labels=auto-merge,release-notes-none
     - --modifier=update_gogo-genproto_dep
     - --token-path=/etc/github-token/oauth
-    - --git-exclude=common
+    - --git-exclude=^common/
     - --cmd=go get istio.io/gogo-genproto@$AUTOMATOR_SHA && go mod tidy && make clean gen
     requirements: [github]
     repos: [istio/test-infra@master]

prow/config/jobs/pkg.yaml

@@ -26,7 +26,7 @@ jobs:
     - --labels=auto-merge,release-notes-none
     - --modifier=update_pkg_dep
     - --token-path=/etc/github-token/oauth
-    - --git-exclude=common
+    - --git-exclude=^common/
     - --cmd=go get istio.io/pkg@$AUTOMATOR_SHA && go mod tidy && make clean gen
     requirements: [github]
     repos: [istio/test-infra@master]

prow/config/jobs/proxy.yaml

@@ -66,6 +66,7 @@ jobs:
   - --labels=auto-merge,release-notes-none
   - --modifier=update_proxy_dep
   - --token-path=/etc/github-token/oauth
+  - --git-exclude=^common/
   - --cmd=bin/update_proxy.sh $AUTOMATOR_SHA
   requirements: [github]
   repos: [istio/test-infra@master]

tools/automator/README.md

@@ -57,7 +57,7 @@ The following is a list of supported options for `automator.sh`. If an option is
 | `--verbose`     |            | Enable verbose output. Print commands and their arguments as they are executed. **WARNING**: this has the potential to print sensitive data to standard output.                                                                                             |                                                                                                 |
 | `--strict`      |            | Enable strict mode. When enabled, if the command does not produce a [git diff] it will exit with a non-zero exit code.                                                                                                                                      |                                                                                                 |
 | `--dry-run`     |            | Enable dry run mode. When enabled, the command will terminate early and **NOT** perform a commit, push, or pull request for any changes. This is useful for local testing/debugging or when concerned only with the [git diff] or exit code of the command. |                                                                                                 |
-| `--git-exclude` | string | Added to `git diff` to exclude a file/path when detrining changes | `common` |
+| `--git-exclude` | string | Applied to list of file changes in the commit CAUSING this automator run using grep -vE '\<string\>'. If no additional changes remain, the automator task will stop. | `^common/`<br> `^pkg/\|^pilot/`|
 
 ### Environment Variables
 

tools/automator/automator.sh

@@ -118,7 +118,7 @@ get_opts() {
       shift
       ;;
     --git-exclude)
-      git_exclude=(":^$2")
+      git_exclude="$2"
       shift 2
       ;;
     --)
@@ -196,7 +196,7 @@ validate_opts() {
   fi
 
   if [ -z "${git_exclude:-}" ]; then
-    git_exclude=()
+    git_exclude=""
   fi
 }
 
@@ -237,7 +237,7 @@ add_labels() {
 
 commit() {
   if $dry_run; then
-    git diff --cached "${git_exclude[@]}"
+    git diff --cached
     return 0
   fi
 
@@ -280,6 +280,18 @@ merge() {
   fi
 }
 
+# validate_changes_exist_in_latest_commit validates changes exist in the prior commit after removing files specified
+# in the git_exclude list. If no files remain after exclusion, the automation script exits.
+validate_changes_exist_in_latest_commit() {
+  if [ -n "$git_exclude" ]; then
+    changes=$(git show --name-only --pretty=oneline | sed 1d | grep -cvE "$git_exclude") # need to remove first line
+    if [ "${changes}" -eq 0 ]
+    then
+      print_error_and_exit "No changes remaining in upstream PR after excluding" 0  # not really an error so return 0
+    fi
+  fi
+}
+
 work() { (
   set -e
 
@@ -305,7 +317,7 @@ work() { (
 
     git add --all
 
-    if ! git diff --cached --quiet --exit-code "${git_exclude[@]}"; then
+    if ! git diff --cached --quiet --exit-code; then
       commit
     elif $strict; then
       print_error "no diff for $repo" 1
@@ -323,6 +335,7 @@ main() {
   get_opts "$@"
   validate_opts
   export_globals
+  validate_changes_exist_in_latest_commit
 
   AUTOMATOR_ROOT_DIR="$(pwd)"