benchmarks: tweak per-PR benchmark regression check based on pr-check

We can't run them all. It's too much.

Signed-off-by: Stephan Renatus <stephan.renatus@gmail.com>

.github/workflows/benchmarks.yaml

@@ -15,6 +15,7 @@ jobs:
     runs-on: ubuntu-24.04
     outputs:
       go: ${{ steps.changes.outputs.go }}
+      bench: ${{ steps.changes.outputs.bench }}
     steps:
       - name: Check out code
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
@@ -57,11 +58,14 @@ jobs:
           'data.policy["pr-check"]' > opa_result.json
 
           go_result=$(jq -r '.changes.go // false' opa_result.json)
+          bench_result=$(jq -c '.changes.bench // []' opa_result.json)
 
           echo "go=${go_result}" >> $GITHUB_OUTPUT
+          echo "bench=${bench_result}" >> $GITHUB_OUTPUT
 
           echo "Final outputs:"
           echo "  go=${go_result}"
+          echo "  bench=${bench_result}"
 
   benchmarks:
     permissions:
@@ -81,7 +85,7 @@ jobs:
     name: Check for regressions
     runs-on: ubuntu-24.04
     needs: [check-changes]
-    if: ${{ needs.check-changes.outputs.go == 'true' }}
+    if: ${{ needs.check-changes.outputs.bench != '' && needs.check-changes.outputs.bench != '[]' }}
     steps:
       - name: Check out code
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
@@ -104,8 +108,9 @@ jobs:
         env:
           BEFORE_SHA: ${{ github.event.before }}
           AFTER_SHA: ${{ github.event.after }}
+          BENCH_PKGS: ${{ needs.check-changes.outputs.bench }}
         run: |
-          for pkg in ./v1/rego ./v1/topdown ./v1/ast; do
+          for pkg in $(echo "$BENCH_PKGS" | jq -r '.[]'); do
             benchlab \
               -commit "$BEFORE_SHA","$AFTER_SHA" \
               -pkg "$pkg" \

build/policy/pr-check/pr_check.rego

@@ -63,7 +63,7 @@ go_root_files := [
 	"main.go",
 ]
 
-changes["docs"] if {
+changes.docs if {
 	some changed_file in input
 	startswith(changed_file.filename, "docs/")
 } else if {
@@ -71,7 +71,7 @@ changes["docs"] if {
 	changed_file.filename in docs_root_files
 }
 
-changes["go"] if {
+changes.go if {
 	some changed_file in input
 	endswith(changed_file.filename, ".go")
 } else if {
@@ -83,7 +83,7 @@ changes["go"] if {
 	changed_file.filename in go_root_files
 }
 
-changes["wasm"] if {
+changes.wasm if {
 	some changed_file in input
 	strings.any_prefix_match(changed_file.filename, wasm_change_prefixes)
 } else if {
@@ -91,7 +91,7 @@ changes["wasm"] if {
 	changed_file.filename in rego_and_wasm_change_root_files
 }
 
-changes["rego"] if {
+changes.rego if {
 	some changed_file in input
 	endswith(changed_file.filename, ".rego")
 } else if {
@@ -99,7 +99,25 @@ changes["rego"] if {
 	changed_file.filename in rego_and_wasm_change_root_files
 }
 
-changes["yaml"] if {
+changes.yaml if {
 	some changed_file in input
 	strings.any_suffix_match(changed_file.filename, yaml_change_suffixes)
 }
+
+changes.bench contains "./v1/ast" if {
+	some changed_file in input
+	startswith(changed_file.filename, "v1/ast/")
+	endswith(changed_file.filename, ".go")
+}
+
+changes.bench contains "./v1/topdown" if {
+	some changed_file in input
+	startswith(changed_file.filename, "v1/topdown/")
+	endswith(changed_file.filename, ".go")
+}
+
+changes.bench contains "./v1/rego" if {
+	some changed_file in input
+	startswith(changed_file.filename, "v1/rego/")
+	endswith(changed_file.filename, ".go")
+}

build/policy/pr-check/pr_check_test.rego

@@ -47,6 +47,14 @@ example_gh_actions_changelist := [
 	{"filename": ".github/workflows/pull-request.yaml"},
 ]
 
+example_bench_ast_changelist := [{"filename": "v1/ast/parser.go"}]
+
+example_bench_topdown_changelist := [{"filename": "v1/topdown/eval.go"}]
+
+example_bench_rego_changelist := [{"filename": "v1/rego/rego.go"}]
+
+example_bench_no_match_changelist := [{"filename": "cmd/build.go"}]
+
 test_run_docs_check_expect if {
 	pr_check.changes.docs with input as example_docs_changelist
 }
@@ -94,3 +102,20 @@ test_run_all_tests_expect if {
 	pr_check.changes.wasm with input as example_all_checks_root_changelist
 	not pr_check.changes.yaml with input as example_all_checks_root_changelist
 }
+
+test_bench_ast_only if {
+	pr_check.changes.bench == {"./v1/ast"} with input as example_bench_ast_changelist
+}
+
+test_bench_topdown_only if {
+	pr_check.changes.bench == {"./v1/topdown"} with input as example_bench_topdown_changelist
+}
+
+test_bench_rego_only if {
+	pr_check.changes.bench == {"./v1/rego"} with input as example_bench_rego_changelist
+}
+
+test_bench_no_match if {
+	pr_check.changes.go with input as example_bench_no_match_changelist
+	pr_check.changes.bench == set() with input as example_bench_no_match_changelist
+}