build: skip dependency fan-out when only test fixtures change

When all changed files reside in test/fixtures/ directories, skip the
expensive dependency fan-out step in the affected-tests workflow.
Changes to test fixtures cannot affect downstream packages, so
searching for and testing all dependents is unnecessary and causes
CI timeouts when many packages are modified at once.

This also reverts the namespace CLI test exclusion from the previous
commit, as the fixture-only check addresses the root cause.

Assisted-by: Claude Opus 4.6 <noreply@anthropic.com>

---
type: pre_commit_static_analysis_report
description: Results of running static analysis checks when committing changes.
report:
  - task: lint_filenames
    status: passed
  - task: lint_editorconfig
    status: passed
  - task: lint_markdown
    status: na
  - task: lint_package_json
    status: na
  - task: lint_repl_help
    status: na
  - task: lint_javascript_src
    status: na
  - task: lint_javascript_cli
    status: na
  - task: lint_javascript_examples
    status: na
  - task: lint_javascript_tests
    status: na
  - task: lint_javascript_benchmarks
    status: na
  - task: lint_python
    status: na
  - task: lint_r
    status: na
  - task: lint_c_src
    status: na
  - task: lint_c_examples
    status: na
  - task: lint_c_benchmarks
    status: na
  - task: lint_c_tests_fixtures
    status: na
  - task: lint_shell
    status: missing_dependencies
  - task: lint_typescript_declarations
    status: passed
  - task: lint_typescript_tests
    status: na
  - task: lint_license_headers
    status: passed
---

Author: batpigandme

.github/workflows/scripts/run_affected_tests/run

@@ -122,23 +122,30 @@ main() {
 	# Extract package names from changed package directories (e.g., @stdlib/math/base/special/sin) by removing the leading 'lib/node_modules/':
 	packages=$(echo "${directories}" | sed -E 's/^lib\/node_modules\///')
 
-	# Find all package directories which `require()` one of the changed packages:
-	required_by=""
-	for package in ${packages}; do
-		echo "Finding packages which depend on '${package}'..."
-		escaped_package=$(echo "$package" | sed 's/[\/&]/\\&/g')
-		dependents=$(find lib/node_modules/@stdlib -type f -name '*.js' -exec grep -ol -E "require\( [']${escaped_package}['] \)" {} +) || true
-		echo "Found: ${dependents}"
-		if [ -n "${dependents}" ]; then
-			dependents=$(dirname $dependents | sed -E 's/\/(benchmark|bin|data|docs|etc|examples|include|lib|scripts|src|test)(\/.*)?$//' | sort -u)
-			echo "List of dependents: ${dependents}"
-			required_by="${required_by} ${dependents}"
+	# Determine whether any non-fixture files changed. If only test fixtures were modified, skip dependency fan-out since downstream packages cannot be affected:
+	non_fixture_files=$(echo "${changed}" | tr ' ' '\n' | grep -v '/test/fixtures/') || true
+
+	if [ -n "${non_fixture_files}" ]; then
+		# Find all package directories which `require()` one of the changed packages:
+		required_by=""
+		for package in ${packages}; do
+			echo "Finding packages which depend on '${package}'..."
+			escaped_package=$(echo "$package" | sed 's/[\/&]/\\&/g')
+			dependents=$(find lib/node_modules/@stdlib -type f -name '*.js' -exec grep -ol -E "require\( [']${escaped_package}['] \)" {} +) || true
+			echo "Found: ${dependents}"
+			if [ -n "${dependents}" ]; then
+				dependents=$(dirname $dependents | sed -E 's/\/(benchmark|bin|data|docs|etc|examples|include|lib|scripts|src|test)(\/.*)?$//' | sort -u)
+				echo "List of dependents: ${dependents}"
+				required_by="${required_by} ${dependents}"
+			fi
+		done
+
+		# Concatenate the list of changed package directories and package directories which `require()` one of the changed packages:
+		if [ -n "${required_by}" ]; then
+			directories="${directories} ${required_by}"
 		fi
-	done
-
-	# Concatenate the list of changed package directories and package directories which `require()` one of the changed packages:
-	if [ -n "${required_by}" ]; then
-		directories="${directories} ${required_by}"
+	else
+		echo 'Only test fixture files changed. Skipping dependency fan-out.' >&2
 	fi
 
 	# Build native add-ons for packages (if applicable):
@@ -164,9 +171,6 @@ main() {
 	# Exclude files residing in test fixtures directories:
 	files=$(echo "${files}" | grep -v '/fixtures/') || true
 
-	# Exclude the namespace CLI test, as it spawns child processes that dump the entire namespace and is too slow for affected-test runs:
-	files=$(echo "${files}" | tr ' ' '\n' | grep -v '@stdlib/namespace/test/test.cli.js' | tr '\n' ' ') || true
-
 	if [[ -n "${files}" ]]; then
 		# Invoke make in batches to avoid "Argument list too long" errors:
 		printf '%s\n' ${files} | xargs sh -c 'make test-javascript-files-min FILES="$*"' _