ci(tests): pull the gitleaks image with retries

.github/workflows/tests.yml

@@ -72,6 +72,8 @@ permissions:
 env:
   # ESP-IDF v5.5.1, pinned by digest; same image as build.yml
   IDF_IMAGE: espressif/idf:v5.5.1@sha256:dfa2d076c796769c07c155eba6c672b9f395aec943b2ba3701b73379b5f9e884
+  # gitleaks v8.28.0 (secret-scan), pinned by digest
+  GITLEAKS_IMAGE: zricethezav/gitleaks:v8.28.0@sha256:cdbb7c955abce02001a9f6c9f602fb195b7fadc1e812065883f695d1eeaba854
   ESP_IDF_SBOM_VERSION: 1.4.0
   ACTIONLINT_VERSION: 1.7.12
   ACTIONLINT_SHA256: 8aca8db96f1b94770f1b0d72b6dddcb1ebb8123cb3712530b08cc387b349a3d8
@@ -358,6 +360,14 @@ jobs:
         with:
           # The base commit must be present for gitleaks to diff against it.
           fetch-depth: 0
+      - name: Pull gitleaks image (retries transient registry errors)
+        run: |
+          for attempt in 1 2 3 4; do
+            docker pull "$GITLEAKS_IMAGE" && exit 0
+            echo "Pull failed (attempt $attempt), retrying..."
+            sleep $((attempt * 15))
+          done
+          exit 1
       # Range: base..head for a pull request, before..after for a push; a new branch or a
       # force-push has no usable "before", so only the pushed commit is scanned. Context
       # values arrive via env, never interpolated into the script.
@@ -376,5 +386,5 @@ jobs:
           echo "Scanning commit range: $RANGE"
           docker run --rm -v "$PWD:/repo" \
             -e GIT_CONFIG_COUNT=1 -e GIT_CONFIG_KEY_0=safe.directory -e GIT_CONFIG_VALUE_0='*' \
-            zricethezav/gitleaks:v8.28.0@sha256:cdbb7c955abce02001a9f6c9f602fb195b7fadc1e812065883f695d1eeaba854 \
+            "$GITLEAKS_IMAGE" \
             git /repo --redact --no-banner --log-opts="$RANGE"

test/guards/test_supply_chain.py

@@ -73,6 +73,19 @@ def test_image_variables_and_known_images_pinned(self):
                 with self.subTest(workflow=name, image=ref):
                     self.assertRegex(ref, r"@sha256:[0-9a-f]{64}$")
 
+    def test_run_images_pulled_with_retries(self):
+        # A registry hiccup (Docker Hub auth timeout) must not fail the gate: `docker run`
+        # takes its image from an *_IMAGE variable that a retry loop pulled first.
+        for name, text in repo.workflows().items():
+            code = re.sub(r"(?m)\s#\s.*$", "", text).replace("\\\n", " ")
+            for cmd in re.findall(r"docker run\b[^\n]*", code):
+                with self.subTest(workflow=name, run=cmd[:60]):
+                    self.assertNotRegex(cmd, r"\s[\w.-]+/[\w.-]+:[\w.-]+@sha256:",
+                                        "run images through an *_IMAGE variable")
+                    for var in re.findall(r'"\$(\w*IMAGE\w*)"', cmd):
+                        self.assertRegex(code, r'for attempt in [^\n]*\n\s*docker pull "\$' + var + r'" && exit 0',
+                                         f"pull ${var} with retries before running it")
+
     def test_workflows_default_to_read_only_token(self):
         for name, text in repo.workflows().items():
             with self.subTest(workflow=name):