diff --git a/etc/ci/taskcluster/curl-artifact.sh b/etc/ci/taskcluster/curl-artifact.sh
index ad180bbc7d7..3093eca4a87 100755
--- a/etc/ci/taskcluster/curl-artifact.sh
+++ b/etc/ci/taskcluster/curl-artifact.sh
@@ -1,13 +1,23 @@
-#!/bin/sh
-task_id="$1"
-artifact="$2"
+#!/usr/bin/env bash
+
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+task_id="${1}"
+artifact="${2}"
 shift 2
-url="https://queue.taskcluster.net/v1/task/${task_id}/artifacts/public/${artifact}"
-echo "Fetching $url" >&2
+queue="https://queue.taskcluster.net/v1"
+url="${queue}/task/${task_id}/artifacts/public/${artifact}"
+echo "Fetching ${url}" >&2
 curl \
     --retry 5 \
     --connect-timeout 10 \
     --location \
     --fail \
-    "$url" \
-    "$@"
+    "${url}" \
+    "${@}"
diff --git a/servo-tidy.toml b/servo-tidy.toml
index ac4cf0d345d..e62ae92a06d 100644
--- a/servo-tidy.toml
+++ b/servo-tidy.toml
@@ -68,6 +68,9 @@ files = [
   "./tests/wpt/mozilla/tests/css/fonts",
   "./tests/wpt/mozilla/tests/css/pre_with_tab.html",
   "./tests/wpt/mozilla/tests/mozilla/textarea_placeholder.html",
+  # Python 3 syntax causes "E901 SyntaxError" when flake8 runs in Python 2
+  "./etc/ci/taskcluster/decision-task.py",
+  "./etc/ci/taskcluster/decisionlib.py",
 ]
 # Directories that are ignored for the non-WPT tidy check.
 directories = [