move author check to top; add hint about GitHub UI

.buildkite/linux/check_contributors

@@ -7,11 +7,18 @@ antispam=", at the domain "
 headAuthor=$(git log -1 --pretty=format:'%ae')
 authorAt=$(echo "$headAuthor" | sed "s/@/$antispam/")
 if git log --pretty=format:'%ae' CONTRIBUTORS | grep -i "$headAuthor" > /dev/null; then
-    echo "Author $authorAt found in CONTRIBUTORS"
+    echo "Author found in CONTRIBUTORS"
 else
     echo "All contributors:"
     git log --pretty=format:' - %ae' CONTRIBUTORS |sort |uniq |sort -f | sed "s/@/$antispam/"
 
     echo "Author $authorAt NOT found in list"
+    echo
+    cat <<EOF
+Please make sure you modify the CONTRIBUTORS file using the email address you
+are committing from. If you have GitHub configured to hide your email address,
+you may need to make a change to the CONTRIBUTORS file using the GitHub UI,
+then try again.
+EOF
     exit 1
 fi

.buildkite/linux/entrypoint

@@ -3,6 +3,9 @@
 set -e
 set -x
 
+# check author has added themselves to CONTRIBUTORS
+.buildkite/linux/check_contributors
+
 BAZEL="bazel --output_user_root=/state/bazel --output_base=/state/bazel/anki"
 BUILDARGS="--config=ci --experimental_convenience_symlinks=ignore"
 
@@ -14,6 +17,3 @@ $BAZEL test $BUILDARGS ...
 
 # if tests succeed, back up node_modules folder
 mv ts/node_modules /state/
-
-# check author has added themselves to CONTRIBUTORS
-.buildkite/linux/check_contributors