tools: do not lint commit message if var undefined

Trott · rvagg · commit 22043ccb8401 · 2018-11-28T11:26:48.000+11:00
Check that $TRAVIS_COMMIT_RANGE is set before trying to lint commit messages in Travis CI. Refs: #23572 (comment) Refs: #22842 (comment) PR-URL: #23725 Reviewed-By: Anatoli Papirovski <apapirovski@mac.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Luigi Pinca <luigipinca@gmail.com> Reviewed-By: Matheus Marchini <mat@mmarchini.me>
diff --git a/.travis.yml b/.travis.yml
@@ -13,7 +13,7 @@ matrix:
       script:
         - make lint
         # Lint the first commit in the PR.
-        - git log $TRAVIS_COMMIT_RANGE --pretty=format:'%h' --no-merges | tail -1 | xargs npx core-validate-commit --no-validate-metadata
+        - \[ -z "$TRAVIS_COMMIT_RANGE" \] || git log $TRAVIS_COMMIT_RANGE --pretty=format:'%h' --no-merges | tail -1 | xargs npx core-validate-commit --no-validate-metadata
     - name: "Test Suite"
       install:
         - ./configure
