Fix changelog checker bugs

[changelog skip]

Author: dahlia

.travis.yml

@@ -8,11 +8,23 @@ script:
 - tox
 - tox -e docs
 - '[[ "$TRAVIS_TAG" = "" ]] || [[ "$TRAVIS_TAG" = "$(python setup.py --version)" ]]'
+# Ensure changelog was written:
 - |
-    if git show --format=%B --quiet "$TRAVIS_COMMIT_RANGE$TRAVIS_TAG" | grep '\[changelog skip\]' > /dev/null; then
-      echo "Skip changelog checker..."
+    if [[ "$TRAVIS_PULL_REQUEST" != "false" ]]; then
+      curl -L http://github.com/micha/jsawk/raw/master/jsawk > /tmp/jsawk
+      chmod +x /tmp/jsawk
+      PR_BASE="$(curl -vf https://api.github.com/repos/$TRAVIS_REPO_SLUG/pulls/$TRAVIS_PULL_REQUEST.json \
+                 | jq --raw-output '.base.sha')"
+      CHANGE_RANGE="${PR_BASE}..${TRAVIS_PULL_REQUEST_SHA}"
     elif [[ "$TRAVIS_TAG" != "" ]]; then
-      ! grep -i "to be released" README.rst
+      CHANGE_RANGE="${TRAVIS_TAG}^1..${TRAVIS_TAG}"
+    else
+      CHANGE_RANGE="${TRAVIS_COMMIT_RANGE}"
+    fi
+    if git show --format=%B --quiet "$CHANGE_RANGE" \
+       | grep '\[changelog skip\]' > /dev/null; then
+      echo "Skip changelog checker..."
     else
-      [[ "$(git diff --name-only "$TRAVIS_COMMIT_RANGE" | grep CHANGES\.rst)" != "" ]]
+      git diff --name-only "$CHANGE_RANGE" | grep CHANGES.rst
     fi
+- '[[ "$TRAVIS_TAG" = "" ]] || ! grep -i "to be released" CHANGES.rst'