travis: Run docs CI on py37

We were running it on py36 as a bit of manual bin-packing to optimize
total CI runtime, but sphinx-on-py36 has some bugs in annotation
introspection that we run into.

diff --git a/.travis.yml b/.travis.yml
index 6dd58ddd300dacb0ef4075cdbf54da2bf37bb305..4362c45ece49dd4ac7d04efbbde18f69ae2e141e 100644 (file)
--- a/.travis.yml
+++ b/.travis.yml
@@ -44,11 +44,12 @@ install:
     - if [[ $TRAVIS_PYTHON_VERSION != 'pypy'* ]]; then travis_retry pip install pycurl; fi
     # Twisted is flaky on pypy (TODO: still? this note is quite old)
     - if [[ $TRAVIS_PYTHON_VERSION != 'pypy'* ]]; then travis_retry pip install Twisted; fi
-    # Ideally we'd run the docs/lint stuff on the latest Python
+    # Ideally we'd run the lint stuff on the latest Python
     # version supported. But Python 3.7 requires slower-to-start VMs,
     # so we run it on 3.6 to minimize total CI run time.
-    - if [[ $TRAVIS_PYTHON_VERSION == '3.6' ]]; then travis_retry pip install -r docs/requirements.txt; fi
     - if [[ $TRAVIS_PYTHON_VERSION == '3.6' ]]; then travis_retry pip install flake8 mypy==0.630 black; fi
+    # We run docs on py37 because we need some bug fixes for introspection of annotations.
+    - if [[ $TRAVIS_PYTHON_VERSION == '3.7' ]]; then travis_retry pip install -r docs/requirements.txt; fi
     # On travis the extension should always be built
     - if [[ $TRAVIS_PYTHON_VERSION != 'pypy'* ]]; then export TORNADO_EXTENSION=1; fi
     - travis_retry python setup.py install
@@ -91,8 +92,8 @@ script:
     # make coverage reports for Codecov to find
     - if [[ "$RUN_COVERAGE" == 1 ]]; then coverage xml; fi
     - export TORNADO_EXTENSION=0
-    - if [[ $TRAVIS_PYTHON_VERSION == 3.6 ]]; then (cd ../docs && mkdir sphinx-out && sphinx-build -E -n -W -b html . sphinx-out); fi
-    - if [[ $TRAVIS_PYTHON_VERSION == 3.6 ]]; then (cd ../docs && mkdir sphinx-doctest-out && sphinx-build -E -n -b doctest . sphinx-out); fi
+    - if [[ $TRAVIS_PYTHON_VERSION == 3.7 ]]; then (cd ../docs && mkdir sphinx-out && sphinx-build -E -n -W -b html . sphinx-out); fi
+    - if [[ $TRAVIS_PYTHON_VERSION == 3.7 ]]; then (cd ../docs && mkdir sphinx-doctest-out && sphinx-build -E -n -b doctest . sphinx-out); fi
     - if [[ $TRAVIS_PYTHON_VERSION == '3.6' ]]; then (cd .. && flake8); fi
     - if [[ $TRAVIS_PYTHON_VERSION == '3.6' ]]; then (cd .. && black --check --diff tornado); fi
     - if [[ $TRAVIS_PYTHON_VERSION == '3.6' ]]; then (cd .. && mypy tornado); fi