Detox, part 1 of N (#12119)

* Don't use `tox` for `check-sampleconfig`
* Don't use `tox` for check-newsfragment

.github/workflows/tests.yml

@@ -10,12 +10,19 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
+  check-sampleconfig:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-python@v2
+      - run: pip install -e .
+      - run: scripts-dev/generate_sample_config --check
+
   lint:
     runs-on: ubuntu-latest
     strategy:
       matrix:
         toxenv:
-          - "check-sampleconfig"
           - "check_codestyle"
           - "check_isort"
           - "mypy"
@@ -43,15 +50,15 @@ jobs:
           ref: ${{ github.event.pull_request.head.sha }}
           fetch-depth: 0
       - uses: actions/setup-python@v2
-      - run: pip install tox
+      - run: "pip install 'towncrier>=18.6.0rc1'"
       - run: scripts-dev/check-newsfragment
         env:
           PULL_REQUEST_NUMBER: ${{ github.event.number }}
 
   # Dummy step to gate other tests on without repeating the whole list
   linting-done:
     if: ${{ !cancelled() }} # Run this even if prior jobs were skipped
-    needs: [lint, lint-crlf, lint-newsfile]
+    needs: [lint, lint-crlf, lint-newsfile, check-sampleconfig]
     runs-on: ubuntu-latest
     steps:
       - run: "true"

changelog.d/12119.misc

@@ -0,0 +1 @@
+Move CI checks out of tox, to facilitate a move to using poetry.

scripts-dev/check-newsfragment

@@ -35,7 +35,7 @@ CONTRIBUTING_GUIDE_TEXT="!! Please see the contributing guide for help writing y
 https://github.com/matrix-org/synapse/blob/develop/CONTRIBUTING.md#changelog"
 
 # If check-newsfragment returns a non-zero exit code, print the contributing guide and exit
-tox -qe check-newsfragment || (echo -e "$CONTRIBUTING_GUIDE_TEXT" >&2 && exit 1)
+python -m towncrier.check --compare-with=origin/develop || (echo -e "$CONTRIBUTING_GUIDE_TEXT" >&2 && exit 1)
 
 echo
 echo "--------------------------"

tox.ini

@@ -168,16 +168,6 @@ commands =
 extras = lint
 commands = isort -c --df {[base]lint_targets}
 
-[testenv:check-newsfragment]
-skip_install = true
-usedevelop = false
-deps = towncrier>=18.6.0rc1
-commands =
-   python -m towncrier.check --compare-with=origin/develop
-
-[testenv:check-sampleconfig]
-commands = {toxinidir}/scripts-dev/generate_sample_config --check
-
 [testenv:combine]
 skip_install = true
 usedevelop = false