backout: backed out changeset 5d83a40cd3f8

backout: backed out changeset 5d83a40cd3f8

This is the re-send of the backout in D11757 that I accidentally queued. I'll
rewrite the original commit message:

...sigh

We do not have Python 3 packaging for thg on Windows where the vast majority of
of users use the thg installer for Mercurial. Until this is done (hopefully
this cycle), we're keeping Python.

(end of the old commit message)

On top of this, we have a solid lead to have competent people take care of this
packaging issue for us in time for the 6.1 release, which is really the main
reason for us to wait. We're trying our best to make this work, so please bear
with us.

Differential Revision: https://phab.mercurial-scm.org/D11770

--- a/contrib/heptapod-ci.yml	Wed Nov 24 05:00:28 2021 +0100
+++ b/contrib/heptapod-ci.yml	Mon Nov 22 10:47:12 2021 +0100
@@ -5,7 +5,7 @@
 image: registry.heptapod.net/mercurial/ci-images/mercurial-core:$HG_CI_IMAGE_TAG
 
 variables:
-    PYTHON: python3
+    PYTHON: python
     TEST_HGMODULEPOLICY: "allow"
     HG_CI_IMAGE_TAG: "latest"
     TEST_HGTESTS_ALLOW_NETIO: "0"
@@ -30,17 +30,30 @@
         - echo "$RUNTEST_ARGS"
         - HGTESTS_ALLOW_NETIO="$TEST_HGTESTS_ALLOW_NETIO" HGMODULEPOLICY="$TEST_HGMODULEPOLICY" "$PYTHON" tests/run-tests.py --color=always $RUNTEST_ARGS
 
-checks:
+checks-py2:
     <<: *runtests
     variables:
         RUNTEST_ARGS: "--time --test-list /tmp/check-tests.txt"
 
-rust-cargo-test:
+checks-py3:
+    <<: *runtests
+    variables:
+        RUNTEST_ARGS: "--time --test-list /tmp/check-tests.txt"
+        PYTHON: python3
+
+rust-cargo-test-py2: &rust_cargo_test
     <<: *all
     stage: tests
     script:
+        - echo "python used, $PYTHON"
         - make rust-tests
 
+rust-cargo-test-py3:
+    stage: tests
+    <<: *rust_cargo_test
+    variables:
+        PYTHON: python3
+
 phabricator-refresh:
     stage: phabricator
     variables:
@@ -54,40 +67,71 @@
             ./contrib/phab-refresh-stack.sh --comment "$DEFAULT_COMMENT";
         fi
 
-test:
+test-py2:
     <<: *runtests
     variables:
         RUNTEST_ARGS: " --no-rust --blacklist /tmp/check-tests.txt"
         TEST_HGMODULEPOLICY: "c"
         TEST_HGTESTS_ALLOW_NETIO: "1"
 
-test-pure:
+test-py3:
+    <<: *runtests
+    variables:
+        RUNTEST_ARGS: " --no-rust --blacklist /tmp/check-tests.txt"
+        PYTHON: python3
+        TEST_HGMODULEPOLICY: "c"
+        TEST_HGTESTS_ALLOW_NETIO: "1"
+
+test-py2-pure:
     <<: *runtests
     variables:
         RUNTEST_ARGS: "--pure --blacklist /tmp/check-tests.txt"
         TEST_HGMODULEPOLICY: "py"
 
-test-rust:
+test-py3-pure:
+    <<: *runtests
+    variables:
+        RUNTEST_ARGS: "--pure --blacklist /tmp/check-tests.txt"
+        PYTHON: python3
+        TEST_HGMODULEPOLICY: "py"
+
+test-py2-rust:
     <<: *runtests
     variables:
         HGWITHRUSTEXT: cpython
         RUNTEST_ARGS: "--rust --blacklist /tmp/check-tests.txt"
         TEST_HGMODULEPOLICY: "rust+c"
 
-test-rhg:
+test-py3-rust:
+    <<: *runtests
+    variables:
+        HGWITHRUSTEXT: cpython
+        RUNTEST_ARGS: "--rust --blacklist /tmp/check-tests.txt"
+        PYTHON: python3
+        TEST_HGMODULEPOLICY: "rust+c"
+
+test-py3-rhg:
     <<: *runtests
     variables:
         HGWITHRUSTEXT: cpython
         RUNTEST_ARGS: "--rust --rhg --blacklist /tmp/check-tests.txt"
+        PYTHON: python3
         TEST_HGMODULEPOLICY: "rust+c"
 
-test-chg:
+test-py2-chg:
     <<: *runtests
     variables:
         RUNTEST_ARGS: "--blacklist /tmp/check-tests.txt --chg"
         TEST_HGMODULEPOLICY: "c"
 
-check-pytype:
+test-py3-chg:
+    <<: *runtests
+    variables:
+        PYTHON: python3
+        RUNTEST_ARGS: "--blacklist /tmp/check-tests.txt --chg"
+        TEST_HGMODULEPOLICY: "c"
+
+check-pytype-py3:
     extends: .runtests_template
     before_script:
       - hg clone . /tmp/mercurial-ci/ --noupdate --config phases.publish=no
@@ -98,6 +142,7 @@
     variables:
         RUNTEST_ARGS: " --allow-slow-tests tests/test-check-pytype.t"
         HGTEST_SLOWTIMEOUT: "3600"
+        PYTHON: python3
         TEST_HGMODULEPOLICY: "c"
 
 # `sh.exe --login` sets a couple of extra environment variables that are defined