Default in CI to Py3, not Py2

.travis.yml

@@ -203,92 +203,92 @@ matrix:
     - <<: *default_test_config
       name: "Py2 - Unit tests for pants and pants-plugins"
       script:
-        - ./build-support/bin/travis-ci.sh -lp
+        - ./build-support/bin/travis-ci.sh -2lp
 
     - <<: *default_test_config
       name: "Py3 - Unit tests for pants and pants-plugins"
       script:
-        - ./build-support/bin/travis-ci.sh -3lp
+        - ./build-support/bin/travis-ci.sh -lp
 
     - <<: *default_test_config
       name: "Py2 - Python contrib tests"
       script:
-        - ./build-support/bin/travis-ci.sh -n
+        - ./build-support/bin/travis-ci.sh -2n
 
     - <<: *default_test_config
       name: "Py3 - Python contrib tests"
       script:
-        - ./build-support/bin/travis-ci.sh -3n
+        - ./build-support/bin/travis-ci.sh -n
 
     - <<: *default_test_config
       name: "Integration tests for pants - shard 1"
       script:
-        - ./build-support/bin/travis-ci.sh -c3 -i 0/7
+        - ./build-support/bin/travis-ci.sh -c -i 0/7
 
     - <<: *default_test_config
       name: "Integration tests for pants - shard 2"
       script:
-        - ./build-support/bin/travis-ci.sh -c3 -i 1/7
+        - ./build-support/bin/travis-ci.sh -c -i 1/7
 
     - <<: *default_test_config
       name: "Integration tests for pants - shard 3"
       script:
-        - ./build-support/bin/travis-ci.sh -c3 -i 2/7
+        - ./build-support/bin/travis-ci.sh -c -i 2/7
 
     - <<: *default_test_config
       name: "Integration tests for pants - shard 4"
       script:
-        - ./build-support/bin/travis-ci.sh -c3 -i 3/7
+        - ./build-support/bin/travis-ci.sh -c -i 3/7
 
     - <<: *default_test_config
       name: "Integration tests for pants - shard 5"
       script:
-        - ./build-support/bin/travis-ci.sh -c3 -i 4/7
+        - ./build-support/bin/travis-ci.sh -c -i 4/7
 
     - <<: *default_test_config
       name: "Integration tests for pants - shard 6"
       script:
-        - ./build-support/bin/travis-ci.sh -c3 -i 5/7
+        - ./build-support/bin/travis-ci.sh -c -i 5/7
 
     - <<: *default_test_config
       name: "Integration tests for pants - shard 7"
       script:
-        - ./build-support/bin/travis-ci.sh -c3 -i 6/7
+        - ./build-support/bin/travis-ci.sh -c -i 6/7
 
     - <<: *default_cron_test_config
       name: "Integration tests for pants (Python 2) - shard 1"
       script:
-        - ./build-support/bin/travis-ci.sh -c -i 0/7
+        - ./build-support/bin/travis-ci.sh -c2 -i 0/7
 
     - <<: *default_cron_test_config
       name: "Integration tests for pants (Python 2) - shard 2"
       script:
-        - ./build-support/bin/travis-ci.sh -c -i 1/7
+        - ./build-support/bin/travis-ci.sh -c2 -i 1/7
 
     - <<: *default_cron_test_config
       name: "Integration tests for pants (Python 2) - shard 3"
       script:
-        - ./build-support/bin/travis-ci.sh -c -i 2/7
+        - ./build-support/bin/travis-ci.sh -c2 -i 2/7
 
     - <<: *default_cron_test_config
       name: "Integration tests for pants (Python 2) - shard 4"
       script:
-        - ./build-support/bin/travis-ci.sh -c -i 3/7
+        - ./build-support/bin/travis-ci.sh -c2 -i 3/7
 
     - <<: *default_cron_test_config
       name: "Integration tests for pants (Python 2) - shard 5"
       script:
-        - ./build-support/bin/travis-ci.sh -c -i 4/7
+        - ./build-support/bin/travis-ci.sh -c2 -i 4/7
 
     - <<: *default_cron_test_config
       name: "Integration tests for pants (Python 2) - shard 6"
       script:
-        - ./build-support/bin/travis-ci.sh -c -i 5/7
+        - ./build-support/bin/travis-ci.sh -c2 -i 5/7
 
     - <<: *default_cron_test_config
       name: "Integration tests for pants (Python 2) - shard 7"
       script:
-        - ./build-support/bin/travis-ci.sh -c -i 6/7
+        - ./build-support/bin/travis-ci.sh -c2 -i 6/7
 
     # Rust on linux
     - <<: *linux_with_fuse

build-support/bin/ci.sh

@@ -13,10 +13,9 @@ function usage() {
   cat <<EOF
 Runs commons tests for local or hosted CI.
 
-Usage: $0 (-h|-3fxbkmrjlpuneycitzs)
+Usage: $0 (-h|-2fxbkmrjlpuneycitzs)
  -h           print out this help message
- -3           After pants is bootstrapped, set --python-setup-interpreter-constraints such that any
-              python tests run with Python 3.
+ -2           Run using Python 2 (defaults to using Python 3).
  -f           run python code formatting checks
  -x           run bootstrap clean-all (assume bootstrapping from a
               fresh clone)
@@ -64,12 +63,12 @@ bootstrap_compile_args=(
 python_unit_shard="0/1"
 python_contrib_shard="0/1"
 python_intg_shard="0/1"
-python_three="false"
+python_two="false"
 
-while getopts "h3fxbkmrjlpeasu:ny:ci:tz" opt; do
+while getopts "h2fxbkmrjlpeasu:ny:ci:tz" opt; do
   case ${opt} in
     h) usage ;;
-    3) python_three="true" ;;
+    2) python_two="true" ;;
     f) run_pre_commit_checks="true" ;;
     x) run_bootstrap_clean="true" ;;
     b) run_bootstrap="false" ;;
@@ -132,7 +131,7 @@ if [[ "${run_bootstrap:-true}" == "true" ]]; then
 fi
 
 # NB: Ordering matters here. We (currently) always bootstrap a Python 2 pex.
-if [[ "${python_three:-false}" == "true" ]]; then
+if [[ "${python_two:-false}" == "false" ]]; then
   banner "Setting interpreter constraints to Python 3!"
   export PANTS_PYTHON_SETUP_INTERPRETER_CONSTRAINTS='["CPython>=3.6,<4"]'
 else