Hack up interpreter selection in non-default UCS python 2.7 wheel bui…

…lding shards for Linux and OSX.

.travis.yml

@@ -596,6 +596,8 @@ py27_osx_build_wheels_ucs4: &py27_osx_build_wheels_ucs4
     - PYTHON_CONFIGURE_OPTS=--enable-unicode=ucs4
     # We set $PY to ensure the UCS4 interpreter is used when bootstrapping the PEX.
     - PY=${PYENV_ROOT}/shims/python2.7
+    # We hack selection of the the UCS4 interpreter by Pants with this constraint.
+    - PANTS_PYTHON_SETUP_INTERPRETER_CONSTRAINTS="['2.7.13']"
   before_install:
     - curl -L https://github.com/stedolan/jq/releases/download/jq-1.5/jq-osx-amd64 -o /usr/local/bin/jq
     - chmod 755 /usr/local/bin/jq

build-support/docker/travis_ci_py27_ucs2/Dockerfile

@@ -30,6 +30,11 @@ ENV PATH "${PYENV_ROOT}/shims:${PATH}"
 ENV PY "${PYENV_ROOT}/shims/python2.7"
 ENV PEX_PYTHON_PATH "${PYENV_ROOT}/shims/python2.7"
 
+# We hack selection of the the UCS4 interpreter by Pants with the interpreter constraint.
+# This hack may be un-neccessary due to setting PEX_PYTHON_PATH above, but we add it for
+# (non-local :/) symmetry with .travis.yml setup of said-same for the non-default UCS OSX shard.
+ENV PANTS_PYTHON_SETUP_INTERPRETER_CONSTRAINTS "['2.7.13']"
+
 # Setup mount points for the travis ci user & workdir.
 VOLUME /travis/home
 VOLUME /travis/workdir

build-support/travis/travis.yml.mustache

@@ -543,6 +543,8 @@ py27_osx_build_wheels_ucs4: &py27_osx_build_wheels_ucs4
     - PYTHON_CONFIGURE_OPTS=--enable-unicode=ucs4
     # We set $PY to ensure the UCS4 interpreter is used when bootstrapping the PEX.
     - PY=${PYENV_ROOT}/shims/python2.7
+    # We hack selection of the the UCS4 interpreter by Pants with this constraint.
+    - PANTS_PYTHON_SETUP_INTERPRETER_CONSTRAINTS="['2.7.13']"
   before_install:
     {{>before_install_osx}}
     - ./build-support/bin/install_python_for_ci.sh 2.7.13 ${PYENV_PY36_VERSION}