ci: Travis: simplify/improve Python/pip setup (#10228)

* ci/before_install.sh: do not (try to) upgrade pip

  It is not necessary usually (for our use case(s)), and rather good to
  have this (implicitly) pinned.

* Simplify/improve Python info output

* Use pyenv-global to activate/use Python 2.7/7.7

* simplify pip-install of neovim, also for osx

2 files changed, 31 insertions, 32 deletions

diff --git a/ci/before_install.sh b/ci/before_install.sh
index d8cf38d314..79738d8bbf 100755
--- a/ci/before_install.sh
+++ b/ci/before_install.sh
@@ -7,28 +7,34 @@ if [[ "${CI_TARGET}" == lint ]]; then
   exit
 fi
 
-echo 'python info:'
+echo 'Python info:'
 (
-  2>&1 python --version || true
-  2>&1 python2 --version || true
-  2>&1 python3 --version || true
-  2>&1 pip --version || true
-  2>&1 pip2 --version || true
-  2>&1 pip3 --version || true
-  echo 'pyenv versions:'
-  2>&1 pyenv versions || true
-) | sed 's/^/  /'
-
-if [[ "${TRAVIS_OS_NAME}" == osx ]]; then
-  echo "Upgrade Python 3 pip"
-  python3 -m pip -q install --user --upgrade pip
-else
-  echo "Upgrade Python 2 pip"
-  python2.7 -m pip -q install --user --upgrade pip
-  echo "Upgrade Python 3 pip"
-  # Allow failure. pyenv pip3 on travis is broken:
-  # https://github.com/travis-ci/travis-ci/issues/8363
-  python3 -m pip -q install --user --upgrade pip || true
+  set -x
+  python3 --version
+  python2 --version
+  python --version
+  pip3 --version
+  pip2 --version
+  pip --version
+  pyenv versions
+) 2>&1 | sed 's/^/  /' || true
+
+# Use pyenv, but not for OSX on Travis, where it only has the "system" version.
+if [[ "${TRAVIS_OS_NAME}" != osx ]] && command -v pyenv; then
+  echo 'Setting Python versions via pyenv'
+  # Prefer python2 as python for /usr/bin/asan_symbolize-4.0.
+  pyenv global 2.7.15:3.7
+
+  echo 'Updated Python info:'
+  (
+    set -x
+    python3 --version
+    python2 --version
+    python --version
+
+    pip3 --version
+    pip2 --version
+  ) 2>&1 | sed 's/^/  /'
 fi
 
 echo "Install node (LTS)"
diff --git a/ci/install.sh b/ci/install.sh
index 12985098cd..27a8aa05c1 100755
--- a/ci/install.sh
+++ b/ci/install.sh
@@ -11,18 +11,11 @@ if [[ "${TRAVIS_OS_NAME}" == osx ]]; then
   export PATH="/usr/local/opt/ccache/libexec:$PATH"
 fi
 
+# Use default CC to avoid compilation problems when installing Python modules.
 echo "Install neovim module for Python 3."
-# Allow failure. pyenv pip3 on travis is broken:
-# https://github.com/travis-ci/travis-ci/issues/8363
-CC=cc python3 -m pip -q install --user --upgrade neovim || true
-
-if ! [ "${TRAVIS_OS_NAME}" = osx ] ; then
-  # Update PATH for pip.
-  export PATH="$(python2.7 -c 'import site; print(site.getuserbase())')/bin:$PATH"
-  # Use default CC to avoid compilation problems when installing Python modules.
-  echo "Install neovim module for Python 2."
-  CC=cc python2.7 -m pip -q install --user --upgrade neovim
-fi
+CC=cc pip3 -q install --user --upgrade neovim
+echo "Install neovim module for Python 2."
+CC=cc pip2 -q install --user --upgrade neovim
 
 echo "Install neovim RubyGem."
 gem install --no-document --version ">= 0.8.0" neovim