issue #587: use deadsnakes PPA Python because VSTS version is junk

.ci/azure-pipelines-steps.yml

@@ -5,17 +5,25 @@ parameters:
   sign: false
 
 steps:
-- task: UsePythonVersion@0
-  inputs:
-    versionSpec: '$(python.version)'
-    architecture: 'x64'
+- script: "PYTHONVERSION=$(python.version) .ci/prep_azure.py"
+  displayName: "Run prep_azure.py"
+
+# The VSTS-shipped Pythons available via UsePythonVErsion are pure garbage,
+# broken symlinks, incorrect permissions and missing codecs. So we use the
+# deadsnakes PPA to get sane Pythons, and setup a virtualenv to install our
+# stuff into. The virtualenv can probably be removed again, but this was a
+# hard-fought battle and for now I am tired of this crap.
+- script: |
+    sudo ln -fs /usr/bin/python$(python.version) /usr/bin/python
+    /usr/bin/python -m pip install -U virtualenv setuptools wheel
+    /usr/bin/python -m virtualenv /tmp/venv -p /usr/bin/python$(python.version)
+    echo "##vso[task.prependpath]/tmp/venv/bin"
+
+  displayName: activate venv
 
 - script: .ci/spawn_reverse_shell.py
   displayName: "Spawn reverse shell"
 
-- script: .ci/prep_azure.py
-  displayName: "Run prep_azure.py"
-
 - script: .ci/$(MODE)_install.py
   displayName: "Run $(MODE)_install.py"
 

.ci/prep_azure.py

@@ -34,14 +34,15 @@ if ci_lib.have_apt():
         'echo force-unsafe-io | sudo tee /etc/dpkg/dpkg.cfg.d/nosync',
         'sudo add-apt-repository ppa:deadsnakes/ppa',
         'sudo apt-get update',
-        'sudo apt-get -y install python2.6 python2.6-dev libsasl2-dev libldap2-dev',
+        'sudo apt-get -y install '
+            'python{pv} '
+            'python{pv}-dev '
+            'libsasl2-dev '
+            'libldap2-dev '
+            .format(pv=os.environ['PYTHONVERSION'])
     ])
 
 
-#batches.append([
-    #'pip install -r dev_requirements.txt',
-#])
-
 if ci_lib.have_docker():
     batches.extend(
         ['docker pull %s' % (ci_lib.image_for_distro(distro),)]