Revert "Workaround for new pip 20.3 behavior"

This reverts commit 7a3a7ce876 and
bcd0acf6c0 and part of
f1ed7c77c5 which all cap our pip
installs.

Given the pip ecosystem can often incorporate major changes, tracking
upstream at least generally gives us one problem at a time to solve
rather than trying to handle version jumps when LTS distros update.

The new dependency resolver included some changes that disallow
setting URL's like "file:///path/to/project#egg=project" in
constraints.  Apparently the fact it used to work was an accident of
the requires/constraints mechanism; it does make some sense as the URL
doesn't really have a version-number that the resolver can put in an
ordering graph.

The _setup_package_with_constraints_edit function comment highlights
what this is trying to do

 # Updates the constraints from REQUIREMENTS_DIR to reflect the
 # future installed state of this package. This ensures when we
 # install this package we get the from source version.

In other words; if constraints has "foo==1.2.3" and Zuul has checked
out "foo" for testing, we have to make sure pip doesn't choose version
1.2.3 from pypi.

It seems like removing the entry from upper-requirements.txt is the
important part; adding the URL path to the on-disk version was just
something that seemed to work at the time, but isn't really necessary.
We will install the package in question which will be the latest
version (from Zuul checkout) and without the package in
upper-requirements.txt nothing will try and downgrade it.

Therefore the solution proposed here is to remove the adding of the
URL parts.

This allows us to uncap pip and restore testing with the new
dependency resolver.

Closes-Bug: #1906322
Change-Id: Ib9ba52147199a9d6d0293182d5db50c4a567d677

inc/python

@@ -378,12 +378,13 @@ function _setup_package_with_constraints_edit {
     project_dir=$(cd $project_dir && pwd)
 
     if [ -n "$REQUIREMENTS_DIR" ]; then
-        # Constrain this package to this project directory from here on out.
+        # Remove this package from constraints before we install it.
+        # That way, later installs won't "downgrade" the install from
+        # source we are about to do.
         local name
         name=$(awk '/^name.*=/ {print $3}' $project_dir/setup.cfg)
         $REQUIREMENTS_DIR/.venv/bin/edit-constraints \
-            $REQUIREMENTS_DIR/upper-constraints.txt -- $name \
-            "$flags file://$project_dir#egg=$name"
+            $REQUIREMENTS_DIR/upper-constraints.txt -- $name
     fi
 
     setup_package $bindep $project_dir "$flags" $extras

lib/tempest

@@ -718,9 +718,6 @@ function install_tempest {
     set_tempest_venv_constraints $tmp_u_c_m
 
     tox -r --notest -efull
-    # TODO: remove the trailing pip constraint when a proper fix
-    # arrives for bug https://bugs.launchpad.net/devstack/+bug/1906322
-    $TEMPEST_DIR/.tox/tempest/bin/pip install -U -r $RC_DIR/tools/cap-pip.txt
     # NOTE(mtreinish) Respect constraints in the tempest full venv, things that
     # are using a tox job other than full will not be respecting constraints but
     # running pip install -U on tempest requirements

tools/cap-pip.txt

@@ -1 +0,0 @@
-pip<20.3

tools/fixup_stuff.sh

@@ -155,8 +155,23 @@ function fixup_ovn_centos {
     yum_install centos-release-openstack-victoria
 }
 
+function fixup_ubuntu {
+    if ! is_ubuntu; then
+        return
+    fi
+
+    # Since pip10, pip will refuse to uninstall files from packages
+    # that were created with distutils (rather than more modern
+    # setuptools).  This is because it technically doesn't have a
+    # manifest of what to remove.  However, in most cases, simply
+    # overwriting works.  So this hacks around those packages that
+    # have been dragged in by some other system dependency
+    sudo rm -rf /usr/lib/python3/dist-packages/PyYAML-*.egg-info
+}
+
 function fixup_all {
     fixup_keystone
+    fixup_ubuntu
     fixup_fedora
     fixup_suse
 }

tools/install_pip.sh

@@ -91,9 +91,7 @@ function install_get_pip {
             die $LINENO "Download of get-pip.py failed"
         touch $LOCAL_PIP.downloaded
     fi
-    # TODO: remove the trailing pip constraint when a proper fix
-    # arrives for bug https://bugs.launchpad.net/devstack/+bug/1906322
-    sudo -H -E python${PYTHON3_VERSION} $LOCAL_PIP -c $TOOLS_DIR/cap-pip.txt
+    sudo -H -E python${PYTHON3_VERSION} $LOCAL_PIP
 }
 
 
@@ -130,11 +128,6 @@ if [[ -n $PYPI_ALTERNATIVE_URL ]]; then
     configure_pypi_alternative_url
 fi
 
-# Just use system pkgs on Focal
-if [[ "$DISTRO" == focal ]]; then
-    exit 0
-fi
-
 # Eradicate any and all system packages
 
 # Python in fedora/suse depends on the python-pip package so removing it