apt: fix virtual package install version detection (#76781)

* apt: fix virtual package install version detection

Change 4a62c4e3e4 introduced version
matching in installation.

The problem stems from

 if version_installable or version:
     pkg_list.append("'%s=%s'" % (name, version_installable or version))

When the package is a virtual-package, package_status() is returning
the "version_installable" of the package *satisfying* the
virtual-package; but then this is trying to install the
virtual-package with this version pin.

For example, "yaml-mode" is a virtual package satisifed by
"elpa-yaml-mode" (currently 0.0.14-1) and trying to install it fails
with

 $ usr/bin/apt-get -y ... install 'yaml-mode=0.0.14-1'
 ... failed: E: Version '0.0.14-1' for 'yaml-mode' was not found ...

In the case of a virtual-package with nothing installed to satisfy it,
we should just return blank values to allow apt-get to do it's thing.

The tests are updated to install and remove this package.

Fixes: #76779

changelogs/fragments/apt_virtual_fix.yml

@@ -0,0 +1,2 @@
+bugfixes:
+  - apt module now correctly handles virtual packages.

lib/ansible/modules/apt.py

@@ -510,17 +510,20 @@ def package_status(m, pkgname, version_cmp, version, default_release, cache, sta
             try:
                 provided_packages = cache.get_providing_packages(pkgname)
                 if provided_packages:
-                    is_installed = False
+                    # When this is a virtual package satisfied by only
-                    version_installable = None
+                    # one installed package, return the status of the target
-                    version_ok = False
+                    # package to avoid requesting re-install
-                    # when virtual package providing only one package, look up status of target package
                     if cache.is_virtual_package(pkgname) and len(provided_packages) == 1:
                         package = provided_packages[0]
-                        installed, version_ok, version_installable, has_files = \
+                        installed, installed_version, version_installable, has_files = \
                             package_status(m, package.name, version_cmp, version, default_release, cache, state='install')
                         if installed:
-                            is_installed = True
+                            return installed, installed_version, version_installable, has_files
-                    return is_installed, version_ok, version_installable, False
+
+                    # Otherwise return nothing so apt will sort out
+                    # what package to satisfy this with
+                    return False, False, None, False
+
                 m.fail_json(msg="No package matching '%s' is available" % pkgname)
             except AttributeError:
                 # python-apt version too old to detect virtual packages

test/integration/targets/apt/tasks/apt.yml

@@ -507,3 +507,25 @@
     that:
       - "allow_change_held_packages_no_update is not changed"
       - "allow_change_held_packages_hello_version.stdout == allow_change_held_packages_hello_version_again.stdout"
+
+# Virtual package
+- name: Install a virtual package
+  apt:
+    package:
+      - emacs-nox
+      - yaml-mode # <- the virtual package
+    state: latest
+  register: install_virtual_package_result
+
+- name: Check the virtual package install result
+  assert:
+    that:
+      - install_virtual_package_result is changed
+
+- name: Clean up virtual-package install
+  apt:
+    package:
+      - emacs-nox
+      - elpa-yaml-mode
+    state: absent
+    purge: yes