[PR #10013/4b9373f6 backport][stable-10] Homebrew: Emit a useful error message if brew info reports a package tap is null.

changelogs/fragments/10012-improve-error-handling-homebrew-missing-tap.yml

@@ -0,0 +1,2 @@
+bugfixes:
+  - homebrew - emit a useful error message if ``brew info`` reports a package tap is ``null`` (https://github.com/ansible-collections/community.general/pull/10013, https://github.com/ansible-collections/community.general/issues/10012).

plugins/modules/homebrew.py

@@ -399,10 +399,15 @@ def _extract_package_name(self, package_detail, is_cask):
             name = package_detail["name"]
             full_name = package_detail["full_name"]
 
-        tapped_name = package_detail["tap"] + "/" + name
+        # Issue https://github.com/ansible-collections/community.general/issues/9803:
+        # name can include the tap as a prefix, in order to disambiguate,
+        # e.g. casks from identically named formulae.
+        #
+        # Issue https://github.com/ansible-collections/community.general/issues/10012:
+        # package_detail["tap"] is None if package is no longer available.
+        tapped_name = [package_detail["tap"] + "/" + name] if package_detail["tap"] else []
         aliases = package_detail.get("aliases", [])
-
-        package_names = set([name, full_name, tapped_name] + aliases)
+        package_names = set([name, full_name] + tapped_name + aliases)
 
         # Finally, identify which of all those package names was the one supplied by the user.
         package_names = package_names & set(self.packages)