Use common code to detect envs

This commit adds a parent-class function which makes the calculation of
environment names identical regardless of the provider being used. The
function simply accepts a list of the ref paths (i.e. refs/heads/foo,
refs/remotes/origin/bar, refs/tags/baz).

This commit also makes a slight tweak to how dulwich determines which
ref paths to use for env detection. Before it used any ref with a path
beginning with refs/heads or refs/tags, but this switches it to
refs/remotes so that the common logic introduced in the new function
described above works.

It seems that dulwich adds local heads for any remote heads pulled down
when the remote is fetched, which is why this would have worked for env
detection before.

This commit contains a more complete fix for #27432, as an earlier
commit only fixed this for pygit2.

salt/utils/gitfs.py

@@ -269,6 +269,35 @@ class GitProvider(object):
             log.critical(msg, exc_info_on_loglevel=logging.DEBUG)
             failhard(self.role)
 
+    def _get_envs_from_ref_paths(self, refs):
+        '''
+        Return the names of remote refs (stripped of the remote name) and tags
+        which are exposed as environments. If a branch or tag matches
+        '''
+        def _check_ref(env_set, base_ref, rname):
+            '''
+            Check the ref and resolve it as the base_ref if it matches. If the
+            resulting env is exposed via whitelist/blacklist, add it to the
+            env_set.
+            '''
+            if base_ref is not None and base_ref == rname:
+                rname = 'base'
+            if self.env_is_exposed(rname):
+                env_set.add(rname)
+
+        ret = set()
+        base_ref = getattr(self, 'base', None)
+        for ref in refs:
+            ref = re.sub('^refs/', '', ref)
+            rtype, rname = ref.split('/', 1)
+            if rtype == 'remotes':
+                parted = rname.partition('/')
+                rname = parted[2] if parted[2] else parted[0]
+                _check_ref(ret, base_ref, rname)
+            elif rtype == 'tags':
+                _check_ref(ret, base_ref, rname)
+        return ret
+
     def check_root(self):
         '''
         Check if the relative root path exists in the checked-out copy of the
@@ -542,18 +571,8 @@ class GitPython(GitProvider):
         Check the refs and return a list of the ones which can be used as salt
         environments.
         '''
-        ret = set()
-        for ref in self.repo.refs:
-            parted = ref.name.partition('/')
-            rspec = parted[2] if parted[2] else parted[0]
-            if isinstance(ref, git.Head):
-                if hasattr(self, 'base') and self.base == rspec:
-                    rspec = 'base'
-                if self.env_is_exposed(rspec):
-                    ret.add(rspec)
-            elif isinstance(ref, git.Tag) and self.env_is_exposed(rspec):
-                ret.add(rspec)
-        return ret
+        ref_paths = [x.path for x in self.repo.refs]
+        return self._get_envs_from_ref_paths(ref_paths)
 
     def fetch(self):
         '''
@@ -908,29 +927,8 @@ class Pygit2(GitProvider):
         Check the refs and return a list of the ones which can be used as salt
         environments.
         '''
-        def _check_ref(env_set, base_ref, rname):
-            '''
-            Check the ref and resolve it as the base_ref if it matches. If the
-            resulting env is exposed via whitelist/blacklist, add it to the
-            env_set.
-            '''
-            if base_ref is not None and base_ref == rname:
-                rname = 'base'
-            if self.env_is_exposed(rname):
-                env_set.add(rname)
-
-        ret = set()
-        base_ref = getattr(self, 'base', None)
-        for ref in self.repo.listall_references():
-            ref = re.sub('^refs/', '', ref)
-            rtype, rname = ref.split('/', 1)
-            if rtype == 'remotes':
-                parted = rname.partition('/')
-                rname = parted[2] if parted[2] else parted[0]
-                _check_ref(ret, base_ref, rname)
-            elif rtype == 'tags':
-                _check_ref(ret, base_ref, rname)
-        return ret
+        ref_paths = self.repo.listall_references()
+        return self._get_envs_from_ref_paths(ref_paths)
 
     def fetch(self):
         '''
@@ -1203,7 +1201,7 @@ class Dulwich(GitProvider):  # pylint: disable=abstract-method
     def __init__(self, opts, remote, per_remote_defaults,
                  override_params, cache_root, role='gitfs'):
         self.get_env_refs = lambda refs: [
-            x for x in refs if re.match('refs/(heads|tags)', x)
+            x for x in refs if re.match('refs/(remotes|tags)', x)
             and not x.endswith('^{}')
         ]
         self.provider = 'dulwich'
@@ -1251,18 +1249,8 @@ class Dulwich(GitProvider):  # pylint: disable=abstract-method
         Check the refs and return a list of the ones which can be used as salt
         environments.
         '''
-        ret = set()
-        for ref in self.get_env_refs(self.repo.get_refs()):
-            # ref will be something like 'refs/heads/master'
-            rtype, rspec = ref[5:].split('/', 1)
-            if rtype == 'heads':
-                if hasattr(self, 'base') and self.base == rspec:
-                    rspec = 'base'
-                if self.env_is_exposed(rspec):
-                    ret.add(rspec)
-            elif rtype == 'tags' and self.env_is_exposed(rspec):
-                ret.add(rspec)
-        return ret
+        ref_paths = self.get_env_refs(self.repo.get_refs())
+        return self._get_envs_from_ref_paths(ref_paths)
 
     def fetch(self):
         '''