shelve: split up dounshelve() in unshelvecmd() and _dounshelve()

I'd like to be able to override the new `_dounshelve()`, getting
access to the name of the shelve to unshelve. `unshelvecmd()` seems to
better match the existing `createcmd()`, `listcmd()` etc.

Differential Revision: https://phab.mercurial-scm.org/D8322

mercurial/commands.py

@@ -7585,7 +7585,7 b' def unshelve(ui, repo, *shelved, **opts)'
        unshelved.
     """
     with repo.wlock():
-        return shelvemod.dounshelve(ui, repo, *shelved, **opts)
+        return shelvemod.unshelvecmd(ui, repo, *shelved, **opts)
 
 
 statemod.addunfinished(

mercurial/shelve.py

@@ -1074,7 +1074,7 b' def _checkunshelveuntrackedproblems(ui, '
         raise error.Abort(m, hint=hint)
 
 
-def dounshelve(ui, repo, *shelved, **opts):
+def unshelvecmd(ui, repo, *shelved, **opts):
     opts = pycompat.byteskwargs(opts)
     abortf = opts.get(b'abort')
     continuef = opts.get(b'continue')
@@ -1121,6 +1121,10 b' def dounshelve(ui, repo, *shelved, **opt'
     if not shelvedfile(repo, basename, patchextension).exists():
         raise error.Abort(_(b"shelved change '%s' not found") % basename)
 
+    return _dounshelve(ui, repo, basename, opts)
+
+
+def _dounshelve(ui, repo, basename, opts):
     repo = repo.unfiltered()
     lock = tr = None
     try: