store: return just one filename in walk functions Various walk functions return `(revlog_type, decoded, encoded)` where decoded could be None. But no-one cares about `encoded` and expects `unencoded` to be present, except verify (because this can only happen with old repo formats). Simplify all this by either failing outright if a decoding a filename fails (instead of almost certainly failing with a type error due to treating None as a bytes), or skipping the filename but providing in an out argument for hg verify. Differential Revision: https://phab.mercurial-scm.org/D11248

--- a/mercurial/repair.py	Sun Aug 01 10:57:21 2021 -0400
+++ b/mercurial/repair.py	Mon Aug 02 08:05:13 2021 -0400
@@ -433,7 +433,7 @@
     if scmutil.istreemanifest(repo):
         # This logic is safe if treemanifest isn't enabled, but also
         # pointless, so we skip it if treemanifest isn't enabled.
-        for t, unencoded, encoded, size in repo.store.datafiles():
+        for t, unencoded, size in repo.store.datafiles():
             if unencoded.startswith(b'meta/') and unencoded.endswith(
                 b'00manifest.i'
             ):