diff mercurial/revset.py @ 49511:117dcc4a0e67

revset: handle wdir() in `sort(..., -topo)`

The last apparent usage of `repo.changelog.parentrevs` in revsets is in
`children()`, but since the sets being operated on never include wdir(), it's
never called with `wdirrev` and the wdir() arg on the command line is
effectively ignored instead of aborting there.  I'm not sure how to fix that.

Before (on a clone of hg):

    $ python3.8 hg perf::revset --config extensions.perf=contrib/perf.py 'sort(all(), -topo)'
    ! wall 0.123663 comb 0.130000 user 0.130000 sys 0.000000 (best of 76)

After:

    $ python3.8 hg perf::revset --config extensions.perf=contrib/perf.py 'sort(all(), -topo)'
    ! wall 0.123838 comb 0.130000 user 0.130000 sys 0.000000 (best of 75)

--- a/mercurial/revset.py	Mon Oct 03 17:24:52 2022 -0400
+++ b/mercurial/revset.py	Tue Oct 04 12:34:50 2022 -0400
@@ -2474,10 +2474,20 @@
         return revs
     elif keyflags[0][0] == b"topo":
         firstbranch = ()
+        parentrevs = repo.changelog.parentrevs
+        parentsfunc = parentrevs
+        if wdirrev in revs:
+
+            def parentsfunc(r):
+                try:
+                    return parentrevs(r)
+                except error.WdirUnsupported:
+                    return [p.rev() for p in repo[None].parents()]
+
         if b'topo.firstbranch' in opts:
             firstbranch = getset(repo, subset, opts[b'topo.firstbranch'])
         revs = baseset(
-            dagop.toposort(revs, repo.changelog.parentrevs, firstbranch),
+            dagop.toposort(revs, parentsfunc, firstbranch),
             istopo=True,
         )
         if keyflags[0][1]: