[PATCH stable] hg: use correct start / stop indices when slicing revisions

[Manuel Jacob]

# HG changeset patch
# User Manuel Jacob <me at manueljacob.de>
# Date 1645848272 -3600
#      Sat Feb 26 05:04:32 2022 +0100
# Branch stable
# Node ID 84c94153376698aa028c03dbad1fc0dcf6f081ed
# Parent  397f73d1cdd4b39c9c17bb8d45592e866fcab88c
hg: use correct start / stop indices when slicing revisions

Previously, the indices where determined on self.revisions, which contains all
visible revisions in the repository. However, in some cases, these indices were
used on a list which had the items at different positions.

With this change, the indices are always determined on the list which is sliced
with these indices.

I didn’t fully understand the comment that I moved. If it doesn’t make sense to
move it, I’d happy to send a new patch series removing or changing the comment
before or after this change.

diff --git a/kallithea/lib/vcs/backends/hg/repository.py b/kallithea/lib/vcs/backends/hg/repository.py
--- a/kallithea/lib/vcs/backends/hg/repository.py
+++ b/kallithea/lib/vcs/backends/hg/repository.py
@@ -525,20 +525,9 @@
         :param branch_name:
         :param reversed: return changesets in reversed order
         """
-        start_raw_id = self._get_revision(start)
-        start_pos = None if start is None else self.revisions.index(start_raw_id)
-        end_raw_id = self._get_revision(end)
-        end_pos = None if end is None else self.revisions.index(end_raw_id)
-
-        if start_pos is not None and end_pos is not None and start_pos > end_pos:
-            raise RepositoryError("Start revision '%s' cannot be "
-                                  "after end revision '%s'" % (start, end))
-
         if branch_name and branch_name not in self.allbranches:
             msg = "Branch %r not found in %s" % (branch_name, self.name)
             raise BranchDoesNotExistError(msg)
-        if end_pos is not None:
-            end_pos += 1
         # filter branches
         filter_ = []
         if branch_name:
@@ -554,13 +543,22 @@
                 revspec = b'all()'
             if max_revisions:
                 revspec = b'limit(%s, %d)' % (revspec, max_revisions)
-            revisions = mercurial.scmutil.revrange(self._repo, [revspec])
+            # this is very much a hack to turn this into a list; a better solution
+            # would be to get rid of this function entirely and use revsets
+            revisions = [self._get_revision(r) for r in mercurial.scmutil.revrange(self._repo, [revspec])]
         else:
             revisions = self.revisions
 
-        # this is very much a hack to turn this into a list; a better solution
-        # would be to get rid of this function entirely and use revsets
-        revs = list(revisions)[start_pos:end_pos]
+        start_raw_id = self._get_revision(start)
+        start_pos = None if start is None else revisions.index(start_raw_id)
+        end_raw_id = self._get_revision(end)
+        end_pos = None if end is None else revisions.index(end_raw_id)
+        if start_pos is not None and end_pos is not None and start_pos > end_pos:
+            raise RepositoryError("Start revision '%s' cannot be "
+                                  "after end revision '%s'" % (start, end))
+        if end_pos is not None:
+            end_pos += 1
+        revs = revisions[start_pos:end_pos]
         if reverse:
             revs.reverse()