Fix Mercurial 7.2 API compatibility for cmdutil.findpossible

The cmdutil.findpossible function was removed in Mercurial 7.2.
Instead of introspecting the command table to get diff defaults,
use mdiff.diffopts.defaults directly which is more stable.

Author: mvdbeek

lib/tool_shed/webapp/controllers/repository.py

@@ -6,8 +6,6 @@
 from datetime import date
 
 from mercurial import (
-    cmdutil,
-    commands,
     mdiff,
     patch,
 )
@@ -75,14 +73,14 @@
 
 
 def get_mercurial_default_options_dict(command):
-    """Borrowed from repoman - get default parameters for a mercurial command."""
-    possible = cmdutil.findpossible(command, commands.table)
-    # Mercurial >= 3.4 returns a tuple whose first element is the old return dict
-    if type(possible) is tuple:
-        possible = possible[0]
-    if len(possible) != 1:
-        raise Exception(f'unable to find mercurial command "{command}"')
-    return {r[1].replace(b"-", b"_"): r[2] for r in next(iter(possible.values()))[1][1]}
+    """Get default parameters for a mercurial command."""
+    # Use mdiff.diffopts defaults directly instead of introspecting command table
+    # (the old cmdutil.findpossible API was removed in Mercurial 7.2)
+    if command == b"diff":
+        # Convert byte keys to strings but preserve value types (int, bool)
+        # as mdiff.diffopts expects properly typed values
+        return {(k.decode("utf-8") if isinstance(k, bytes) else k): v for k, v in mdiff.diffopts.defaults.items()}
+    raise Exception(f'unable to find mercurial command "{command}"')
 
 
 class RepositoryController(BaseUIController, ratings_util.ItemRatings):
@@ -2366,10 +2364,8 @@ def view_changeset(self, trans, id, ctx_str, **kwd):
         else:
             ctx_child = None
         diffs = []
+        # Get default diff options with string keys and properly typed values
         options_dict = get_mercurial_default_options_dict(b"diff")
-        # Not quite sure if the following settings make any difference, but with a combination of them and the size check on each
-        # diff, we don't run out of memory when viewing the changelog of the cisortho2 repository on the test tool shed.
-        options_dict = {util.unicodify(k): util.unicodify(v) for k, v in options_dict.items()}
         options_dict["maxfile"] = basic_util.MAXDIFFSIZE
         options_dict["maxtotal"] = basic_util.MAXDIFFSIZE
         diffopts = mdiff.diffopts(**options_dict)