delta-find: move pre-filtering with other pre-filtering logic

This is more consistent and will help use to be in a clean state before dealing
with the "too large group" issue.

As a side effect, the debug output now skip some useless cases, making it more useful.

mercurial/revlogutils/deltas.py

@@ -661,6 +661,8 b' def _candidategroups('
     p1,
     p2,
     cachedelta,
+    excluded_bases=None,
+    target_rev=None,
 ):
     """Provides group of revision to be tested as delta base
 
@@ -706,6 +708,13 b' def _candidategroups('
             if rev in tested:
                 continue
             tested.add(rev)
+            # an higher authority deamed the base unworthy (e.g. censored)
+            if excluded_bases is not None and rev in excluded_bases:
+                continue
+            # We are in some recomputation cases and that rev is too high in
+            # the revlog
+            if target_rev is not None and rev >= target_rev:
+                continue
             # filter out delta base that will never produce good delta
             if deltas_limit < revlog.length(rev):
                 continue
@@ -1180,6 +1189,8 b' class deltacomputer:'
             p1r,
             p2r,
             cachedelta,
+            excluded_bases,
+            target_rev,
         )
         candidaterevs = next(groups)
         while candidaterevs is not None:
@@ -1243,16 +1254,7 b' class deltacomputer:'
                     msg = b"DBG-DELTAS-SEARCH:     base=%d\n"
                     msg %= self.revlog.deltaparent(candidaterev)
                     self._write_debug(msg)
-                if candidaterev in excluded_bases:
-                    if debug_search:
-                        msg = b"DBG-DELTAS-SEARCH:     EXCLUDED\n"
-                        self._write_debug(msg)
-                    continue
-                if candidaterev >= target_rev:
-                    if debug_search:
-                        msg = b"DBG-DELTAS-SEARCH:     TOO-HIGH\n"
-                        self._write_debug(msg)
-                    continue
+
                 dbg_try_count += 1
 
                 if debug_search:

tests/test-sparse-revlog.t

@@ -159,7 +159,7 b' Test `debug-delta-find`'
      4971    4970      -1       3        5     4930    snap      19179     346472     427596   1.23414  15994877  15567281   36.40652     427596     179288   1.00000        5
   $ hg debug-delta-find SPARSE-REVLOG-TEST-FILE 4971
   DBG-DELTAS-SEARCH: SEARCH rev=4971
-  DBG-DELTAS-SEARCH: ROUND #1 - 2 candidates - search-down
+  DBG-DELTAS-SEARCH: ROUND #1 - 1 candidates - search-down
   DBG-DELTAS-SEARCH:   CANDIDATE: rev=4962
   DBG-DELTAS-SEARCH:     type=snapshot-4
   DBG-DELTAS-SEARCH:     size=18296
@@ -167,11 +167,6 b' Test `debug-delta-find`'
   DBG-DELTAS-SEARCH:     uncompressed-delta-size=30377
   DBG-DELTAS-SEARCH:     delta-search-time=* (glob)
   DBG-DELTAS-SEARCH:     DELTA: length=16872 (BAD)
-  DBG-DELTAS-SEARCH:   CANDIDATE: rev=4971
-  DBG-DELTAS-SEARCH:     type=snapshot-4
-  DBG-DELTAS-SEARCH:     size=19179
-  DBG-DELTAS-SEARCH:     base=4930
-  DBG-DELTAS-SEARCH:     TOO-HIGH
   DBG-DELTAS-SEARCH: ROUND #2 - 1 candidates - search-down
   DBG-DELTAS-SEARCH:   CANDIDATE: rev=4930
   DBG-DELTAS-SEARCH:     type=snapshot-3