D7657: rust-index: handle `MixedIndex` in `pyindex_to_graph`

[marmoute (Pierre-Yves David)]

marmoute created this revision.
Herald added subscribers: mercurial-devel, kevincox, durin42.
Herald added a reviewer: hg-reviewers.

REVISION SUMMARY
  On the long run we will want to implement the Graph trait directly in Rust, but
  for now we take the path with the least amount of change to focus on the coming
  persistent NodeMap code.
  
  We test this new code through with the lazy ancestors code.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D7657

AFFECTED FILES
  rust/hg-cpython/src/revlog.rs
  tests/test-rust-revlog.py

CHANGE DETAILS

diff --git a/tests/test-rust-revlog.py b/tests/test-rust-revlog.py
--- a/tests/test-rust-revlog.py
+++ b/tests/test-rust-revlog.py
@@ -10,6 +10,9 @@
 else:
     from mercurial.rustext import revlog
 
+    # this would fail already without appropriate ancestor.__package__
+    from mercurial.rustext.ancestor import LazyAncestors
+
 from mercurial.testing import revlog as revlogtesting
 
 
@@ -27,6 +30,22 @@
         rustidx = revlog.MixedIndex(idx)
         self.assertEqual(len(rustidx), len(idx))
 
+    def test_ancestors(self):
+        idx = self.parseindex()
+        rustidx = revlog.MixedIndex(idx)
+        lazy = LazyAncestors(rustidx, [3], 0, True)
+        # we have two more references to the index:
+        # - in its inner iterator for __contains__ and __bool__
+        # - in the LazyAncestors instance itself (to spawn new iterators)
+        self.assertTrue(2 in lazy)
+        self.assertTrue(bool(lazy))
+        self.assertEqual(list(lazy), [3, 2, 1, 0])
+        # a second time to validate that we spawn new iterators
+        self.assertEqual(list(lazy), [3, 2, 1, 0])
+
+        # let's check bool for an empty one
+        self.assertFalse(LazyAncestors(idx, [0], 0, False))
+
 
 if __name__ == '__main__':
     import silenttestrunner
diff --git a/rust/hg-cpython/src/revlog.rs b/rust/hg-cpython/src/revlog.rs
--- a/rust/hg-cpython/src/revlog.rs
+++ b/rust/hg-cpython/src/revlog.rs
@@ -15,7 +15,10 @@
 
 /// Return a Struct implementing the Graph trait
 pub(crate) fn pyindex_to_graph(py: Python, index: PyObject) -> PyResult<cindex::Index> {
-    cindex::Index::new(py, index)
+    match index.extract::<MixedIndex>(py) {
+        Ok(midx) => Ok(midx.clone_cindex(py)),
+        Err(_) => cindex::Index::new(py, index),
+    }
 }
 
 py_class!(pub class MixedIndex |py| {



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Cc: durin42, kevincox, mercurial-devel