[Bugfix] Copy snak IDs/hashes when using editEntity

Previously, any new claims added manually to the item via direct access
to `item.claims` would keep on getting added again every time editEntity
was called. By assigning the snak IDs/hashes that are created
when a new claim/qualifier/reference is created,
duplicates should not occur.

Note: To allow flake8 to pass, I had to reduce the names of variables.
The original names can be found as a comment on the patchset.

Bug: T327607
Change-Id: I26d043702d7cef63afcfc103ce7206ca9c8e5c41
---
M pywikibot/page/_wikibase.py
M tests/wikibase_edit_tests.py
2 files changed, 75 insertions(+), 0 deletions(-)

diff --git a/pywikibot/page/_wikibase.py b/pywikibot/page/_wikibase.py
index 405af2b..ca4e2f1 100644
--- a/pywikibot/page/_wikibase.py
+++ b/pywikibot/page/_wikibase.py
@@ -299,8 +299,12 @@
 
         :param data: Data to be saved
         """
+        update_self = False
         if data is None:
             data = self.toJSON(diffto=getattr(self, '_content', None))
+            # We only want to copy the IDs from the updates
+            # if data was not passed in.
+            update_self = True
         else:
             data = self._normalizeData(data)
 
@@ -321,6 +325,27 @@
         if hasattr(self, '_content'):
             del self._content
         self.latest_revision_id = updates['entity'].get('lastrevid')
+        if update_self and 'claims' in updates['entity']:
+            updated_claims = updates['entity']['claims']
+            for claim_prop_id, statements in updated_claims.items():
+                for claim_index, statement in enumerate(statements):
+                    claim = self.claims[claim_prop_id][claim_index]
+                    claim.snak = statement['id']
+                    claim.on_item = self
+                    updated_qualifiers = statement.get('qualifiers', {})
+                    for qual_propid, qualifier in updated_qualifiers.items():
+                        for qual_index, qual_statement in enumerate(qualifier):
+                            target_qual_prop = claim.qualifiers[qual_propid]
+                            target_qual = target_qual_prop[qual_index]
+                            target_qual.hash = qual_statement['hash']
+                    updated_references = statement.get('references', [])
+                    for ref_grp_idx, ref_grp in enumerate(updated_references):
+                        for ref_propid, reference in ref_grp['snaks'].items():
+                            for ref_index, ref_stat in enumerate(reference):
+                                target_ref_grp = claim.references[ref_grp_idx]
+                                target_ref_prop = target_ref_grp[ref_propid]
+                                target_ref = target_ref_prop[ref_index]
+                                target_ref.hash = ref_stat['hash']
 
     def concept_uri(self) -> str:
         """
diff --git a/tests/wikibase_edit_tests.py b/tests/wikibase_edit_tests.py
index 0de943f..c0892cf 100755
--- a/tests/wikibase_edit_tests.py
+++ b/tests/wikibase_edit_tests.py
@@ -127,6 +127,37 @@
         item = pywikibot.ItemPage(testsite)
         item.editEntity(data)
 
+    def test_edit_entity_propogation(self):
+        """Test that ``ItemPage.editEntity`` propagates changes to claims."""
+        testsite = self.get_repo()
+        item = pywikibot.ItemPage(testsite)
+        claim = pywikibot.Claim(testsite, 'P97339')
+        claim.setTarget('test')
+        qual = pywikibot.Claim(testsite, 'P97339')
+        qual.setTarget('test')
+        ref = pywikibot.Claim(testsite, 'P97339')
+        ref.setTarget('test')
+        claim.addQualifier(qual)
+        claim.addSource(ref)
+        item.editEntity()
+        self.assertIsNotNone(claim.snak)
+        self.assertIsNotNone(qual.hash)
+        self.assertIsNotNone(ref.hash)
+        self.assertSame(claim.on_item, item)
+        self.assertSame(qual.on_item, item)
+        self.assertSame(ref.on_item, item)
+        qual = pywikibot.Claim(testsite, 'P97339')
+        qual.setTarget('test')
+        ref = pywikibot.Claim(testsite, 'P97339')
+        ref.setTarget('test')
+        claim.qualifiers[qual.id].append(qual)
+        claim.sources[0][ref.id].append(ref)
+        item.editEntity()
+        self.assertIsNotNone(qual.hash)
+        self.assertIsNotNone(ref.hash)
+        self.assertSame(qual.on_item, item)
+        self.assertSame(ref.on_item, item)
+
     def test_edit_entity_new_property(self):
         """Test creating a new property using ``PropertyPage.editEntity``."""
         testsite = self.get_repo()

