(core) Fix error when updating summary table formulas after rename

Summary:
Formulas in summary tables were being associated with the source table for automatic updating. When a table/column was renamed such that the formula needed to update to match, it would look for a column with the same colId but in the source table. Such a column might not exist which would lead to an error, or if it existed then the update would be wrong.

This association was created while building formulas to display in the code view in a nested `_Summary` class, it didn't need to exist at all. So this diff simply prevents the association from being created.

User report and discussion: https://grist.slack.com/archives/C0234CPPXPA/p1659717322297019

Test Plan: Extended `TestSummary.test_table_rename` Python test.

Reviewers: georgegevoian

Reviewed By: georgegevoian

Differential Revision: https://phab.getgrist.com/D3568

sandbox/grist/codebuilder.py

@@ -350,7 +350,8 @@ def parse_grist_names(builder):
     if not patch_source:
       return None
     in_text, in_value, in_patch = patch_source
-    return (in_value, in_patch.start, table_id, col_id)
+    if in_value:
+      return (in_value, in_patch.start, table_id, col_id)
 
   parsed_names = []
   for node in asttokens.util.walk(atok.tree):

sandbox/grist/gencode.py

@@ -92,7 +92,10 @@ class GenCode(object):
     body = self._formula_cache.get(key)
     if body is None:
       default = get_type_default(col_info.type)
-      body = codebuilder.make_formula_body(col_info.formula, default, (table_id, col_info.colId))
+      # If we have a table_id like `Table._Summary`, then we don't want to actually associate
+      # this field with any real table/column.
+      assoc_value = None if table_id.endswith("._Summary") else (table_id, col_info.colId)
+      body = codebuilder.make_formula_body(col_info.formula, default, assoc_value)
     self._new_formula_cache[key] = body
 
     decorator = ''
@@ -147,7 +150,12 @@ class GenCode(object):
                              for c in six.itervalues(s.columns) if c.isFormula)
       parts.append(indent(textbuilder.Text("\nclass _Summary:\n")))
       for col_info in six.itervalues(formulas):
-        parts.append(indent(self._make_field(col_info, table_id), levels=2))
+        # Associate this field with the fake table `table_id + "._Summary"`.
+        # We don't know which summary table each formula belongs to, there might be several,
+        # and we don't care here because this is just for display in the code view.
+        # The real formula will be associated with the real summary table elsewhere.
+        # Previously this field was accidentally associated with the source table, causing bugs.
+        parts.append(indent(self._make_field(col_info, table_id + "._Summary"), levels=2))
 
     return textbuilder.Combiner(parts)
 

sandbox/grist/test_summary.py

@@ -529,6 +529,13 @@ class Address:
       [2, "Address_summary_city_state",   1],
     ])
 
+    # Add a column to the summary table with a name that doesn't exist in the source table,
+    # to test a specific bug fix.
+    self.add_column(
+      "Address_summary_city_state", "lookup",
+      formula="Address.lookupRecords(city=$city)", isFormula=True
+    )
+
     # Rename the table: this is what we are really testing in this test case.
     self.apply_user_action(["RenameTable", "Address", "Location"])
 
@@ -537,6 +544,14 @@ class Address:
       [2, "Location_summary_city_state",   1],
     ])
 
+    # Check that the summary table column's formula was updated correctly.
+    self.assertTableData("_grist_Tables_column", cols="subset", rows="subset", data=[
+      ["id", "colId", "formula"],
+      [19, "lookup", "Location.lookupRecords(city=$city)"],
+    ])
+    # This column isn't expected in _do_test_updates().
+    self.remove_column("Location_summary_city_state", "lookup")
+
     # Verify that the bigger summary table respects all updates to the renamed source table.
     self._do_test_updates("Location", "Location_summary_city_state")