Bug fixes for dolt_patch

go/libraries/doltcore/diff/diffsplitter.go

@@ -118,9 +118,6 @@ func mapQuerySchemaToTargetSchema(query, target sql.Schema) (mapping []int, err
 		} else {
 			return nil, errors.New("expected column prefix of 'to_' or 'from_' (" + col.Name + ")")
 		}
-		if mapping[i] < 0 { // sanity check
-			return nil, errors.New("failed to map diff column: " + col.Name)
-		}
 	}
 	return
 }
@@ -163,6 +160,10 @@ func (ds DiffSplitter) SplitDiffResultRow(row sql.Row) (from, to RowDiff, err er
 		from.RowDiff = Removed
 		for i := 0; i < ds.splitIdx; i++ {
 			j := ds.queryToTarget[i]
+			// skip any columns that aren't mapped
+			if j < 0 {
+				continue
+			}
 			from.Row[j] = row[i]
 			from.ColDiffs[j] = Removed
 		}
@@ -172,6 +173,10 @@ func (ds DiffSplitter) SplitDiffResultRow(row sql.Row) (from, to RowDiff, err er
 		to.RowDiff = Added
 		for i := ds.splitIdx; i < len(row); i++ {
 			j := ds.queryToTarget[i]
+			// skip any columns that aren't mapped
+			if j < 0 {
+				continue
+			}
 			to.Row[j] = row[i]
 			to.ColDiffs[j] = Added
 		}
@@ -181,6 +186,10 @@ func (ds DiffSplitter) SplitDiffResultRow(row sql.Row) (from, to RowDiff, err er
 		from.RowDiff = ModifiedOld
 		for i := 0; i < ds.splitIdx; i++ {
 			j := ds.queryToTarget[i]
+			// skip any columns that aren't mapped
+			if j < 0 {
+				continue
+			}
 			from.Row[j] = row[i]
 		}
 		to.Row = make(sql.Row, len(ds.targetSch))

go/libraries/doltcore/diff/table_deltas.go

@@ -601,6 +601,9 @@ func GetDataDiffStatement(tableName string, sch schema.Schema, row sql.Row, rowD
 				updatedCols.Add(sch.GetAllCols().GetByIndex(i).Name)
 			}
 		}
+		if updatedCols.Size() == 0 {
+			return "", nil
+		}
 		return sqlfmt.SqlRowAsUpdateStmt(row, tableName, sch, updatedCols)
 	case ModifiedOld:
 		// do nothing, we only issue UPDATE for ModifiedNew

go/libraries/doltcore/sqle/dolt_patch_table_function.go

@@ -424,16 +424,7 @@ func canGetDataDiff(ctx *sql.Context, td diff.TableDelta) bool {
 		})
 		return false
 	}
-	// cannot sql diff
-	if td.ToSch == nil || (td.FromSch != nil && !schema.SchemasAreEqual(td.FromSch, td.ToSch)) {
-		// TODO(8/24/22 Zach): this is overly broad, we can absolutely do better
-		ctx.Session.Warn(&sql.Warning{
-			Level:   "Warning",
-			Code:    mysql.ERNotSupportedYet,
-			Message: fmt.Sprintf("Incompatible schema change, skipping data diff for table '%s'", td.ToName),
-		})
-		return false
-	}
+
 	return true
 }
 
@@ -574,6 +565,13 @@ func GetNonCreateNonDropTableSqlSchemaDiff(td diff.TableDelta, toSchemas map[str
 		}
 	}
 
+	// Handle charset/collation changes
+	toCollation := toSch.GetCollation()
+	fromCollation := fromSch.GetCollation()
+	if toCollation != fromCollation {
+		ddlStatements = append(ddlStatements, sqlfmt.AlterTableCollateStmt(td.ToName, fromCollation, toCollation))
+	}
+
 	return ddlStatements, nil
 }