internal/postgres: truncate raw_latest_versions

For golang/go#43265
For golang/go#41321

Change-Id: I7bf803b68b1532b968ad1175433275f5a4778078
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/296812
Trust: Jonathan Amsterdam <[email protected]>
Run-TryBot: Jonathan Amsterdam <[email protected]>
TryBot-Result: kokoro <[email protected]>
Reviewed-by: Julie Qiu <[email protected]>

Author: jba

internal/postgres/test_helper.go

@@ -113,7 +113,8 @@ func ResetTestDB(db *DB, t *testing.T) {
 			TRUNCATE version_map;
 			TRUNCATE paths CASCADE;
 			TRUNCATE symbol_names CASCADE;
-			TRUNCATE imports_unique;`); err != nil {
+			TRUNCATE imports_unique;
+			TRUNCATE raw_latest_versions;`); err != nil {
 			return err
 		}
 		if _, err := tx.Exec(ctx, `TRUNCATE module_version_states CASCADE;`); err != nil {

internal/postgres/version.go

@@ -320,6 +320,7 @@ func (db *DB) UpdateRawLatestInfo(ctx context.Context, info *internal.RawLatestI
 			}
 		}
 
+		log.Debugf(ctx, "updating raw latest from %q to %q", curVersion, info.Version)
 		return upsertRawLatestInfo(ctx, tx, id, info)
 	})
 }