What causes "error reading contents: unmatched `END LOOP` keyword" in temporalio/temporal?

Locate the END LOOP in the schema file and ensure a matching LOOP appears earlier at the same nesting depth

error reading contents: unmatched `END LOOP` keyword

Error message

error reading contents: unmatched `END LOOP` keyword

What it means

During statement splitting, the parser maintains a stack of BEGIN/IF/LOOP blocks. Reaching `END LOOP` when the stack is empty or the top entry is not LOOP means the schema text has an END LOOP without a matching LOOP, so LoadAndSplitQueryFromReaders aborts with this error.

Source

Thrown at common/persistence/query_util.go:141

					if hasWordAt(contentStr, sqlBeginKeyword, j) {
						st = append(st, sqlBeginKeyword[0])
						j += len(sqlBeginKeyword) - 1
					}

				case sqlEndKeyword[0]:
					if !hasWordAt(contentStr, sqlEndKeyword, j) {
						continue
					}
					if ok, after := hasWordAfter(contentStr, sqlIfKeyword, j+len(sqlEndKeyword)); ok {
						if len(st) == 0 || st[len(st)-1] != sqlIfKeyword[0] {
							return nil, errors.New("error reading contents: unmatched `END IF` keyword")
						}
						st = st[:len(st)-1]
						j = after + len(sqlIfKeyword) - 1
					} else if ok, after := hasWordAfter(contentStr, sqlLoopKeyword, j+len(sqlEndKeyword)); ok {
						//nolint:revive
						if len(st) == 0 || st[len(st)-1] != sqlLoopKeyword[0] {
							return nil, errors.New("error reading contents: unmatched `END LOOP` keyword")
						}
						st = st[:len(st)-1]
						j = after + len(sqlLoopKeyword) - 1
					} else {
						if len(st) == 0 || st[len(st)-1] != sqlBeginKeyword[0] {
							return nil, errors.New("error reading contents: unmatched `END` keyword")
						}
						st = st[:len(st)-1]
						j += len(sqlEndKeyword) - 1
					}

				case sqlSingleQuote, sqlDoubleQuote:
					quote := contentStr[j]
					j++
					for j < n && contentStr[j] != quote {
						j++
					}
					if j == n {

View on GitHub (pinned to bde624efd1)

Solutions

Locate the END LOOP in the schema file and ensure a matching LOOP appears earlier at the same nesting depth
Restore the missing LOOP block or delete the stray END LOOP
Verify nesting order (BEGIN > IF/LOOP) is properly interleaved; reorder END statements so each END matches the innermost open block

Example fix

// before
BEGIN
  INSERT ...
END LOOP;
// after
BEGIN
  FOR r IN list LOOP
    INSERT ...;
  END LOOP;
END;

Defensive patterns

Strategy: validation

Validate before calling

depth := 0
for _, tok := range tokenizeUpper(content) {
    switch tok {
    case "LOOP":
        depth++
    case "END LOOP":
        depth--
        if depth < 0 {
            return errors.New("END LOOP without matching LOOP")
        }
    }
}

Prevention

Ensure each END LOOP is preceded by LOOP at the same nesting level
Close nested blocks in reverse order of opening (LIFO)
Run schema files through the splitter in CI to catch balance errors early

When it happens

Trigger: Calling LoadAndSplitQuery/LoadAndSplitQueryFromReaders on a schema file containing `END LOOP` whose corresponding `LOOP` was never opened (or was closed early/nested incorrectly).

Common situations: Copied CQL from another database dialect where LOOP syntax differs; a LOOP removed during editing leaving its END LOOP; nested BEGIN/LOOP pairs closed in the wrong order causing stack mismatch.

Related errors

AI-assisted analysis of temporalio/temporal@bde624efd1 (2026-09-01). Data as JSON: /api/errors/41814d31e266714a. Report an issue: GitHub.