What causes "keyword %q must be lowercase in table" in vitessio/vitess?

Lowercase the keyword's name field in the keywords table

keyword %q must be lowercase in table

Error message

keyword %q must be lowercase in table

What it means

The init() in keywords.go validates that every keyword with a non-UNUSED id is stored lowercase, since keyword matching is done case-insensitively and keywordStrings/keywordVals maps assume canonical lowercase names. A non-lowercase keyword means lookups of the upper/mixed-case form would silently miss.

Source

Thrown at go/vt/sqlparser/keywords.go:877

	}
	return table
}

func (cit *caseInsensitiveTable) LookupString(name string) (int, bool) {
	hash := fnv1aIstr(offset64, name)
	if candidate, ok := cit.h[hash]; ok {
		return candidate.id, candidate.matchStr(name)
	}
	return 0, false
}

func init() {
	for _, kw := range keywords {
		if kw.id == UNUSED {
			continue
		}
		if kw.name != strings.ToLower(kw.name) {
			panic(fmt.Sprintf("keyword %q must be lowercase in table", kw.name))
		}
		keywordStrings[kw.id] = kw.name
		keywordVals[kw.name] = kw.id
	}

	keywordLookupTable = buildCaseInsensitiveTable(keywords)
}

// KeywordString returns the string corresponding to the given keyword
func KeywordString(id int) string {
	str, ok := keywordStrings[id]
	if !ok {
		return ""
	}
	return str
}

const (

View on GitHub (pinned to 01a25a7d17)

Solutions

Lowercase the keyword's name field in the keywords table
Ensure keywordVals map keys and keywordStrings values stay consistent by re-running go test ./go/vt/sqlparser

Example fix

// before
{id: GROUPREPLACE, name: "GroupReplace"}
// after
{id: GROUPREPLACE, name: "groupreplace"}

Defensive patterns

Strategy: validation

Validate before calling

for _, kw := range keywords {
    if kw.id != UNUSED && kw.name != strings.ToLower(kw.name) {
        return fmt.Errorf("keyword %q must be lowercase", kw.name)
    }
}

Prevention

Always author keyword names in lowercase and rely on case-insensitive lookup
Add a CI test asserting all keyword names are lowercase
Copy keyword names only from the existing lowercase table, not from docs

When it happens

Trigger: Adding a keyword entry like {id: SELECT, name: "Select"} or "SELECT" to the keywords slice; any edit introducing capital letters into kw.name.

Common situations: Copy-pasting keyword names from documentation or other SQL dialects (e.g. mixed-case T-SQL keywords) directly into the table.

Related errors

AI-assisted analysis of vitessio/vitess@01a25a7d17 (2026-09-01). Data as JSON: /api/errors/cd85206906e19b95. Report an issue: GitHub.