What causes "cannot compile regexp %v for excludeTable: %v" in vitessio/vitess?

Correct the regexp in excludeTables; test it with a quick regexp.Compile check first

cannot compile regexp %v for excludeTable: %v

Error message

cannot compile regexp %v for excludeTable: %v

What it means

NewTableFilter treats entries in excludeTables that start with '/' as regular expressions; if such an entry fails regexp.Compile, this error is returned and the TableFilter is not created. Functionally identical to the tables variant, but for the exclusion list.

Source

Thrown at go/vt/mysqlctl/tmutils/schema.go:92

				if err != nil {
					return nil, fmt.Errorf("cannot compile regexp %v for table: %v", table, err)
				}

				f.tableREs = append(f.tableREs, re)
			} else {
				f.tableNames = append(f.tableNames, table)
			}
		}
	}

	if len(excludeTables) > 0 {
		f.filterExcludeTables = true
		for _, table := range excludeTables {
			if strings.HasPrefix(table, "/") {
				table = strings.Trim(table, "/")
				re, err := regexp.Compile(table)
				if err != nil {
					return nil, fmt.Errorf("cannot compile regexp %v for excludeTable: %v", table, err)
				}

				f.excludeTableREs = append(f.excludeTableREs, re)
			} else {
				f.excludeTableNames = append(f.excludeTableNames, table)
			}
		}
	}

	return f, nil
}

// Includes returns whether a tableName/tableType should be included in this TableFilter.
func (f *TableFilter) Includes(tableName string, tableType string) bool {
	if f.filterTables {
		matches := false
		for _, name := range f.tableNames {
			if strings.EqualFold(name, tableName) {

View on GitHub (pinned to 01a25a7d17)

Solutions

Correct the regexp in excludeTables; test it with a quick regexp.Compile check first
Escape regex metacharacters in literal table names
Drop the leading/trailing slashes if you intended an exact-name exclusion

Example fix

// before
tmutils.NewTableFilter(nil, []string{"/_test[/"}, false)
// after
tmutils.NewTableFilter(nil, []string{"/_test_.*"}, false)

Defensive patterns

Strategy: validation

Validate before calling

for _, t := range excludeTables {
    if strings.HasPrefix(t, "/") {
        if _, err := regexp.Compile(strings.Trim(t, "/")); err != nil {
            return fmt.Errorf("invalid excludeTable regexp %q: %v", t, err)
        }
    }
}

Type guard

func isRegexExcludeFilter(entry string) bool {
    return strings.HasPrefix(entry, "/")
}

Try / catch

f, err := tmutils.NewTableFilter(nil, excludeTables, false)
if err != nil {
    return vterrors.Wrapf(err, "invalid excludeTables configuration")
}

Prevention

Test exclusion regexps against the expected table list before use
Quote patterns properly in shell to avoid metacharacter mangling
Prefer exact names for simple exclusions and reserve /regex/ for real patterns
Add endtoend/config validation for exclude-table flags

When it happens

Trigger: Calling NewTableFilter (or higher-level GetSchema flows that pass excludeTables, e.g. vtctl schema commands) with an invalid /regex/ entry in the excludeTables slice.

Common situations: Malformed exclusion pattern like '/_(tmp$/'; unescaped metacharacters from copy-paste; shell quoting issues mangling the pattern before it reaches the API.

Related errors

AI-assisted analysis of vitessio/vitess@01a25a7d17 (2026-09-01). Data as JSON: /api/errors/2909b3d16d46189f. Report an issue: GitHub.