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

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.

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.

Appendix: 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) {

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