refactor!: rename error vars to ErrFoo and expand lint enforcement (#11)

* refactor!: rename exported error vars from FooError to ErrFoo

BREAKING CHANGE: every exported error identifier changes name to match
the staticcheck ST1012 convention that the Go standard library uses.
Consumers referencing these variables must update their imports:

  NoBaseURLError             -> ErrNoBaseURL
  UnexpectedEmptyStringError -> ErrUnexpectedEmptyString
  NonEmptySuffixError        -> ErrNonEmptySuffix
  BadParserIndexError        -> ErrBadParserIndex
  DuplicatePartNameError     -> ErrDuplicatePartName
  RequiredTokenError         -> ErrRequiredToken
  InvalidIPv6HostnameError   -> ErrInvalidIPv6Hostname
  InvalidPortError           -> ErrInvalidPort
  EmptyPartNameError         -> ErrEmptyPartName
  InvalidModifierError       -> ErrInvalidModifier
  InvalidPrefixOrSuffix      -> ErrInvalidPrefixOrSuffix
  InvalidPartNameError       -> ErrInvalidPartName
  TypeError                  -> ErrType

Also drops the ST1012 exclusion from .golangci.yml since the codebase
now satisfies it.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* chore: address remaining golangci-lint findings and enforce them

Expand the enabled linter set in .golangci.yml (err113, goconst,
gocritic, intrange, modernize, perfsprint, thelper, unconvert, unparam,
wastedassign, whitespace) and address every new finding:

- wastedassign: collapse ExecInit's 8 dead var = "" initializations and
  one in parser.go where regexpValue was assigned and immediately
  reassigned.
- gocritic (assignOp / ifElseChain / typeSwitchVar): use x += y, rewrite
  if-else chains to switch, switch on typed values.
- intrange: for range b.N in benchmarks, for i := range len(portValue)
  in the port prefix check; keep escape.go as-is (i needed after loop)
  with a //nolint rationale.
- modernize: replace interface{} with any in tests, use slices.Contains.
- perfsprint: fmt.Sprintf("%d", i) -> strconv.Itoa(i) in test names.
- unconvert: drop redundant int() around p.componentStart.
- unparam: consumeRequiredToken no longer returns its *token since
  every caller discarded it.
- whitespace: trim a stray trailing newline in buildExpected and a
  leading one in newExpectedResult.
- err113: hoist "invalid hostname" to errInvalidHostname at package
  level, add two test-only sentinels for the WPT harness.
- goconst: extract "pattern"/"url" into initTypePattern / initTypeURL.
- thelper: t.Helper() in the three WPT test helpers.
- Drop the dead commented //p.result.Hash/Search lines in the
  constructor parser and refactor the surrounding if/else into a switch.

All 365 WPT cases + the regression tests still pass; golangci-lint
reports 0 issues with the widened configuration.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: dunglas

.golangci.yml

@@ -1,13 +1,22 @@
 version: "2"
 
 linters:
+  enable:
+    - err113
+    - goconst
+    - gocritic
+    - intrange
+    - modernize
+    - perfsprint
+    - thelper
+    - unconvert
+    - unparam
+    - wastedassign
+    - whitespace
   settings:
     staticcheck:
       checks:
         - "all"
-        # ST1012: public API exports FooError variables (NoBaseURLError,
-        # InvalidPortError, ...). Renaming to ErrFoo would break consumers.
-        - "-ST1012"
         # ST1020/ST1021: exported symbols are documented with their
         # corresponding WHATWG spec URL, not a "Foo does..." sentence.
         # The URL is the most useful pointer for maintainers of a

benchmark_test.go

@@ -40,7 +40,7 @@ func BenchmarkNew(b *testing.B) {
 			b.ReportAllocs()
 			var p *urlpattern.URLPattern
 			var err error
-			for i := 0; i < b.N; i++ {
+			for range b.N {
 				p, err = urlpattern.New(bc.pattern, bc.baseURL, nil)
 				if err != nil {
 					b.Fatal(err)
@@ -60,7 +60,7 @@ func BenchmarkTest(b *testing.B) {
 		b.Run(bc.name, func(b *testing.B) {
 			b.ReportAllocs()
 			var ok bool
-			for i := 0; i < b.N; i++ {
+			for range b.N {
 				ok = p.Test(bc.input, "")
 			}
 			benchBoolSink = ok
@@ -77,7 +77,7 @@ func BenchmarkExec(b *testing.B) {
 		b.Run(bc.name, func(b *testing.B) {
 			b.ReportAllocs()
 			var r *urlpattern.URLPatternResult
-			for i := 0; i < b.N; i++ {
+			for range b.N {
 				r = p.Exec(bc.input, "")
 			}
 			benchResultSink = r

constructor_type_parser.go

@@ -68,15 +68,13 @@ func parseConstructorString(input string) (*URLPatternInit, error) {
 			if p.state == stateInit {
 				p.rewind()
 
-				if p.isHashPrefix() {
+				switch {
+				case p.isHashPrefix():
 					p.changeState(stateHash, 1)
-				} else if p.isSearchPrefix() {
+				case p.isSearchPrefix():
 					p.changeState(stateSearch, 1)
-					//p.result.Hash = ""
-				} else {
+				default:
 					p.changeState(statePathname, 0)
-					//p.result.Hash = ""
-					//p.result.Search = ""
 				}
 
 				p.tokenIndex += p.tokenIncrement
@@ -160,26 +158,28 @@ func parseConstructorString(input string) (*URLPatternInit, error) {
 			}
 
 		case stateHostname:
-			if p.isIPV6Open() {
+			switch {
+			case p.isIPV6Open():
 				p.hostnameIPv6BracketDepth++
-			} else if p.isIPV6Close() {
+			case p.isIPV6Close():
 				p.hostnameIPv6BracketDepth--
-			} else if p.isPortPrefix() && p.hostnameIPv6BracketDepth == 0 {
+			case p.isPortPrefix() && p.hostnameIPv6BracketDepth == 0:
 				p.changeState(statePort, 1)
-			} else if p.isPathnameStart() {
+			case p.isPathnameStart():
 				p.changeState(statePathname, 0)
-			} else if p.isSearchPrefix() {
+			case p.isSearchPrefix():
 				p.changeState(stateSearch, 1)
-			} else if p.isHashPrefix() {
+			case p.isHashPrefix():
 				p.changeState(stateHash, 1)
 			}
 
 		case statePort:
-			if p.isPathnameStart() {
+			switch {
+			case p.isPathnameStart():
 				p.changeState(statePathname, 0)
-			} else if p.isSearchPrefix() {
+			case p.isSearchPrefix():
 				p.changeState(stateSearch, 1)
-			} else if p.isHashPrefix() {
+			case p.isHashPrefix():
 				p.changeState(stateHash, 1)
 			}
 
@@ -351,15 +351,15 @@ func (p *constructorTypeParser) changeState(newState state, skip int) {
 	}
 
 	p.state = newState
-	p.tokenIndex = p.tokenIndex + skip
+	p.tokenIndex += skip
 	p.componentStart = p.tokenIndex
 	p.tokenIncrement = 0
 }
 
 // https://urlpattern.spec.whatwg.org/#make-a-component-string
 func (p *constructorTypeParser) makeComponentString() string {
 	token := p.tokenList[p.tokenIndex]
-	componentStartToken := p.getSafeToken(int(p.componentStart))
+	componentStartToken := p.getSafeToken(p.componentStart)
 	componentStartInputIndex := componentStartToken.index
 	endIndex := token.index
 

escape.go

@@ -35,7 +35,7 @@ func init() {
 func escapeRegexpString(s string) string {
 	// A byte loop is correct because all metacharacters are ASCII.
 	var i int
-	for i = 0; i < len(s); i++ {
+	for i = 0; i < len(s); i++ { //nolint:intrange // i is reused below
 		if specialRegexp(s[i]) {
 			break
 		}
@@ -63,7 +63,7 @@ func escapeRegexpString(s string) string {
 func escapePatternString(s string) string {
 	// A byte loop is correct because all metacharacters are ASCII.
 	var i int
-	for i = 0; i < len(s); i++ {
+	for i = 0; i < len(s); i++ { //nolint:intrange // i is reused below
 		if specialPattern(s[i]) {
 			break
 		}

parser.go

@@ -39,14 +39,16 @@ var urlParser = url.NewParser()
 var hostnameParser = canonicalizer.New(canonicalizer.WithDefaultScheme("http"))
 
 var (
-	NonEmptySuffixError      = errors.New("suffix must be the empty string")
-	BadParserIndexError      = errors.New("parser's index must be less than parser's token list size")
-	DuplicatePartNameError   = errors.New("duplicate name")
-	RequiredTokenError       = errors.New("missing required token")
-	InvalidIPv6HostnameError = errors.New("invalid IPv6 hostname")
-	InvalidPortError         = errors.New("invalid port")
+	ErrNonEmptySuffix      = errors.New("suffix must be the empty string")
+	ErrBadParserIndex      = errors.New("parser's index must be less than parser's token list size")
+	ErrDuplicatePartName   = errors.New("duplicate name")
+	ErrRequiredToken       = errors.New("missing required token")
+	ErrInvalidIPv6Hostname = errors.New("invalid IPv6 hostname")
+	ErrInvalidPort         = errors.New("invalid port")
 )
 
+var errInvalidHostname = errors.New("invalid hostname")
+
 // https://urlpattern.spec.whatwg.org/#encoding-callback
 type encodingCallback func(string) (string, error)
 
@@ -88,7 +90,7 @@ func parsePatternString(input string, options options, encodingCallback encoding
 			}
 
 			if prefix != "" && prefix != string(options.prefixCodePoint) {
-				p.pendingFixedValue = p.pendingFixedValue + prefix
+				p.pendingFixedValue += prefix
 				prefix = ""
 			}
 
@@ -115,7 +117,7 @@ func parsePatternString(input string, options options, encodingCallback encoding
 			}
 		}
 		if fixedToken != nil {
-			p.pendingFixedValue = p.pendingFixedValue + fixedToken.value
+			p.pendingFixedValue += fixedToken.value
 
 			continue
 		}
@@ -146,7 +148,7 @@ func parsePatternString(input string, options options, encodingCallback encoding
 				return nil, err
 			}
 
-			if _, err := p.consumeRequiredToken(tokenClose); err != nil {
+			if err := p.consumeRequiredToken(tokenClose); err != nil {
 				return nil, fmt.Errorf("missing close token: %w", err)
 			}
 
@@ -166,7 +168,7 @@ func parsePatternString(input string, options options, encodingCallback encoding
 			return nil, err
 		}
 
-		if _, err := p.consumeRequiredToken(tokenEnd); err != nil {
+		if err := p.consumeRequiredToken(tokenEnd); err != nil {
 			return nil, fmt.Errorf("missing end token: %w", err)
 		}
 	}
@@ -189,7 +191,7 @@ type patternParser struct {
 func (p *patternParser) tryConsumeToken(tokenType tokenType) (*token, error) {
 	// Assert: parser’s index is less than parser’s token list size.
 	if p.index >= len(p.tokenList) {
-		return nil, BadParserIndexError
+		return nil, ErrBadParserIndex
 	}
 
 	nextToken := p.tokenList[p.index]
@@ -265,7 +267,7 @@ func (p *patternParser) addPart(prefix string, nameToken *token, regexpOrWildcar
 	}
 
 	if nameToken == nil && regexpOrWildcardToken == nil && modifier == partModifierNone {
-		p.pendingFixedValue = p.pendingFixedValue + prefix
+		p.pendingFixedValue += prefix
 
 		return nil
 	}
@@ -277,7 +279,7 @@ func (p *patternParser) addPart(prefix string, nameToken *token, regexpOrWildcar
 	if nameToken == nil && regexpOrWildcardToken == nil {
 		// Assert: suffix is the empty string.
 		if suffix != "" {
-			return NonEmptySuffixError
+			return ErrNonEmptySuffix
 		}
 
 		if prefix == "" {
@@ -295,12 +297,13 @@ func (p *patternParser) addPart(prefix string, nameToken *token, regexpOrWildcar
 		return nil
 	}
 
-	regexpValue := ""
-	if regexpOrWildcardToken == nil {
+	var regexpValue string
+	switch {
+	case regexpOrWildcardToken == nil:
 		regexpValue = p.segmentWildcardRegexp
-	} else if regexpOrWildcardToken.tType == tokenAsterisk {
+	case regexpOrWildcardToken.tType == tokenAsterisk:
 		regexpValue = fullWildcardRegexpValue
-	} else {
+	default:
 		regexpValue = regexpOrWildcardToken.value
 	}
 
@@ -312,7 +315,6 @@ func (p *patternParser) addPart(prefix string, nameToken *token, regexpOrWildcar
 	case fullWildcardRegexpValue:
 		pType = partFullWildcard
 		regexpValue = ""
-
 	}
 
 	name := ""
@@ -325,7 +327,7 @@ func (p *patternParser) addPart(prefix string, nameToken *token, regexpOrWildcar
 
 	// https://urlpattern.spec.whatwg.org/#is-a-duplicate-name
 	if _, seen := p.seenNames[name]; seen {
-		return DuplicatePartNameError
+		return ErrDuplicatePartName
 	}
 
 	encodedPrefix, err := p.encodingCallback(prefix)
@@ -373,16 +375,16 @@ func (p *patternParser) consumeText() (string, error) {
 }
 
 // https://urlpattern.spec.whatwg.org/#consume-a-required-token
-func (p *patternParser) consumeRequiredToken(tokenType tokenType) (*token, error) {
+func (p *patternParser) consumeRequiredToken(tokenType tokenType) error {
 	result, err := p.tryConsumeToken(tokenType)
 	if err != nil {
-		return nil, err
+		return err
 	}
 	if result == nil {
-		return nil, RequiredTokenError
+		return ErrRequiredToken
 	}
 
-	return result, nil
+	return nil
 }
 
 // https://urlpattern.spec.whatwg.org/#generate-a-segment-wildcard-regexp
@@ -435,7 +437,7 @@ func canonicalizeHostname(hostnameValue, protocolValue string) (string, error) {
 	if hostnameValue[0] != '[' {
 		for _, c := range hostnameValue {
 			if c == ':' {
-				return "", errors.New("invalid hostname")
+				return "", errInvalidHostname
 			}
 		}
 	}
@@ -478,16 +480,17 @@ func canonicalizePort(portValue, protocolValue string) (string, error) {
 	// an ASCII digit (e.g. "invalid80"). Without this the URL library returns
 	// an empty port instead of failing.
 	firstDigit := false
-	for i := 0; i < len(portValue); i++ {
+	for i := range len(portValue) {
 		c := portValue[i]
 		if c == '\t' || c == '\n' || c == '\r' {
 			continue
 		}
 		firstDigit = c >= '0' && c <= '9'
+
 		break
 	}
 	if !firstDigit {
-		return "", InvalidPortError
+		return "", ErrInvalidPort
 	}
 
 	scheme := protocolValue
@@ -595,7 +598,7 @@ func canonicalizeIPv6Hostname(value string) (string, error) {
 
 	for _, c := range value {
 		if c != '[' && c != ']' && c != ':' && !unicode.Is(unicode.ASCII_Hex_Digit, c) {
-			return "", InvalidIPv6HostnameError
+			return "", ErrInvalidIPv6Hostname
 		}
 
 		result.WriteRune(unicode.ToLower(c))

parts.go

@@ -20,10 +20,10 @@ const (
 )
 
 var (
-	EmptyPartNameError    = errors.New("part's name must not be empty string")
-	InvalidModifierError  = errors.New(`part's modifier must be "zero-or-more" or "one-or-more"`)
-	InvalidPrefixOrSuffix = errors.New("part's prefix is not the empty string or part's suffix is not the empty string")
-	InvalidPartNameError  = errors.New("part's name is not the empty string or null")
+	ErrEmptyPartName    = errors.New("part's name must not be empty string")
+	ErrInvalidModifier  = errors.New(`part's modifier must be "zero-or-more" or "one-or-more"`)
+	ErrInvalidPrefixOrSuffix = errors.New("part's prefix is not the empty string or part's suffix is not the empty string")
+	ErrInvalidPartName  = errors.New("part's name is not the empty string or null")
 )
 
 type partModifier uint8
@@ -81,7 +81,7 @@ func (pl partList) generateRegularExpressionAndNameList(options options) (string
 
 		// Assert: part's name is not the empty string.
 		if p.name == "" {
-			return "", nil, EmptyPartNameError
+			return "", nil, ErrEmptyPartName
 		}
 
 		nameList = append(nameList, p.name)
@@ -140,12 +140,12 @@ func (pl partList) generateRegularExpressionAndNameList(options options) (string
 
 		// Assert: part’s modifier is "zero-or-more" or "one-or-more".
 		if p.modifier != partModifierZeroOrMore && p.modifier != partModifierOneOrMore {
-			return "", nil, InvalidModifierError
+			return "", nil, ErrInvalidModifier
 		}
 
 		// Assert: part’s prefix is not the empty string or part’s suffix is not the empty string.
 		if p.prefix == "" && p.suffix == "" {
-			return "", nil, InvalidPrefixOrSuffix
+			return "", nil, ErrInvalidPrefixOrSuffix
 		}
 
 		result.WriteString("(?:")
@@ -233,7 +233,7 @@ func (pl partList) generatePatternString(options options) (string, error) {
 
 		// Assert: part’s name is not the empty string or null.
 		if part.name == "" {
-			return "", InvalidPartNameError
+			return "", ErrInvalidPartName
 		}
 
 		if needGrouping {

tokenizer.go

@@ -8,7 +8,7 @@ import (
 	"golang.org/x/exp/utf8string"
 )
 
-var TypeError = errors.New("type error")
+var ErrType = errors.New("type error")
 
 // https://wicg.github.io/urlpattern/#tokenizing
 type tokenizePolicy bool
@@ -241,7 +241,7 @@ func (t *tokenizer) addTokenWithDefaultPositionAndLength(tType tokenType) {
 
 func (t *tokenizer) processTokenizingError(nextPosition, valuePosition int) error {
 	if t.policy == tokenizePolicyStrict {
-		return fmt.Errorf("%w: %#v", TypeError, t)
+		return fmt.Errorf("%w: %#v", ErrType, t)
 	}
 
 	t.addTokenWithDefaultLength(tokenInvalidChar, nextPosition, valuePosition)