Fix handling of closing bracket as character

Sources/Glob/Pattern+Options.swift

@@ -22,8 +22,18 @@ public extension Pattern {
 		/// How wildcards are interpreted
 		public var wildcardBehavior: WildcardBehavior
 
-		/// When false, an error will be thrown if an empty range (`[]`) is found.
-		public var allowsEmptyRanges: Bool
+		/// How empty ranges (`[]`) are treated
+		public enum EmptyRangeBehavior: Sendable {
+			/// Treat an empty range as matching nothing, equivalent to nothing at all
+			case allow
+			/// Throw an error when an empty range is used
+			case error
+			/// When a range starts with a closing range character, treat the closing bracket as a character and continue the range
+			case treatClosingBracketAsCharacter
+		}
+
+		/// How are empty ranges handled.
+		public var emptyRangeBehavior: EmptyRangeBehavior
 
 		/// The character used to specify when a range matches characters that aren't in the range.
 		public var rangeNegationCharacter: Character = "!"
@@ -36,20 +46,20 @@ public extension Pattern {
 		/// Default options for parsing and matching patterns.
 		public static let `default`: Self = .init(
 			wildcardBehavior: .doubleStarMatchesFullPath,
-			allowsEmptyRanges: false
+			emptyRangeBehavior: .error
 		)
 
 		/// Attempts to match the behavior of [VSCode](https://code.visualstudio.com/docs/editor/glob-patterns).
 		public static let vscode: Self = Options(
 			wildcardBehavior: .doubleStarMatchesFullPath,
-			allowsEmptyRanges: false,
+			emptyRangeBehavior: .error,
 			rangeNegationCharacter: "^"
 		)
 
 		/// Attempts to match the behavior of [`filepath.Match` in go](https://pkg.go.dev/path/filepath#Match).
 		public static let go: Self = Options(
 			wildcardBehavior: .pathComponentsOnly,
-			allowsEmptyRanges: false,
+			emptyRangeBehavior: .error,
 			rangeNegationCharacter: "^"
 		)
 
@@ -58,7 +68,7 @@ public extension Pattern {
 		public static func posix() -> Self {
 			Options(
 				wildcardBehavior: .pathComponentsOnly,
-				allowsEmptyRanges: true
+				emptyRangeBehavior: .allow
 			)
 		}
 
@@ -68,7 +78,7 @@ public extension Pattern {
 		public static func fnmatch(usePathnameBehavior: Bool = false) -> Self {
 			Options(
 				wildcardBehavior: usePathnameBehavior ? .pathComponentsOnly : .singleStarMatchesFullPath,
-				allowsEmptyRanges: true
+				emptyRangeBehavior: .treatClosingBracketAsCharacter
 			)
 		}
 

Sources/Glob/Pattern.swift

@@ -102,6 +102,14 @@ public struct Pattern: Sendable {
 
 					var ranges: [ClosedRange<Character>] = []
 
+					if options.emptyRangeBehavior == .treatClosingBracketAsCharacter && pattern.first == "]" {
+						// https://man7.org/linux/man-pages/man7/glob.7.html
+						// The string enclosed by the brackets cannot be empty; therefore ']' can be allowed between the brackets, provided that it is the first character.
+
+						pattern = pattern.dropFirst()
+						ranges.append("]" ... "]")
+					}
+
 					while pattern.first != "]" {
 						guard pattern.first != "-" else { throw PatternParsingError.rangeMissingBounds }
 						guard let lower = try getNext() else { break }
@@ -126,10 +134,10 @@ public struct Pattern: Sendable {
 					pattern = pattern.dropFirst()
 
 					guard !ranges.isEmpty else {
-						if options.allowsEmptyRanges {
-							break
-						} else {
+						if options.emptyRangeBehavior == .error {
 							throw PatternParsingError.rangeIsEmpty
+						} else {
+							break
 						}
 					}
 

Tests/GlobTests/Pattern+fnmatchTests.swift

@@ -176,9 +176,7 @@ final class PatternFNMatchTests: XCTestCase {
 		// C		 "a"			"[][abc]"	       0
 		XCTAssertMatchesFNMatch("a", pattern: "[][abc]", flags: 0, result: 0)
 		// C		 "a]"			"[]a]]"		       0
-		XCTExpectFailure {
-			XCTAssertMatchesFNMatch("a]", pattern: "[]a]]", flags: 0, result: 0)
-		}
+		XCTAssertMatchesFNMatch("a]", pattern: "[]a]]", flags: 0, result: 0)
 	}
 
 	//  B.6 010(C)
@@ -194,17 +192,13 @@ final class PatternFNMatchTests: XCTestCase {
 	//  B.6 011(C)
 	func test_b_6_011_c() throws {
 		// C		 "]"			"[][abc]"	       0
-		XCTExpectFailure {
-			XCTAssertMatchesFNMatch("]", pattern: "[][abc]", flags: 0, result: 0)
-		}
+		XCTAssertMatchesFNMatch("]", pattern: "[][abc]", flags: 0, result: 0)
 		// C		 "abc]"			"[][abc]"	       NOMATCH
 		XCTAssertMatchesFNMatch("abc]", pattern: "[][abc]", flags: 0, result: NOMATCH)
 		// C		 "[]abc"		"[][]abc"	       NOMATCH
 		XCTAssertMatchesFNMatch("[]abc", pattern: "[][]abc", flags: 0, result: NOMATCH)
 		// C		 "]"			"[!]]"		       NOMATCH
-		XCTExpectFailure {
-			XCTAssertMatchesFNMatch("]", pattern: "[!]]", flags: 0, result: NOMATCH)
-		}
+		XCTAssertMatchesFNMatch("]", pattern: "[!]]", flags: 0, result: NOMATCH)
 		// C		 "aa]"			"[!]a]"		       NOMATCH
 		XCTAssertMatchesFNMatch("aa]", pattern: "[!]a]", flags: 0, result: NOMATCH)
 		// C		 "]"			"[!a]"		       0
@@ -991,9 +985,7 @@ final class PatternFNMatchTests: XCTestCase {
 		// C.UTF-8		 "a"			"[][abc]"	       0
 		XCTAssertMatchesFNMatch("a", pattern: "[][abc]", flags: 0, result: 0)
 		// C.UTF-8		 "a]"			"[]a]]"		       0
-		XCTExpectFailure {
-			XCTAssertMatchesFNMatch("a]", pattern: "[]a]]", flags: 0, result: 0)
-		}
+		XCTAssertMatchesFNMatch("a]", pattern: "[]a]]", flags: 0, result: 0)
 	}
 
 	//  B.6 010(C) utf8
@@ -1008,18 +1000,14 @@ final class PatternFNMatchTests: XCTestCase {
 
 	//  B.6 011(C) utf8
 	func test_b_6_011_c_utf8() throws {
-		XCTExpectFailure {
-			// C.UTF-8		 "]"			"[][abc]"	       0
-			XCTAssertMatchesFNMatch("]", pattern: "[][abc]", flags: 0, result: 0)
-		}
+		// C.UTF-8		 "]"			"[][abc]"	       0
+		XCTAssertMatchesFNMatch("]", pattern: "[][abc]", flags: 0, result: 0)
 		// C.UTF-8		 "abc]"			"[][abc]"	       NOMATCH
 		XCTAssertMatchesFNMatch("abc]", pattern: "[][abc]", flags: 0, result: NOMATCH)
 		// C.UTF-8		 "[]abc"		"[][]abc"	       NOMATCH
 		XCTAssertMatchesFNMatch("[]abc", pattern: "[][]abc", flags: 0, result: NOMATCH)
-		XCTExpectFailure {
-			// C.UTF-8		 "]"			"[!]]"		       NOMATCH
-			XCTAssertMatchesFNMatch("]", pattern: "[!]]", flags: 0, result: NOMATCH)
-		}
+		// C.UTF-8		 "]"			"[!]]"		       NOMATCH
+		XCTAssertMatchesFNMatch("]", pattern: "[!]]", flags: 0, result: NOMATCH)
 		// C.UTF-8		 "aa]"			"[!]a]"		       NOMATCH
 		XCTAssertMatchesFNMatch("aa]", pattern: "[!]a]", flags: 0, result: NOMATCH)
 		// C.UTF-8		 "]"			"[!a]"		       0