Escape backslash and square brackets in addition to single quotes (#222)

* Escape backslash and square brackets as well as single quotes (#218 and #221)

- Escape appropriate chars in subcommand abstracts as well.

* Add test for escaped zsh characters

Author: Wevah

Sources/ArgumentParser/Completions/ZshCompletionsGenerator.swift

@@ -50,7 +50,7 @@ struct ZshCompletionsGenerator {
 
       let subcommandModes = subcommands.map {
         """
-        '\($0._commandName):\($0.configuration.abstract)'
+        '\($0._commandName):\($0.configuration.abstract.zshEscaped())'
         """
         .indentingEachLine(by: 12)
       }
@@ -112,8 +112,15 @@ struct ZshCompletionsGenerator {
 
 extension String {
   fileprivate func zshEscapingSingleQuotes() -> String {
-    self.split(separator: "'", omittingEmptySubsequences: false)
-      .joined(separator: #"'"'"'"#)
+    self.replacingOccurrences(of: "'", with: #"'"'"'"#)
+  }
+
+  fileprivate func zshEscapingMetacharacters() -> String {
+    self.replacingOccurrences(of: #"[\\\[\]]"#, with: #"\\$0"#, options: .regularExpression)
+  }
+
+  fileprivate func zshEscaped() -> String {
+    self.zshEscapingSingleQuotes().zshEscapingMetacharacters()
   }
 }
 
@@ -123,7 +130,7 @@ extension ArgumentDefinition {
         let abstract = help.help?.abstract,
         !abstract.isEmpty
         else { return "" }
-    return "[\(abstract.zshEscapingSingleQuotes())]"
+    return "[\(abstract.zshEscaped())]"
   }
 
   func zshCompletionString(_ commands: [ParsableCommand.Type]) -> String? {
@@ -165,7 +172,7 @@ extension ArgumentDefinition {
       let pattern = extensions.isEmpty
         ? ""
         : " -g '\(extensions.map { "*." + $0 }.joined(separator: " "))'"
-      return "_files\(pattern.zshEscapingSingleQuotes())"
+      return "_files\(pattern.zshEscaped())"
 
     case .directory:
       return "_files -/"

Tests/ArgumentParserUnitTests/CompletionScriptTests.swift

@@ -109,6 +109,26 @@ extension CompletionScriptTests {
   }
 }
 
+extension CompletionScriptTests {
+  struct Escaped: ParsableCommand {
+    @Option(help: #"Escaped chars: '[]\."#)
+    var one: String
+  }
+
+  func testEscaped_Zsh() throws {
+    let script1 = try CompletionsGenerator(command: Escaped.self, shell: .zsh)
+          .generateCompletionScript()
+    XCTAssertEqual(zshEscapedCompletion, script1)
+
+    let script2 = try CompletionsGenerator(command: Escaped.self, shellName: "zsh")
+          .generateCompletionScript()
+    XCTAssertEqual(zshEscapedCompletion, script2)
+
+    let script3 = Escaped.completionScript(for: .zsh)
+    XCTAssertEqual(zshEscapedCompletion, script3)
+  }
+}
+
 private let zshBaseCompletions = """
 #compdef base
 local context state state_descr line
@@ -185,3 +205,32 @@ _base() {
 
 complete -F _base base
 """
+
+private let zshEscapedCompletion = """
+#compdef escaped
+local context state state_descr line
+_escaped_commandname=$words[1]
+typeset -A opt_args
+
+_escaped() {
+    integer ret=1
+    local -a args
+    args+=(
+        '--one[Escaped chars: '"'"'\\[\\]\\\\.]:one:'
+        '(-h --help)'{-h,--help}'[Print help information.]'
+    )
+    _arguments -w -s -S $args[@] && ret=0
+
+    return ret
+}
+
+
+_custom_completion() {
+    local completions=($($*))
+    _describe '' completions
+}
+
+_escaped
+"""
+
+