precondition => require

Author: Maxim Moiseev

Diff for: stdlib/private/StdlibUnittestFoundationExtras/StdlibUnittestFoundationExtras.swift

@@ -28,13 +28,13 @@ public func withOverriddenNSLocaleCurrentLocale<Result>(
 ) -> Result {
   let oldMethod = class_getClassMethod(
     NSLocale.self, Selector("currentLocale"))
-  precondition(oldMethod != nil, "could not find +[NSLocale currentLocale]")
+  require(oldMethod != nil, "could not find +[NSLocale currentLocale]")
 
   let newMethod = class_getClassMethod(
     NSLocale.self, Selector("_swiftUnittest_currentLocale"))
-  precondition(newMethod != nil, "could not find +[NSLocale _swiftUnittest_currentLocale]")
+  require(newMethod != nil, "could not find +[NSLocale _swiftUnittest_currentLocale]")
 
-  precondition(_temporaryNSLocaleCurrentLocale == nil,
+  require(_temporaryNSLocaleCurrentLocale == nil,
     "nested calls to withOverriddenNSLocaleCurrentLocale are not supported")
 
   _temporaryNSLocaleCurrentLocale = temporaryLocale
@@ -50,7 +50,7 @@ public func withOverriddenNSLocaleCurrentLocale<Result>(
   temporaryLocaleIdentifier: String,
   @noescape _ body: () -> Result
 ) -> Result {
-  precondition(
+  require(
     NSLocale.availableLocaleIdentifiers().contains(temporaryLocaleIdentifier),
     "requested locale \(temporaryLocaleIdentifier) is not available")
 

Diff for: stdlib/private/SwiftPrivateDarwinExtras/Subprocess.swift

@@ -54,7 +54,7 @@ func posixPipe() -> (readFD: CInt, writeFD: CInt) {
     (fds) in
     let ptr = fds.baseAddress
     if pipe(ptr) != 0 {
-      preconditionFailure("pipe() failed")
+      requirementFailure("pipe() failed")
     }
   }
   return (fds[0], fds[1])
@@ -66,46 +66,46 @@ public func spawnChild(args: [String])
   -> (pid: pid_t, stdinFD: CInt, stdoutFD: CInt, stderrFD: CInt) {
   var fileActions: posix_spawn_file_actions_t = nil
   if swift_posix_spawn_file_actions_init(&fileActions) != 0 {
-    preconditionFailure("swift_posix_spawn_file_actions_init() failed")
+    requirementFailure("swift_posix_spawn_file_actions_init() failed")
   }
 
   let childStdin = posixPipe()
   // Close the write end of the pipe on the child side.
   if swift_posix_spawn_file_actions_addclose(
     &fileActions, childStdin.writeFD) != 0 {
-    preconditionFailure("swift_posix_spawn_file_actions_addclose() failed")
+    requirementFailure("swift_posix_spawn_file_actions_addclose() failed")
   }
 
   // Remap child's stdin.
   if swift_posix_spawn_file_actions_adddup2(
     &fileActions, childStdin.readFD, STDIN_FILENO) != 0 {
-    preconditionFailure("swift_posix_spawn_file_actions_adddup2() failed")
+    requirementFailure("swift_posix_spawn_file_actions_adddup2() failed")
   }
 
   let childStdout = posixPipe()
   // Close the read end of the pipe on the child side.
   if swift_posix_spawn_file_actions_addclose(
     &fileActions, childStdout.readFD) != 0 {
-    preconditionFailure("swift_posix_spawn_file_actions_addclose() failed")
+    requirementFailure("swift_posix_spawn_file_actions_addclose() failed")
   }
 
   // Remap child's stdout.
   if swift_posix_spawn_file_actions_adddup2(
     &fileActions, childStdout.writeFD, STDOUT_FILENO) != 0 {
-    preconditionFailure("swift_posix_spawn_file_actions_adddup2() failed")
+    requirementFailure("swift_posix_spawn_file_actions_adddup2() failed")
   }
 
   let childStderr = posixPipe()
   // Close the read end of the pipe on the child side.
   if swift_posix_spawn_file_actions_addclose(
     &fileActions, childStderr.readFD) != 0 {
-    preconditionFailure("swift_posix_spawn_file_actions_addclose() failed")
+    requirementFailure("swift_posix_spawn_file_actions_addclose() failed")
   }
 
   // Remap child's stderr.
   if swift_posix_spawn_file_actions_adddup2(
     &fileActions, childStderr.writeFD, STDERR_FILENO) != 0 {
-    preconditionFailure("swift_posix_spawn_file_actions_adddup2() failed")
+    requirementFailure("swift_posix_spawn_file_actions_adddup2() failed")
   }
 
   var pid: pid_t = -1
@@ -115,26 +115,26 @@ public func spawnChild(args: [String])
   }
   if spawnResult != 0 {
     print(String.fromCString(strerror(spawnResult)))
-    preconditionFailure("swift_posix_spawn() failed")
+    requirementFailure("swift_posix_spawn() failed")
   }
 
   if swift_posix_spawn_file_actions_destroy(&fileActions) != 0 {
-    preconditionFailure("swift_posix_spawn_file_actions_destroy() failed")
+    requirementFailure("swift_posix_spawn_file_actions_destroy() failed")
   }
 
   // Close the read end of the pipe on the parent side.
   if close(childStdin.readFD) != 0 {
-    preconditionFailure("close() failed")
+    requirementFailure("close() failed")
   }
 
   // Close the write end of the pipe on the parent side.
   if close(childStdout.writeFD) != 0 {
-    preconditionFailure("close() failed")
+    requirementFailure("close() failed")
   }
 
   // Close the write end of the pipe on the parent side.
   if close(childStderr.writeFD) != 0 {
-    preconditionFailure("close() failed")
+    requirementFailure("close() failed")
   }
 
   return (pid, childStdin.writeFD, childStdout.readFD, childStderr.readFD)
@@ -156,7 +156,7 @@ internal func _readAll(fd: CInt) -> String {
     if readResult == 0 {
       break
     }
-    preconditionFailure("read() failed")
+    requirementFailure("read() failed")
   }
   return String._fromCodeUnitSequenceWithRepair(
     UTF8.self, input: buffer[0..<usedBytes]).0
@@ -193,15 +193,15 @@ public enum ProcessTerminationStatus : CustomStringConvertible {
 public func posixWaitpid(pid: pid_t) -> ProcessTerminationStatus {
   var status: CInt = 0
   if waitpid(pid, &status, 0) < 0 {
-    preconditionFailure("waitpid() failed")
+    requirementFailure("waitpid() failed")
   }
   if (WIFEXITED(status)) {
     return .Exit(Int(WEXITSTATUS(status)))
   }
   if (WIFSIGNALED(status)) {
     return .Signal(Int(WTERMSIG(status)))
   }
-  preconditionFailure("did not understand what happened to child process")
+  requirementFailure("did not understand what happened to child process")
 }
 
 public func runChild(args: [String])
@@ -215,10 +215,10 @@ public func runChild(args: [String])
   let stderr = _readAll(stderrFD)
 
   if close(stdoutFD) != 0 {
-    preconditionFailure("close() failed")
+    requirementFailure("close() failed")
   }
   if close(stderrFD) != 0 {
-    preconditionFailure("close() failed")
+    requirementFailure("close() failed")
   }
   let status = posixWaitpid(pid)
   return (stdout, stderr, status)

Diff for: stdlib/public/core/Assert.swift

@@ -14,7 +14,7 @@
 ///
 /// Use this function for internal sanity checks that are active
 /// during testing but do not impact performance of shipping code.
-/// To check for invalid usage in Release builds; see `precondition`.
+/// To check for invalid usage in Release builds; see `require`.
 ///
 /// * In playgrounds and -Onone builds (the default for Xcode's Debug
 ///   configuration): if `condition` evaluates to false, stop program
@@ -58,7 +58,7 @@ public func assert(
 ///   to satisfy that assumption in -Ounchecked builds is a serious
 ///   programming error.
 @_transparent
-public func precondition(
+public func require(
   @autoclosure condition: () -> Bool,
   @autoclosure _ message: () -> String = String(),
   file: StaticString = __FILE__, line: UInt = __LINE__
@@ -81,7 +81,7 @@ public func precondition(
 /// reach the call (e.g. in the `default` case of a `switch` where you
 /// have knowledge that one of the other cases must be satisfied). To
 /// protect code from invalid usage in Release builds; see
-/// `preconditionFailure`.
+/// `requirementFailure`.
 ///
 /// * In playgrounds and -Onone builds (the default for Xcode's Debug
 ///   configuration) stop program execution in a debuggable state
@@ -121,7 +121,7 @@ public func assertionFailure(
 ///   function will never be called. Failure to satisfy that assumption
 ///   is a serious programming error.
 @_transparent @noreturn
-public func preconditionFailure(
+public func requirementFailure(
   @autoclosure message: () -> String = String(),
   file: StaticString = __FILE__, line: UInt = __LINE__
 ) {

Diff for: stdlib/public/core/ErrorType.swift

@@ -50,7 +50,7 @@ public func _bridgeErrorProtocolToNSError(error: ErrorProtocol) -> AnyObject
 /// throws an error.
 @_silgen_name("swift_unexpectedError")
 public func _unexpectedError(error: ErrorProtocol) {
-  preconditionFailure("'try!' expression unexpectedly raised an error: \(String(reflecting: error))")
+  requirementFailure("'try!' expression unexpectedly raised an error: \(String(reflecting: error))")
 }
 
 /// Invoked by the compiler when code at top level throws an uncaught error.

Diff for: stdlib/public/core/ExistentialCollection.swift.gyb

@@ -459,7 +459,7 @@ public struct ${Self} : ${Traversal}Index {
   internal var _box: _${Traversal}IndexBoxProtocol
 
   public func _distanceTo(other: ${Self}) -> ${Self}.Distance {
-    precondition(
+    require(
       self._typeID == other._typeID,
       "distance: base index types differ.")
     return self._box._distanceTo(other._box)
@@ -473,7 +473,7 @@ public struct ${Self} : ${Traversal}Index {
 ///   identical.
 @warn_unused_result
 public func == (lhs: ${Self}, rhs: ${Self}) -> Bool {
-  precondition(lhs._typeID == rhs._typeID, "base index types differ.")
+  require(lhs._typeID == rhs._typeID, "base index types differ.")
   return lhs._box.equals(rhs._box)
 }
 % end

Diff for: stdlib/public/core/Index.swift

@@ -87,7 +87,7 @@ public protocol ForwardIndex : _Incrementable {
   ///
   /// The range check, if performed, is equivalent to:
   ///
-  ///     precondition(bounds.contains(index))
+  ///     require(bounds.contains(index))
   ///
   /// Use this function to perform a cheap range check for QoI purposes when
   /// memory safety is not a concern.  Do not rely on this range check for
@@ -105,10 +105,10 @@ public protocol ForwardIndex : _Incrementable {
   ///
   /// The range check, if performed, is equivalent to:
   ///
-  ///     precondition(
+  ///     require(
   ///       bounds.contains(range.startIndex) ||
   ///       range.startIndex == bounds.endIndex)
-  ///     precondition(
+  ///     require(
   ///       bounds.contains(range.endIndex) ||
   ///       range.endIndex == bounds.endIndex)
   ///

Diff for: stdlib/public/core/Mirror.swift

@@ -452,7 +452,7 @@ extension Mirror.DisplayStyle {
     case .IndexContainer: self = .Collection
     case .KeyContainer: self = .Dictionary
     case .MembershipContainer: self = .Set
-    case .Container: preconditionFailure("unused!")
+    case .Container: requirementFailure("unused!")
     case .Optional: self = .Optional
     case .ObjCObject: self = .Class
     }

Diff for: stdlib/public/core/Sequence.swift

@@ -33,7 +33,7 @@ public protocol IteratorProtocol {
   ///   since the copy was made, and no preceding call to `self.next()`
   ///   has returned `nil`.  Specific implementations of this protocol
   ///   are encouraged to respond to violations of this requirement by
-  ///   calling `preconditionFailure("...")`.
+  ///   calling `requirementFailure("...")`.
   @warn_unused_result
   mutating func next() -> Element?
 }

Diff for: test/1_stdlib/BridgeStorage.swift.gyb

@@ -87,24 +87,24 @@ struct BridgeObject<NativeType : AnyObject, ObjCType : AnyObject>
   }
 
   var nativeInstance: Native {
-    precondition(isNative)
+    require(isNative)
     return Builtin.bridgeFromRawPointer(rawObject)
   }
 
   var nativeInstance_noSpareBits: Native {
-    precondition(isNative)
-    precondition(spareBits == 0)
+    require(isNative)
+    require(spareBits == 0)
     return Builtin.bridgeFromRawPointer(rawObject)
   }
 
   mutating func isUniquelyReferenced_native_noSpareBits() -> Bool {
-    precondition(isNative)
-    precondition(spareBits == 0)
+    require(isNative)
+    require(spareBits == 0)
     return _isUnique_native(&object)
   }
 
   var objCInstance: ObjC {
-    precondition(isObjC)
+    require(isObjC)
     return Builtin.bridgeFromRawPointer(rawObject)
   }
 

Diff for: test/1_stdlib/ManagedBuffer.swift

@@ -104,7 +104,7 @@ final class TestManagedBuffer<T> : ManagedBuffer<CountAndCapacity,T> {
 
   func append(x: T) {
     let count = self.count
-    precondition(count + 2 <= capacity)
+    require(count + 2 <= capacity)
 
     withUnsafeMutablePointerToElements {
       (p: UnsafeMutablePointer<T>)->() in

Diff for: test/Constraints/diagnostics.swift

@@ -140,7 +140,7 @@ func rdar21080030() {
 }
 
 // <rdar://problem/21248136> QoI: problem with return type inference mis-diagnosed as invalid arguments
-func r21248136<T>() -> T { preconditionFailure() } // expected-note 2 {{in call to function 'r21248136'}}
+func r21248136<T>() -> T { requirementFailure() } // expected-note 2 {{in call to function 'r21248136'}}
 
 r21248136()            // expected-error {{generic parameter 'T' could not be inferred}}
 let _ = r21248136()    // expected-error {{generic parameter 'T' could not be inferred}}

Diff for: test/Constraints/function.swift

@@ -42,7 +42,7 @@ testArgumentShuffle(third: 1, 2)
 
 func rejectsAssertStringLiteral() {
   assert("foo") // expected-error {{cannot convert value of type 'String' to expected argument type 'Bool'}}
-  precondition("foo") // expected-error {{cannot convert value of type 'String' to expected argument type 'Bool'}}
+  require("foo") // expected-error {{cannot convert value of type 'String' to expected argument type 'Bool'}}
 }