Update for SE-0055: Making pointer nullability explicit.

See swiftlang/swift#1878.

Author: jrose-apple

Sources/POSIX/fopen.swift

@@ -18,7 +18,8 @@ public enum FopenMode: String {
 }
 
 public func fopen(_ path: String, mode: FopenMode = .Read) throws -> UnsafeMutablePointer<FILE> {
-    let f = libc.fopen(path, mode.rawValue)
-    guard f != nil else { throw SystemError.fopen(errno, path) }
+    guard let f = libc.fopen(path, mode.rawValue) else {
+        throw SystemError.fopen(errno, path)
+    }
     return f
 }

Sources/POSIX/opendir.swift

@@ -13,8 +13,9 @@ import var libc.errno
 import func libc.opendir
 
 public func opendir(_ path: String) throws -> DirHandle {
-    let d = libc.opendir(path)
-    guard d != nil else { throw SystemError.opendir(errno, path) }
+    guard let d = libc.opendir(path) else {
+        throw SystemError.opendir(errno, path)
+    }
     return d
 }
 

Sources/POSIX/popen.swift

@@ -31,7 +31,7 @@ public func popen(_ arguments: [String], redirectStandardError: Bool = false, en
 
         // Create the file actions to use for spawning.
 #if os(OSX)
-        var fileActions: posix_spawn_file_actions_t = nil
+        var fileActions: posix_spawn_file_actions_t? = nil
 #else
         var fileActions = posix_spawn_file_actions_t()
 #endif

Sources/POSIX/system.swift

@@ -42,11 +42,16 @@ public func system(_ arguments: [String], environment: [String:String] = [:]) th
 public func system() {}
 
 
+#if os(OSX)
+typealias swiftpm_posix_spawn_file_actions_t = posix_spawn_file_actions_t?
+#else
+typealias swiftpm_posix_spawn_file_actions_t = posix_spawn_file_actions_t
+#endif
 
 /// Convenience wrapper for posix_spawn.
-func posix_spawnp(_ path: String, args: [String], environment: [String: String] = [:], fileActions: posix_spawn_file_actions_t? = nil) throws -> pid_t {
-    let argv = args.map{ $0.withCString(strdup) }
-    defer { for arg in argv { free(arg) } }
+func posix_spawnp(_ path: String, args: [String], environment: [String: String] = [:], fileActions: swiftpm_posix_spawn_file_actions_t? = nil) throws -> pid_t {
+    let argv: [UnsafeMutablePointer<CChar>?] = args.map{ $0.withCString(strdup) }
+    defer { for case let arg? in argv { free(arg) } }
 
     var environment = environment
 #if Xcode
@@ -60,8 +65,8 @@ func posix_spawnp(_ path: String, args: [String], environment: [String: String]
         }
     }
 
-    let env = environment.map{ "\($0.0)=\($0.1)".withCString(strdup) }
-    defer { env.forEach{ free($0) } }
+    let env: [UnsafeMutablePointer<CChar>?] = environment.map{ "\($0.0)=\($0.1)".withCString(strdup) }
+    defer { for case let arg? in env { free(arg) } }
 
     var pid = pid_t()
     let rv: Int32

Sources/PackageDescription/Package.swift

@@ -69,9 +69,14 @@ public final class Package {
         // to get the interpreter to dump the package when attempting to load a
         // manifest.
 
-        if let fileNoOptIndex = Process.arguments.index(of: "-fileno"),
-               fileNo = Int32(Process.arguments[fileNoOptIndex + 1]) {
-            dumpPackageAtExit(self, fileNo: fileNo)
+        // FIXME: Additional hackery here to avoid accessing 'arguments' in a
+        // process whose 'main' isn't generated by Swift.
+        // See https://bugs.swift.org/browse/SR-1119.
+        if Process.argc > 0 {
+            if let fileNoOptIndex = Process.arguments.index(of: "-fileno"),
+                   fileNo = Int32(Process.arguments[fileNoOptIndex + 1]) {
+                dumpPackageAtExit(self, fileNo: fileNo)
+            }
         }
     }
 }

Sources/Utility/File.swift

@@ -56,9 +56,7 @@ public class FileLineGenerator: IteratorProtocol, Sequence {
     }
 
     deinit {
-        if fp != nil {
-            fclose(fp)
-        }
+        fclose(fp)
     }
 
     public func next() -> String? {

Sources/Utility/POSIXConvenience.swift

@@ -11,11 +11,9 @@
 import POSIX
 
 public func fopen(_ path: String..., mode: FopenMode = .Read, body: (UnsafeMutablePointer<FILE>) throws -> Void) throws {
-    var fp = try POSIX.fopen(Path.join(path), mode: mode)
-    defer { if fp != nil { fclose(fp) } }
+    let fp = try POSIX.fopen(Path.join(path), mode: mode)
+    defer { fclose(fp) }
     try body(fp)
-    fclose(fp)  // defer is not necessarily immediate
-    fp = nil
 }
 
 @_exported import func POSIX.fputs

Sources/Utility/walk.swift

@@ -62,7 +62,7 @@ public func walk(_ paths: String..., recursing: (String) -> Bool) -> RecursibleD
  A generator for a single directory’s contents
 */
 private class DirectoryContentsGenerator: IteratorProtocol {
-    private let dirptr: DirHandle
+    private let dirptr: DirHandle?
     private let path: String
 
     private init(path: String) {
@@ -72,16 +72,16 @@ private class DirectoryContentsGenerator: IteratorProtocol {
     }
 
     deinit {
-        if dirptr != nil { closedir(dirptr) }
+        if let openeddir = dirptr { closedir(openeddir) }
     }
 
     func next() -> dirent? {
-        if dirptr == nil { return nil }  // yuck, silently ignoring the error to maintain this pattern
+        guard let validdir = dirptr else { return nil }  // yuck, silently ignoring the error to maintain this pattern
 
         while true {
             var entry = dirent()
-            var result: UnsafeMutablePointer<dirent> = nil
-            guard readdir_r(dirptr, &entry, &result) == 0 else { continue }
+            var result: UnsafeMutablePointer<dirent>? = nil
+            guard readdir_r(validdir, &entry, &result) == 0 else { continue }
             guard result != nil else { return nil }
 
             switch (Int32(entry.d_type), entry.d_name.0, entry.d_name.1, entry.d_name.2) {