Merge pull request #14251 from vedantk/pretty-print

Author: swift-ci

stdlib/public/core/DebuggerSupport.swift

@@ -170,6 +170,11 @@ public enum _DebuggerSupport {
     if isRoot || collectionStatus.isCollection { return true }
     let count = Int(mirror.children.count)
     if count > 0 { return true }
+    if let ds = mirror.displayStyle {
+      if ds == .`class` {
+        return true
+      }
+    }
     if let sc = mirror.superclassMirror {
       return ivarCount(mirror: sc) > 0
     } else {

test/stdlib/BridgedObjectDebuggerSupport.swift

@@ -0,0 +1,98 @@
+// RUN: %target-run-simple-swift
+// REQUIRES: executable_test, objc_interop
+
+import Foundation
+import StdlibUnittest
+
+let StringForPrintObjectTests = TestSuite("StringForPrintObject")
+
+// Wrap stringForPrintObject for convenience. Note that the debugger uses
+// something slightly different to pretty-print (see: debugVal()).
+func printObj<T>(_ x: T) -> String {
+  return _DebuggerSupport.stringForPrintObject(x)
+}
+
+// Check if @x has a reference type.
+func hasReferenceType<T>(_ x: T) -> Bool {
+  return _canBeClass(T.self) == 1
+}
+
+// The debugger uses unsafeBitCast to take an arbitrary address and cast it to
+// AnyObject. Mimic that operation here.
+func debugVal<T>(_ x: inout T) -> String {
+  if !hasReferenceType(x) {
+    return printObj(x)
+  }
+  return withUnsafePointer(to: &x) {
+    return _DebuggerSupport.stringForPrintObject(Swift.unsafeBitCast($0.pointee, to: AnyObject.self))
+  }
+}
+
+StringForPrintObjectTests.test("Basic") {
+  var a = "Hello World" as NSString
+  let a_printed = printObj(a)
+  let a_debug = debugVal(&a)
+  expectEqual("Hello World", String(reflecting: a))
+  expectEqual("Hello World\n", a_printed)
+  expectEqual(a_printed, a_debug)
+}
+
+StringForPrintObjectTests.test("NSStringFromStringLiteral") {
+  var a = Foundation.NSString(stringLiteral: "Hello World")
+  let a_printed = printObj(a)
+  let a_debug = debugVal(&a)
+  expectEqual("Hello World", String(reflecting: a))
+  expectEqual("Hello World\n", a_printed)
+  expectEqual(a_printed, a_debug)
+}
+
+StringForPrintObjectTests.test("NSStringFromUnsafeBuffer") {
+  let buf = UnsafeMutablePointer<Int8>.allocate(capacity: 8)
+  buf[0] = 65
+  buf[1] = 0
+  var a = Foundation.NSString(utf8String: buf)!
+  let a_printed = printObj(a)
+  let a_debug = debugVal(&a)
+  expectEqual("A", String(reflecting: a))
+  expectEqual("A\n", a_printed)
+  expectEqual(a_printed, a_debug)
+  buf.deallocate()
+}
+
+StringForPrintObjectTests.test("ArrayOfStrings") {
+  var a = ["Hello World" as NSString]
+  let a_printed = printObj(a)
+  let a_debug = debugVal(&a)
+  expectEqual("[Hello World]", String(reflecting: a))
+  expectEqual("▿ 1 element\n  - 0 : Hello World\n", a_printed)
+  expectEqual(a_printed, a_debug)
+}
+
+struct StructWithOneMember {
+  var a = "Hello World" as NSString
+}
+
+StringForPrintObjectTests.test("StructWithOneMember") {
+  var a = StructWithOneMember()
+  let a_printed = printObj(StructWithOneMember())
+  let a_debug = debugVal(&a)
+  expectEqual("main.StructWithOneMember(a: Hello World)", String(reflecting: a))
+  expectEqual("▿ StructWithOneMember\n  - a : Hello World\n", a_printed)
+  expectEqual(a_printed, a_debug)
+}
+
+struct StructWithTwoMembers {
+  var a = 1
+  var b = "Hello World" as NSString
+}
+
+StringForPrintObjectTests.test("StructWithTwoMembers") {
+  var a = StructWithTwoMembers()
+  let a_printed = printObj(StructWithTwoMembers())
+  let a_debug = debugVal(&a)
+  expectEqual("main.StructWithTwoMembers(a: 1, b: Hello World)", String(reflecting: a))
+  expectEqual("▿ StructWithTwoMembers\n  - a : 1\n  - b : Hello World\n", a_printed)
+  expectEqual(a_printed, a_debug)
+}
+
+runAllTests()