Merge pull request #158 from apple/validating-constructors

<rdar://70974921> swift-tsc's AbsolutePath and RelativePath Codable constructors should use validating overloads

Author: jakepetroules

Sources/TSCBasic/Path.swift

@@ -304,7 +304,7 @@ extension AbsolutePath: Codable {
 
     public init(from decoder: Decoder) throws {
         let container = try decoder.singleValueContainer()
-        try self.init(container.decode(String.self))
+        try self.init(validating: container.decode(String.self))
     }
 }
 
@@ -316,7 +316,7 @@ extension RelativePath: Codable {
 
     public init(from decoder: Decoder) throws {
         let container = try decoder.singleValueContainer()
-        try self.init(container.decode(String.self))
+        try self.init(validating: container.decode(String.self))
     }
 }
 

Tests/TSCBasicTests/PathTests.swift

@@ -308,6 +308,10 @@ class PathTests: XCTestCase {
             var path: RelativePath
         }
 
+        struct Baz: Codable, Equatable {
+            var path: String
+        }
+
         do {
             let foo = Foo(path: AbsolutePath("/path/to/foo"))
             let data = try JSONEncoder().encode(foo)
@@ -339,6 +343,22 @@ class PathTests: XCTestCase {
             XCTAssertEqual(bar.path.pathString, "path/to/bar")
             XCTAssertEqual(decodedBar.path.pathString, "path/to/bar")
         }
+
+        do {
+            let data = try JSONEncoder().encode(Baz(path: ""))
+            XCTAssertThrowsError(try JSONDecoder().decode(Foo.self, from: data))
+            XCTAssertNoThrow(try JSONDecoder().decode(Bar.self, from: data)) // empty string is a valid relative path
+        }
+
+        do {
+            let data = try JSONEncoder().encode(Baz(path: "foo"))
+            XCTAssertThrowsError(try JSONDecoder().decode(Foo.self, from: data))
+        }
+
+        do {
+            let data = try JSONEncoder().encode(Baz(path: "/foo"))
+            XCTAssertThrowsError(try JSONDecoder().decode(Bar.self, from: data))
+        }
     }
 
     // FIXME: We also need tests for join() operations.