Fix NullRefEx bug when accessing scriptFile.ReferencedFiles (#838)

* Fix NullRefEx bug when accessing scriptFile.ReferencedFilesThis happens because the ScriptFile ctor does not initialize all itspublic props.  I added initialization for the other public propsexcept for the ScriptAst prop.  I don't see an empty Ast.  Perhaps nullis OK for this prop?This address vscode-powershell bug https://github.com/PowerShell/vscode-powershell/issues/1675Also, for the 2.0.0 branch, we should see if we can use Array.Empty<>()for initialization.  It isn't availble to net45x.  :-(

* Revise ScriptFile prop init to happen within ParseFileContents & add tests

src/PowerShellEditorServices/Workspace/ScriptFile.cs

@@ -26,7 +26,6 @@ public class ScriptFile
             "\n"
         };
 
-        private Token[] scriptTokens;
         private Version powerShellVersion;
 
         #endregion
@@ -116,7 +115,8 @@ public ScriptBlockAst ScriptAst
         /// </summary>
         public Token[] ScriptTokens
         {
-            get { return this.scriptTokens; }
+            get;
+            private set;
         }
 
         /// <summary>
@@ -152,6 +152,7 @@ public ScriptFile(
             this.IsInMemory = Workspace.IsPathInMemory(filePath);
             this.powerShellVersion = powerShellVersion;
 
+            // SetFileContents() calls ParseFileContents() which initializes the rest of the properties.
             this.SetFileContents(textReader.ReadToEnd());
         }
 
@@ -599,6 +600,8 @@ private void ParseFileContents()
 
             try
             {
+                Token[] scriptTokens;
+
 #if PowerShellv5r2
                 // This overload appeared with Windows 10 Update 1
                 if (this.powerShellVersion.Major >= 5 &&
@@ -610,24 +613,26 @@ private void ParseFileContents()
                         Parser.ParseInput(
                             this.Contents,
                             this.FilePath,
-                            out this.scriptTokens,
+                            out scriptTokens,
                             out parseErrors);
                 }
                 else
                 {
                     this.ScriptAst =
                         Parser.ParseInput(
                             this.Contents,
-                            out this.scriptTokens,
+                            out scriptTokens,
                             out parseErrors);
                 }
 #else
                 this.ScriptAst =
                     Parser.ParseInput(
                         this.Contents,
-                        out this.scriptTokens,
+                        out scriptTokens,
                         out parseErrors);
 #endif
+
+                this.ScriptTokens = scriptTokens;
             }
             catch (RuntimeException ex)
             {
@@ -638,7 +643,7 @@ private void ParseFileContents()
                         ex.Message);
 
                 parseErrors = new[] { parseError };
-                this.scriptTokens = new Token[0];
+                this.ScriptTokens = new Token[0];
                 this.ScriptAst = null;
             }
 
@@ -654,6 +659,8 @@ private void ParseFileContents()
             // users should save the file.
             if (IsUntitledPath(this.FilePath))
             {
+                // Need to initialize the ReferencedFiles property to an empty array.
+                this.ReferencedFiles = new string[0];
                 return;
             }
 

test/PowerShellEditorServices.Test/Session/ScriptFileTests.cs

@@ -164,10 +164,10 @@ public void CanAppendToEndOfFile()
         public void FindsDotSourcedFiles()
         {
             string exampleScriptContents =
-                @". .\athing.ps1"+"\r\n"+
-                @". .\somefile.ps1"+"\r\n" +
-                @". .\somefile.ps1"+"\r\n" +
-                @"Do-Stuff $uri"+"\r\n" +
+                @". .\athing.ps1" + "\r\n" +
+                @". .\somefile.ps1" + "\r\n" +
+                @". .\somefile.ps1" + "\r\n" +
+                @"Do-Stuff $uri" + "\r\n" +
                 @". simpleps.ps1";
 
             using (StringReader stringReader = new StringReader(exampleScriptContents))
@@ -532,4 +532,51 @@ private void AssertNewPosition(
             Assert.Equal(expectedColumn, newPosition.Column);
         }
     }
+
+    public class ScriptFileConstructorTests
+    {
+        private static readonly Version PowerShellVersion = new Version("5.0");
+
+        [Fact]
+        public void PropertiesInitializedCorrectlyForFile()
+        {
+            var path = "TestFile.ps1";
+            var scriptFile = ScriptFileChangeTests.CreateScriptFile("");
+
+            Assert.Equal(path, scriptFile.FilePath);
+            Assert.Equal(path, scriptFile.ClientFilePath);
+            Assert.True(scriptFile.IsAnalysisEnabled);
+            Assert.False(scriptFile.IsInMemory);
+            Assert.Empty(scriptFile.ReferencedFiles);
+            Assert.Empty(scriptFile.SyntaxMarkers);
+            Assert.Single(scriptFile.ScriptTokens);
+            Assert.Single(scriptFile.FileLines);
+        }
+
+        [Fact]
+        public void PropertiesInitializedCorrectlyForUntitled()
+        {
+            var path = "untitled:untitled-1";
+
+            // 3 lines and 10 tokens in this script.
+            var script = @"function foo() {
+    'foo'
+}";
+
+            using (StringReader stringReader = new StringReader(script))
+            {
+                // Create an in-memory file from the StringReader
+                var scriptFile = new ScriptFile(path, path, stringReader, PowerShellVersion);
+
+                Assert.Equal(path, scriptFile.FilePath);
+                Assert.Equal(path, scriptFile.ClientFilePath);
+                Assert.True(scriptFile.IsAnalysisEnabled);
+                Assert.True(scriptFile.IsInMemory);
+                Assert.Empty(scriptFile.ReferencedFiles);
+                Assert.Empty(scriptFile.SyntaxMarkers);
+                Assert.Equal(10, scriptFile.ScriptTokens.Length);
+                Assert.Equal(3, scriptFile.FileLines.Count);
+            }
+        }
+    }
 }