Reset all VT attributes for PromptText if it contains VT sequences (#1544)

Author: daxian-dbw

PSReadLine/Cmdlets.cs

@@ -342,7 +342,29 @@ public object ContinuationPromptColor
         /// If the prompt function is pure, this value can be inferred, e.g.
         /// the default prompt will use "> " for this value.
         /// </summary>
-        public string[] PromptText { get; set; }
+        public string[] PromptText
+        {
+            get => _promptText;
+            set
+            {
+                _promptText = value;
+                if (_promptText == null || _promptText.Length == 0)
+                    return;
+
+                // For texts with VT sequences, reset all attributes if not already.
+                // We only handle the first 2 elements because that's all will potentially be used.
+                int minLength = _promptText.Length == 1 ? 1 : 2;
+                for (int i = 0; i < minLength; i ++)
+                {
+                    var text = _promptText[i];
+                    if (text.Contains('\x1b') && !text.EndsWith("\x1b[0m", StringComparison.Ordinal))
+                    {
+                        _promptText[i] = string.Concat(text, "\x1b[0m");
+                    }
+                }
+            }
+        }
+        private string[] _promptText;
 
         public object DefaultTokenColor
         {

PSReadLine/Render.cs

@@ -444,9 +444,13 @@ private bool RenderErrorPrompt(RenderData renderData, string defaultColor)
                 {
                     string color = renderData.errorPrompt ? _options._errorColor : defaultColor;
                     _console.Write(color);
+                    _console.Write(promptText);
+                    _console.Write("\x1b[0m");
+                }
+                else
+                {
+                    _console.Write(promptText);
                 }
-                _console.Write(promptText);
-                _console.Write("\x1b[0m");
             }
 
             return true;

test/OptionsTest.cs

@@ -131,6 +131,45 @@ public void SetInvalidColorOptions()
             Assert.True(throws, "Invalid color value should throw");
         }
 
+        [SkippableFact]
+        public void SetPromptTextOption()
+        {
+            // For prompt texts with VT sequences, reset all attributes if not already.
+            string[] promptTexts_1 = new[] { "\x1b[91m> " };
+            string[] promptTexts_2 = new[] { "\x1b[91m> ", "\x1b[92m> ", "\x1b[93m> " };
+            string[] promptTexts_3 = new[] { "> " };
+            string[] promptTexts_4 = new[] { "> ", "] " };
+            string[] promptTexts_5 = new[] { "\x1b[93m> \x1b[0m" };
+
+            PSConsoleReadLine.SetOptions(new SetPSReadLineOption {
+                PromptText = promptTexts_1,
+            });
+            Assert.Equal("\x1b[91m> \x1b[0m", promptTexts_1[0]);
+
+            PSConsoleReadLine.SetOptions(new SetPSReadLineOption {
+                PromptText = promptTexts_2,
+            });
+            Assert.Equal("\x1b[91m> \x1b[0m", promptTexts_2[0]);
+            Assert.Equal("\x1b[92m> \x1b[0m", promptTexts_2[1]);
+            Assert.Equal("\x1b[93m> ", promptTexts_2[2]);
+
+            PSConsoleReadLine.SetOptions(new SetPSReadLineOption {
+                PromptText = promptTexts_3,
+            });
+            Assert.Equal("> ", promptTexts_3[0]);
+
+            PSConsoleReadLine.SetOptions(new SetPSReadLineOption {
+                PromptText = promptTexts_4,
+            });
+            Assert.Equal("> ", promptTexts_4[0]);
+            Assert.Equal("] ", promptTexts_4[1]);
+
+            PSConsoleReadLine.SetOptions(new SetPSReadLineOption {
+                PromptText = promptTexts_5,
+            });
+            Assert.Equal("\x1b[93m> \x1b[0m", promptTexts_5[0]);
+        }
+
         [SkippableFact]
         [ExcludeFromCodeCoverage]
         public void UselessStuffForBetterCoverage()