Improve handling of color in prompts (#1180)

Author: lzybkr

PSReadLine/Cmdlets.cs

@@ -321,7 +321,7 @@ 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; set; }
 
         public object DefaultTokenColor
         {
@@ -667,7 +667,7 @@ public int AnsiEscapeTimeout
 
         [Parameter]
         [ValidateNotNull]
-        public string PromptText { get; set; }
+        public string[] PromptText { get; set; }
 
         [Parameter]
         public ViModeStyle ViModeIndicator

PSReadLine/ReadLine.cs

@@ -774,7 +774,7 @@ private void DelayedOneTimeInitialize()
 
                         if (i >= 0)
                         {
-                            _options.PromptText = evaluatedPrompt.Substring(i);
+                            _options.PromptText = new [] { evaluatedPrompt.Substring(i) };
                         }
                     }
                 }

PSReadLine/Render.cs

@@ -366,18 +366,18 @@ void MaybeEmphasize(int i, string currColor)
         /// </returns>
         private bool RenderErrorPrompt(RenderData renderData, string defaultColor)
         {
-            // We may need to flip the color on the prompt if the error state changed.
-
-            int bufferWidth = _console.BufferWidth;
-            string promptText = _options.PromptText;
-
-            if (string.IsNullOrEmpty(promptText) || _initialY < 0)
+            if (_initialY < 0
+                || _options.PromptText == null
+                || _options.PromptText.Length == 0
+                || String.IsNullOrEmpty(_options.PromptText[0]))
             {
                 // No need to flip the prompt color if either the error prompt is not defined
                 // or the initial cursor point has already been scrolled off the buffer.
                 return false;
             }
 
+            // We may need to flip the color on the prompt if the error state changed.
+
             renderData.errorPrompt = (_parseErrors != null && _parseErrors.Length > 0);
             if (renderData.errorPrompt == _previousRender.errorPrompt)
             {
@@ -388,9 +388,15 @@ private bool RenderErrorPrompt(RenderData renderData, string defaultColor)
             // We need to update the prompt
             _console.SetCursorPosition(_initialX, _initialY);
 
+            string promptText =
+                (renderData.errorPrompt && _options.PromptText.Length == 2)
+                    ? _options.PromptText[1]
+                    : _options.PromptText[0];
+
             // promptBufferCells is the number of visible characters in the prompt
             int promptBufferCells = LengthInBufferCells(promptText);
             bool renderErrorPrompt = false;
+            int bufferWidth = _console.BufferWidth;
 
             if (_console.CursorLeft >= promptBufferCells)
             {
@@ -421,12 +427,15 @@ private bool RenderErrorPrompt(RenderData renderData, string defaultColor)
 
             if (renderErrorPrompt)
             {
-                string color = renderData.errorPrompt ? _options._errorColor : defaultColor;
-                if (renderData.errorPrompt && promptBufferCells != promptText.Length)
+                if (!promptText.Contains('\x1b'))
                 {
-                    promptText = promptText.Substring(promptText.Length - promptBufferCells);
+                    string color = renderData.errorPrompt ? _options._errorColor : defaultColor;
+                    if (renderData.errorPrompt && promptBufferCells != promptText.Length)
+                    {
+                        promptText = promptText.Substring(promptText.Length - promptBufferCells);
+                    }
+                    _console.Write(color);
                 }
-                _console.Write(color);
                 _console.Write(promptText);
                 _console.Write("\x1b[0m");
             }

test/UnitTestReadLine.cs

@@ -354,7 +354,7 @@ private void SetPrompt(string prompt)
             var options = new SetPSReadLineOption {ExtraPromptLineCount = 0};
             if (string.IsNullOrEmpty(prompt))
             {
-                options.PromptText = "";
+                options.PromptText = new [] {""};
                 PSConsoleReadLine.SetOptions(options);
                 return;
             }
@@ -365,7 +365,7 @@ private void SetPrompt(string prompt)
                 if (!char.IsWhiteSpace(prompt[i])) break;
             }
 
-            options.PromptText = prompt.Substring(i);
+            options.PromptText = new [] { prompt.Substring(i) };
 
             var lineCount = 1 + prompt.Count(c => c == '\n');
             if (lineCount > 1)
@@ -474,7 +474,7 @@ private void TestSetup(KeyMode keyMode, params KeyHandler[] keyHandlers)
                 MaximumKillRingCount              = PSConsoleReadLineOptions.DefaultMaximumKillRingCount,
                 ShowToolTips                      = PSConsoleReadLineOptions.DefaultShowToolTips,
                 WordDelimiters                    = PSConsoleReadLineOptions.DefaultWordDelimiters,
-                PromptText                        = "",
+                PromptText                        = new [] {""},
                 Colors = new Hashtable {
                     { "ContinuationPrompt",       MakeCombinedColor(_console.ForegroundColor, _console.BackgroundColor) },
                     { "Emphasis",                 MakeCombinedColor(PSConsoleReadLineOptions.DefaultEmphasisColor, _console.BackgroundColor) },