Fix rendering when continuation prompt is an empty string (PowerShell#2875)

Author: daxian-dbw

PSReadLine/Render.cs

@@ -205,8 +205,11 @@ void RenderOneChar(char charToRender, bool toEmphasize)
  // the previous rendering string.
  activeColor = string.Empty;
 
- UpdateColorsIfNecessary(Options._continuationPromptColor);
- _consoleBufferLines[currentLogicalLine].Append(Options.ContinuationPrompt);
+ if (Options.ContinuationPrompt.Length > 0)
+ {
+ UpdateColorsIfNecessary(Options._continuationPromptColor);
+ _consoleBufferLines[currentLogicalLine].Append(Options.ContinuationPrompt);
+ }
 
  if (inSelectedRegion)
  {
@@ -465,6 +468,13 @@ private bool RenderErrorPrompt(RenderData renderData, string defaultColor)
  /// </summary>
  private int PhysicalLineCount(int columns, bool isFirstLogicalLine, out int lenLastPhysicalLine)
  {
+ if (columns == 0)
+ {
+ // This could happen for a new logical line with an empty-string continuation prompt.
+ lenLastPhysicalLine = 0;
+ return 1;
+ }
+
  int cnt = 1;
  int bufferWidth = _console.BufferWidth;
 

test/RenderTest.cs

@@ -203,6 +203,65 @@ public void MultiLine()
  _.Enter, CheckThat(() => AssertCursorLeftTopIs(0, 2))));
  }
 
+ [SkippableFact]
+ public void MultiLine_ScreenCheck()
+ {
+ TestSetup(KeyMode.Cmd);
+
+ var defaultContinuationPrompt = PSConsoleReadLineOptions.DefaultContinuationPrompt;
+ var defaultContinuationPromptColors = Tuple.Create(_console.ForegroundColor, _console.BackgroundColor);
+
+ Test("@'\n\n hello\n\n world\n'@",
+ Keys(
+ "@'", _.Enter, _.Enter,
+ " hello", _.Enter, _.Enter,
+ " world", _.Enter, "'@",
+ CheckThat(() => AssertScreenIs(6,
+ TokenClassification.String, "@'",
+ NextLine,
+ defaultContinuationPromptColors, defaultContinuationPrompt,
+ NextLine,
+ defaultContinuationPromptColors, defaultContinuationPrompt,
+ TokenClassification.String, " hello",
+ NextLine,
+ defaultContinuationPromptColors, defaultContinuationPrompt,
+ NextLine,
+ defaultContinuationPromptColors, defaultContinuationPrompt,
+ TokenClassification.String, " world",
+ NextLine,
+ defaultContinuationPromptColors, defaultContinuationPrompt,
+ TokenClassification.String, "'@"))
+ ));
+
+ string emptyLine = new string(' ', _console.BufferWidth);
+ // Set the continuation prompt to be an empty string.
+ var setOption = new SetPSReadLineOption { ContinuationPrompt = string.Empty };
+ PSConsoleReadLine.SetOptions(setOption);
+
+ try
+ {
+ Test("@'\n\n hello\n\n world\n'@",
+ Keys(
+ "@'", _.Enter, _.Enter,
+ " hello", _.Enter, _.Enter,
+ " world", _.Enter, "'@",
+ CheckThat(() => AssertScreenIs(6,
+ TokenClassification.String, "@'", NextLine,
+ TokenClassification.None, emptyLine,
+ TokenClassification.String, " hello", NextLine,
+ TokenClassification.None, emptyLine,
+ TokenClassification.String, " world", NextLine,
+ TokenClassification.String, "'@"))
+ ));
+ }
+ finally
+ {
+ // Restore to the default continuation prompt.
+ setOption.ContinuationPrompt = defaultContinuationPrompt;
+ PSConsoleReadLine.SetOptions(setOption);
+ }
+ }
+
  [SkippableFact]
  public void LongLine()
  {