Fix AcceptAndGetNext for Forward/ReverseSearchHistory

[sharpchen (sharpchen)]

PR Summary

Fixes #514

The Context

To get AcceptAndGetNext work, _currentHistoryIndex is required to be set before line accepted.

PSReadLine/PSReadLine/BasicEditing.cs

Line 562 in 2984546

if (_singleton._currentHistoryIndex < (_singleton._history.Count - 1))

For Previous/NextHistory, _currentHistoryIndex is set by HistoryRecall:

PSReadLine/PSReadLine/History.cs

Line 936 in 2984546

_currentHistoryIndex = newHistoryIndex;

For Forward/ReverseSearchHistory, _currentHistoryIndex is set by UpdateHistoryDuringInteractiveSearch:

PSReadLine/PSReadLine/History.cs

Line 1138 in 2984546

_currentHistoryIndex = searchFromPoint;

Current Behaviour

1. ✔️ Triggering AcceptAndGetNext during the interactive search works as expected.
2. ❌ Quit the interactive search and press any key doesn't edit the line(e.g. right arrow), it can't load next history after AcceptAndGetNext as expected.
3. ❌ If Behaviour 2 is fixed, when a match from interactive search is accepted by e.g. esc, any edit based on the match doesn't reset _currentHistoryIndex, so AcceptAndGetNext would still proceed from the index of search result.

The Problem

For Behaviour 2, I located the problem come from:

PSReadLine/PSReadLine/ReadLine.cs

Lines 615 to 620 in 2984546

	if (_anyHistoryCommandCount > 0)
	{
	ClearSavedCurrentLine();
	_hashedHistory = null;
	_currentHistoryIndex = _history.Count;
	}

The problem is InteractiveHistorySearch calls SaveCurrentLine() which increments _anyHistoryCommandCount, triggering the reset of _currentHistoryIndex in next input loop, even though the new input didn't edit the current line.

The Solution

_currentHistoryIndex is expected to be reset here only if _savedCurrentLine is identical to the current _buffer.

So the fix simple, just add a guard on it.

    if (_anyHistoryCommandCount > 0)
    {
-        ClearSavedCurrentLine();
-        _hashedHistory = null;
-        _currentHistoryIndex = _history.Count;
+        if (_savedCurrentLine.CommandLine == _buffer.ToString()) {
+            ClearSavedCurrentLine();
+            _hashedHistory = null;
+            _currentHistoryIndex = _history.Count;
+        }
    }
    _anyHistoryCommandCount = 0;

Note

I really doubt this piece of code should be executed after line accepted instead of on any input?
What is the point of trying clearing _savedCurrentLine on every key press?
BTW the name _anyHistoryCommandCount is really confusing, please consider refactoring it to a better name or add comment for why it exists.

PR Checklist

• PR has a meaningful title
  • Use the present tense and imperative mood when describing your changes
• Summarized changes
• Make sure you've added one or more new tests
• Make sure you've tested these changes in terminals that PowerShell is commonly used in (i.e. conhost.exe, Windows Terminal, Visual Studio Code Integrated Terminal, etc.)
• User-facing changes
  • Not Applicable
  • OR
  • Documentation needed at PowerShell-Docs
    • Doc Issue filed:

Microsoft Reviewers: Open in CodeFlow