Fix PTK shell sometimes not updating auto-suggest when up-arrow is pressed (#5787)

* fix combining consecutive history entries when loading ptk shell

* add test case for combining history items

* add news item for PTK history combining

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Update ptk-history-combining.rst

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Andy Kipp <anki-code@users.noreply.github.com>

news/ptk-history-combining.rst

@@ -0,0 +1,23 @@
+**Added:**
+
+* <news item>
+
+**Changed:**
+
+* <news item>
+
+**Deprecated:**
+
+* <news item>
+
+**Removed:**
+
+* <news item>
+
+**Fixed:**
+
+* prompt toolkit: Fixed autosuggest sometimes not updating when up-arrow is pressed (#5787).
+
+**Security:**
+
+* <news item>

tests/shell/test_ptk_shell.py

@@ -8,6 +8,7 @@ import pytest
 from xonsh.platform import minimum_required_ptk_version
 from xonsh.shell import Shell
 from xonsh.shells.ptk_shell import tokenize_ansi
+from xonsh.shells.ptk_shell.history import PromptToolkitHistory
 
 # verify error if ptk not installed or below min
 
@@ -145,3 +146,24 @@ def test_ptk_default_append_history(cmd, exp_append_history, ptk_shell, monkeypa
         assert len(append_history_calls) == 1
     else:
         assert len(append_history_calls) == 0
+
+
+def test_ptk_combine_history(monkeypatch):
+    """Test that consecutive identical history items are combined into a single item
+    when loading xonsh history items into prompt-toolkit history."""
+
+    def all_items(*args, **kwargs):
+        lines = [
+            "one two three",
+            "four five six",
+            "four five six",
+            "one two three",
+        ]
+        for line in lines:
+            yield {"inp": line}
+
+    monkeypatch.setattr("xonsh.built_ins.XSH.history.all_items", all_items)
+
+    shell_hist = PromptToolkitHistory()
+    hist_strs = list(shell_hist.load_history_strings())
+    assert len(hist_strs) == 3

xonsh/shells/ptk_shell/history.py

@@ -25,11 +25,12 @@ class PromptToolkitHistory(prompt_toolkit.history.History):
         hist = XSH.history
         if hist is None:
             return
+        prev_line = None
         for cmd in hist.all_items(newest_first=True):
             line = cmd["inp"].rstrip()
-            strs = self.get_strings()
-            if len(strs) == 0 or line != strs[-1]:
+            if line != prev_line:
                 yield line
+            prev_line = line
 
     def __getitem__(self, index):
         return self.get_strings()[index]