feat: Navigate prompt history in prompt field via arrow up/down (#4139)

[hannesrudolph]

Fixes #4139

Description

This PR implements hybrid prompt history navigation using arrow up/down keys in the chat input field, providing an intuitive
terminal-like experience that adapts to the user's current context.

Key Features

Hybrid Navigation Sources

• Active conversation: Navigate through recent conversation messages (newest first)
• Starting fresh: Navigate through task history from previous sessions (newest first)

Smart Context Detection

• Automatically detects if user is in an active conversation vs starting fresh
• Seamlessly switches between clineMessages and taskHistory as data sources
• Resets navigation position when switching between history sources

Terminal-like UX

• Arrow Up: Navigate to previous (older) prompts
• Arrow Down: Navigate to next (newer) prompts or return to current input
• Only triggers when cursor is at first/last line of textarea
• Preserves current input when starting navigation
• Restores current input when navigating back to present

Performance & Memory Management

• 100-item history limit to prevent memory issues
• Efficient filtering of empty/whitespace-only messages
• Workspace-aware filtering for task history

Navigation Behavior

1. In Active Conversation:

   • Press ↑ to get most recent conversation message
   • Continue ↑ to go through older conversation messages
   • Press ↓ to move forward through newer messages

2. Starting Fresh (No Active Conversation):

   • Press ↑ to get most recent task from history
   • Continue ↑ to go through older tasks
   • Press ↓ to move forward through newer tasks

3. Edge Cases:

   • Empty conversation history: Navigation does nothing
   • Single prompt with no follow-ups: No navigation (fixed in latest commit)
   • Typing while navigating: Automatically resets navigation state

Technical Implementation

• Custom usePromptHistory hook encapsulates all navigation logic
• Cursor position management for proper UX after navigation
• Comprehensive test coverage for all navigation scenarios
• Integration with existing chat component without breaking changes

[hannesrudolph]

fixing issue where the history was inthe wrong order an it was also pulling from the pool of all history instead of just the workspace.

[hannesrudolph]

The test fail because windows is the problem :P

[mochiya98]

Thanks, it looks good!
There might be issues with setTimeout(..., 0); depending on the update timing, so it might be better to trigger it within useLayoutEffect .
However, since this affects state management more broadly, the implementation might be a bit more complex.

const [inputValue, setInputValue] = useState<{
  value: string;
  afterRender?: "SET_CURSOR_FIRST_LINE" | "SET_CURSOR_LAST_LINE";
}>({
  value: "",
});
useLayoutEffect(() => {
  if (!inputValue.afterRender) return;
  if (inputValue.afterRender === "SET_CURSOR_FIRST_LINE") {
    if (textAreaRef.current) {
      textAreaRef.current.setSelectionRange(0, 0);
    }
  } else if (inputValue.afterRender === "SET_CURSOR_LAST_LINE") {
    if (textAreaRef.current) {
      const lines = historicalPrompt.split("\n");
      const lastLineStart =
        historicalPrompt.length - lines[lines.length - 1].length;
      textAreaRef.current.setSelectionRange(lastLineStart, lastLineStart);
    }
  }
  setInputValue(({ value }) => ({ value }));
}, [inputValue]);

// Usage
setInputValue({
  value: "...",
  afterRender: "SET_CURSOR_FIRST_LINE",
});
setInputValue({
  value: "...",
  afterRender: "SET_CURSOR_LAST_LINE",
});

[daniel-lxs]

Hey @hannesrudolph, I left some minor performance improvements suggestions.

[daniel-lxs]

Tested it and works quite well, pressing up outside a task brings up the newest task. Pressing up inside the task brings up the newest message sent by the user.

LGTM

[mrubens]

It feels unintuitive to me that the up arrow within a task can also bring up messages from other tasks. Is that part of this necessary, or could we just restrict it to navigating through prompts in the current task?

[hannesrudolph]

It feels unintuitive to me that the up arrow within a task can also bring up messages from other tasks. Is that part of this necessary, or could we just restrict it to navigating through prompts in the current task?

It should be restrcited to just the current task already

[hannesrudolph]

It feels unintuitive to me that the up arrow within a task can also bring up messages from other tasks. Is that part of this necessary, or could we just restrict it to navigating through prompts in the current task?

Seems to be pulling up the Starting Fresh (No Active Conversation): behaviour when there is only the initial prompt in the task and no followup user messages.

[daniel-lxs]

Commit cc7bab0 solved the issue for me.

Looks good.

[hannesrudolph]

ok @mrubens try it now!

[hannesrudolph]

@mrubens

[fabb]

there is a problem with the implementation when the prompt is multi line: it is no longer possible to navigate between lines in the current prompt with arrow up/down.

as i wrote in my feature proposal, it should work as other native search fields in vscode that support multiple lines:

If the current field contains multiple lines, then the cursor must be in the first line when pressing arrow up to replace the text with the previous value in history. The cursor stays in the first line in that case. Arrow up can be pressed multiple times to go back in history. Arrow down goes forward in history, but again, only when the cursor is in the last line. The cursor stays in the last line in that case.