prompt-toolkit / prompt-toolkit/python-prompt-toolkit

`Renderer.reset` is called 3 times during application startup.

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Description

This results in some output escape sequences to be produced multiple times without reason, like showing the cursor.

Renderer.reset() is called three times when we create/start an application, like ptpython for instance:

  • Once Application.__init__()-> Renderer.__init__() -> Renderer.reset().
  • Once Application.__init__() -> Application.reset() ->Renderer.reset().
  • Once Application._run_async() -> Application.__init__() -> Application.reset() ->Renderer.reset().

Each time, we call self.output.show_cursor().

Either we should keep track in the Renderer, which terminal state was changed, and only reset that (cursor shapes changed, cursor hidden/shown, alternate screen entered/left, ...) or we should create the Renderer instance only at the point that the application actually starts in Application._run_async(), so that we only reset once.

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  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by tracing the Renderer.reset() calls through Application.init(), Application.reset(), and Application._run_async(). Compare the two proposed approaches for avoiding repeated terminal-state resets, using ptpython startup to observe the output. Done means application startup no longer emits duplicate escape sequences such as repeated cursor-display commands.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
cli
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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