Preexec hook for REPL

Feature or enhancement

Proposal:

Background

In VS Code we override PS1 to enable shell integration, this currently gives VS Code understanding of where the commands are and what they are. This provides a few features:

Command decorations with visualization of exit/error status:

Command navigation (cmd/ctrl+up/down):

Run recent (ctrl+alt+r):

To give an example of what's possible with shell integration, here's our experimental VS Code-native PowerShell intellisense:

And multi-line sticky scroll:

Request

Something we needed to work around for Python was the lack of a pre-execution hook, we would normally print \x1b[633;C\a at the end of a command just before it's run such that VS Code knows where that marker is. Currently we have to stick that at the start of the command input though which can degrade the experience, especially when VS Code attempts to figure out that command has been run manually.

To visualization of the problem, see the A, B, C, D markers in our python REPL:

Compare this to PowerShell which positions them correctly:

Shell integration script included in VS Code's python extension: https://github.com/microsoft/vscode-python/blob/main/python_files/pythonrc.py

I'm not a Python dev so I'm not sure what such an API would look like, but we essentially need a hook to run arbitrary code immediately before the REPL runs the command, something like this:

class MyPreexec:
    def __str__(self):
      return "preexec"

sys.preexec = MyPreexec()

cc @anthonykim1 @brettcannon

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response

Linked PRs

• gh-144724
• gh-157241

首先检查所链接的 VS Code Python extension 中 python_files/pythonrc.py 的 Python REPL 执行路径和 shell integration 示例。阅读所链接的 PR gh-144724 和 gh-157241，以了解现有工作和相关决策。当 REPL integrations 可以使用一个有文档说明的 pre-execution hook，且其行为已由相关测试覆盖时，即视为完成。