Allow for stacks to have parents (#11654)

This is another attempt on #11288 

This allows for a `Stack` to have a parent stack (behind an `Arc`). This
is being added to avoid constant stack copying in REPL code.

Concretely the following changes are included here:
- `Stack` can now have a `parent_stack`, pointing to another stack
- variable lookups can fallback to this parent stack (env vars and
everything else is still copied)
- REPL code has been reworked so that we use parenting rather than
cloning. A REPL-code-specific trait helps to ensure that we do not
accidentally trigger a full clone of the main stack
- A property test has been added to make sure that parenting "looks the
same" as cloning for consumers of `Stack` objects

---------

Co-authored-by: Raphael Gaschignard <rtpg@rokkenjima.local>
Co-authored-by: Ian Manske <ian.manske@pm.me>
This commit is contained in:
Raphael Gaschignard
2024-03-10 01:55:39 +09:00
committed by GitHub
parent c90640411d
commit d8f13b36b1
7 changed files with 338 additions and 87 deletions

View File

@ -99,7 +99,7 @@ fn get_editor_commandline(
pub fn get_editor(
engine_state: &EngineState,
stack: &mut Stack,
stack: &Stack,
span: Span,
) -> Result<(String, Vec<String>), ShellError> {
let config = engine_state.get_config();