* Make env var eval order during "use" deterministic
Fixes#726.
* Merge delta after getting config
To make sure env vars are all in the engine state and not in the stack.
* Use only $nu.env.PWD for getting current directory
Because setting and reading to/from std::env changes the global state
shich is problematic if we call `cd` from multiple threads (e.g., in a
`par-each` block).
With this change, when engine-q starts, it will either inherit existing
PWD env var, or create a new one from `std::env::current_dir()`.
Otherwise, everything that needs the current directory will get it from
`$nu.env.PWD`. Each spawned external command will get its current
directory per-process which should be thread-safe.
One thing left to do is to patch nu-path for this as well since it uses
`std::env::current_dir()` in its expansions.
* Rename nu-path functions
*_with is not *_relative which should be more descriptive and frees
"with" for use in a followup commit.
* Clone stack every each iter; Fix some commands
Cloning the stack each iteration of `each` makes sure we're not reusing
PWD between iterations.
Some fixes in commands to make them use the new PWD.
* Post-rebase cleanup, fmt, clippy
* Change back _relative to _with in nu-path funcs
Didn't use the idea I had for the new "_with".
* Remove leftover current_dir from rebase
* Add cwd sync at merge_delta()
This makes sure the parser and completer always have up-to-date cwd.
* Always pass absolute path to glob in ls
* Do not allow PWD a relative path; Allow recovery
Makes it possible to recover PWD by proceeding with the REPL cycle.
* Clone stack in each also for byte/string stream
* (WIP) Start moving env variables to engine state
* (WIP) Move env vars to engine state (ugly)
Quick and dirty code.
* (WIP) Remove unused mut and args; Fmt
* (WIP) Fix dataframe tests
* (WIP) Fix missing args after rebase
* (WIP) Clone only env vars, not the whole stack
* (WIP) Add env var clone to `for` loop as well
* Minor edits
* Refactor merge_delta() to include stack merging.
Less error-prone than doing it manually.
* Clone env for each `update` command iteration
* Mark env var hidden only when found in eng. state
* Fix clippt warnings
* Add TODO about env var reading
* Do not clone empty environment in loops
* Remove extra cwd collection
* Split current_dir() into str and path; Fix autocd
* Make completions respect PWD env var
