Best to review one commit at a time, since two of the commits are 100%
autogenerated changes from running `ruff format`:
- Install and use `ruff format` instead of black for code formatting.
- Output of `ruff format .` in the `langchain` package.
- Use `ruff format` in experimental package.
- Format changes in experimental package by `ruff format`.
- Manual formatting fixes to make `ruff .` pass.
Both black and mypy expect a list of files or directories as input.
As-is the Makefile computes a list files changed relative to the last
commit; these are passed to black and mypy in the `format_diff` and
`lint_diff` targets. This is done by way of the Makefile variable
`PYTHON_FILES`. This is to save time by skipping running mypy and black
over the whole source tree.
When no changes have been made, this variable is empty, so the call to
black (and mypy) lacks input files. The call exits with error causing
the Makefile target to error out with:
```bash
$ make format_diff
poetry run black
Usage: black [OPTIONS] SRC ...
One of 'SRC' or 'code' is required.
make: *** [format_diff] Error 1
```
This is unexpected and undesirable, as the naive caller (that's me! 😄 )
will think something else is wrong. This commit smooths over this by
short circuiting when `PYTHON_FILES` is empty.
Since the refactoring into sub-projects `libs/langchain` and
`libs/experimental`, the `make` targets `format_diff` and `lint_diff` do
not work anymore when running `make` from these subdirectories. Reason
is that
```
PYTHON_FILES=$(shell git diff --name-only --diff-filter=d master | grep -E '\.py$$|\.ipynb$$')
```
generates paths from the project's root directory instead of the
corresponding subdirectories. This PR fixes this by adding a
`--relative` command line option.
- Tag maintainer: @baskaryan
Bagatur