This commit adds a short section discussing the non-processing of docstrings
besides spacing improvements, mentions comment moving and links to the
AST equivalence discussion. I also added a simple spacing test for good
measure.
Commit history before merge:
* Mention comment non-processing in documentation, add spacing test
* Mention special cases for comment spacing
* Add all special cases, improve wording
- when a trailing comma is specified in any bracket pair, that signals to Black
that this bracket pair needs to be always exploded, e.g. presented as "one
item per line";
- this causes some changes to previously formatted code that erroneously left
trailing commas embedded into single-line expressions;
- internally, Black needs to be able to identify trailing commas that it put
itself compared to pre-existing trailing commas. We do this by using/abusing
lib2to3's `was_checked` attribute. It's True for internally generated
trailing commas and False for pre-existing ones (in fact, for all
pre-existing leaves and nodes).
Fixes#1288
`type: ignore` shouldn't block collapsing a line, since it will still
apply fine to the merged line. This prevents an issue where a reformat
causes it to shift lines and then be merged on a subsequent pass.
There is a downside to this, which is that it can cause a `type:
ignore` to apply to more code than was originally intended. There
might be a way to apply this in a more limited situation, but I'm not
sure what it is.
Fixes#1061.
In #1040 I had convinced myself that the type ignore logic didn't
need anything like the ignored_ids from the type comment logic, but I
was wrong, and we do.
We hit these cases in practice a bunch.
The code introduced in #1027 to detect whether a type comment appeared
after a regular comment in a Line would spuriously misfire when a leaf
was in the comments dict but had an empty list of comments. This can
occur as an artifact of how comments on trailing commas are handled,
it seems.
(This was discovered trying to test black out on mypy.)
