## Summary
Garbage collect ASTs once we are done checking a given file. Queries
with a cross-file dependency on the AST will reparse the file on demand.
This reduces ty's peak memory usage by ~20-30%.
The primary change of this PR is adding a `node_index` field to every
AST node, that is assigned by the parser. `ParsedModule` can use this to
create a flat index of AST nodes any time the file is parsed (or
reparsed). This allows `AstNodeRef` to simply index into the current
instance of the `ParsedModule`, instead of storing a pointer directly.
The indices are somewhat hackily (using an atomic integer) assigned by
the `parsed_module` query instead of by the parser directly. Assigning
the indices in source-order in the (recursive) parser turns out to be
difficult, and collecting the nodes during semantic indexing is
impossible as `SemanticIndex` does not hold onto a specific
`ParsedModuleRef`, which the pointers in the flat AST are tied to. This
means that we have to do an extra AST traversal to assign and collect
the nodes into a flat index, but the small performance impact (~3% on
cold runs) seems worth it for the memory savings.
Part of https://github.com/astral-sh/ty/issues/214.
## Summary
For reasons I haven't investigated, this speeds up the resolver about 2x
(from 6.404s to 3.612s on an extremely large codebase).
## Test Plan
\cc @BurntSushi
```
[andrew@duff rippling]$ time ruff analyze graph --preview > /dev/null
real 3.274
user 16.039
sys 7.609
maxmem 11631 MB
faults 0
[andrew@duff rippling]$ time ruff-patch analyze graph --preview > /dev/null
real 1.841
user 14.625
sys 3.639
maxmem 7173 MB
faults 0
[andrew@duff rippling]$ time ruff-patch2 analyze graph --preview > /dev/null
real 2.087
user 15.333
sys 4.869
maxmem 8642 MB
faults 0
```
Where that's `main`, then (`ruff-patch`) using the version with no
`File`, no `SemanticModel`, then (`ruff-patch2`) using `File`.
## Summary
This PR adds an experimental Ruff subcommand to generate dependency
graphs based on module resolution.
A few highlights:
- You can generate either dependency or dependent graphs via the
`--direction` command-line argument.
- Like Pants, we also provide an option to identify imports from string
literals (`--detect-string-imports`).
- Users can also provide additional dependency data via the
`include-dependencies` key under `[tool.ruff.import-map]`. This map uses
file paths as keys, and lists of strings as values. Those strings can be
file paths or globs.
The dependency resolution uses the red-knot module resolver which is
intended to be fully spec compliant, so it's also a chance to expose the
module resolver in a real-world setting.
The CLI is, e.g., `ruff graph build ../autobot`, which will output a
JSON map from file to files it depends on for the `autobot` project.
Ibraheem Ahmed
Micha Reiser
Charlie Marsh