## Summary
When you specify a source distribution via a path, it can either be a
path to an archive (like a `.tar.gz` file), or a source tree (a
directory). Right now, we handle both paths through the same methods in
the source database. This PR splits them up into separate handlers.
This will make hash generation a little easier, since we need to
generate hashes for archives, but _can't_ generate hashes for source
trees.
It also means that we can now store the unzipped source distribution in
the cache (in the case of archives), and avoid unzipping the source
distribution needlessly on every invocation; and, overall, let's un
enforce clearer expectations between the two routes (e.g., what errors
are possible vs. not), at the cost of duplicating some code.
Closes#2760 (incidentally -- not exactly the motivation for the change,
but it did accomplish it).
## Summary
I think this is a much clearer name for this concept: the set of
"versions" of a given wheel or source distribution. We also use
"Manifest" elsewhere to refer to the set of requirements, constraints,
etc., so this was overloaded.
## Summary
We have a heuristic in `File` that attempts to detect whether a URL is
absolute or relative. However, `contains("://")` is prone to false
positive. In the linked issues, the URLs look like:
```
/packages/5a/d8/4d75d1e4287ad9d051aab793c68f902c9c55c4397636b5ee540ebd15aedf/pytz-2005k.tar.bz2?hash=597b596dc1c2c130cd0a57a043459c3bd6477c640c07ac34ca3ce8eed7e6f30c&remote=4d75d1e4287636b5ee540ebd15aedf/pytz-2005k.tar.bz2#sha256=597b596dc1c2c130cd0a57a043459c3bd6477c640c07ac34ca3ce8eed7e6f30c
```
Which is relative, but includes `://`.
Instead, we should determine whether the URL has a _scheme_ which
matches the `Url` crate internally.
Closes https://github.com/astral-sh/uv/issues/2899.
## Summary
Right now, the path-based wheel cache just looks at the symlink to the
archives directory, checks the timestamp on it, and continues with that
symlink as long as the timestamp is up-to-date.
The HTTP-based wheel meanwhile, uses an intermediary `.http` file, which
includes the HTTP caching information. The `.http` file's payload is
just a path pointing to an entry in the archives directory.
This PR modifies the path-based codepaths to use a similar cache file,
which stores a timestamp along with a path to the archives directory.
The main advantage here is that we can add other data to this cache file
(namely, hashes in the future).
## Test Plan
Beyond existing tests, I also verified that this doesn't require a
version bump:
```
git checkout main
cargo run pip install ~/Downloads/zeal-0.0.1-py3-none-any.whl --cache-dir baz --reinstall
git checkout charlie/manifest
cargo run pip install ~/Downloads/zeal-0.0.1-py3-none-any.whl --cache-dir baz --reinstall
cargo run pip install ~/Downloads/zeal-0.0.1-py3-none-any.whl --cache-dir baz --reinstall --refresh
```
## Summary
I think this is kind of just an oversight. If a wheel is available via
`--find-links`, and the index is "local", we never find it in the cache.
## Test Plan
`cargo test`
## Summary
In all cases, we unzip these immediately after returning. By moving the
unzipping into the database, we can remove a bunch of code (coming in a
separate PR), and pave the way for hash-checking, since hash generation
will _also_ happen in the database, and splitting the caching layers
across the database and the unzipper creates complications.
Closes#2863.
With pubgrub being fast for complex ranges, we can now compute the next
n candidates without taking a performance hit. This speeds up cold cache
`urllib3<1.25.4` `boto3` from maybe 40s - 50s to ~2s. See docstrings for
details on the heuristics.
**Before**

**After**

---
We need two parts of the prefetching, first looking for compatible
version and then falling back to flat next versions. After we selected a
boto3 version, there is only one compatible botocore version remaining,
so when won't find other compatible candidates for prefetching. We see
this as a pattern where we only prefetch boto3 (stack bars), but not
botocore (sequential requests between the stacked bars).

The risk is that we're completely wrong with the guess and cause a lot
of useless network requests. I think this is acceptable since this
mechanism only triggers when we're already on the bad path and we should
simply have fetched all versions after some seconds (assuming a fast
index like pypi).
---
It would be even better if the pubgrub state was copy-on-write so we
could simulate more progress than we actually have; currently we're
guessing what the next version is which could be completely wrong, but i
think this is still a valuable heuristic.
Fixes#170.
## Summary
Is this, perhaps, not totally necessary? It doesn't show up in any
fixtures beyond those that I added recently.
Closes https://github.com/astral-sh/uv/issues/2846.
## Summary
Demonstrates some suboptimal behavior in how we handle invalid metadata,
which are fixed in https://github.com/astral-sh/uv/pull/2834.
The included wheels were modified by-hand to include invalid structures.