feat: Add `-Zmsrv-policy` feature flag
### What does this PR try to resolve?
Nothing noticeable....
The intent is to unblock experiments with different compatible MSRV policies like
- #9930
- #10653
- #10903
While I normally don't like PRs that do nothing on their own, this at least allows any one of those efforts to move forward with different people without juggling these base commits for whoever is first to include in their PR
While there isn't an RFC for this yet, this is intended to allow us to experiment to get a better idea of what we should put in an RFC. In some cases, we first do an eRFC for this but I assumed this wouldn't be needed in this case as this builds on rust-lang/rfcs#2495 and, I'm assuming, will be more surgical in nature
### How should we test and review this PR?
The `Summary` changes are largely untested as they will be mostly tested through the future work that builds on this PR. However, I wasn't too concerned about that because the code is relatively trivial.
### Additional information
I chose the name `msrv-policy` to distinguish this unstable feature from `rust-version`. Though those appear in different places (`Cargo.toml` vs `-Z`), I can see them being confusing which was especially apparent when editing `unstable.md` which has an anchor for `rust-version`.
This is a follow up to #12039.
This makes it easier for tools to report less irrelevant information.
I did both `publish = false` and `version = "0.0.0"` to help draw
attention to the fact that these crates are internal (inspired by a
matklad post).
I left `cargo-test-macro` and `cargo-test-support` in for my own
personal bias of one day wanting to see those crates published...
The only one removed that had previously been published was `mdman` but
seeing as that was a `0.0.0`, I'm assuming that was a mistake or just
reserving the name.
Before:
```console
$ cargo unpublished
name published current
==== ========= =======
cargo-platform 0.1.2 0.1.3
cargo-test-macro - 0.1.0
cargo-test-support - 0.1.0
cargo-util 0.2.3 0.2.4
crates-io 0.36.0 0.36.1
mdman 0.0.0 0.1.0
resolver-tests - 0.1.0
cargo 0.70.1 0.72.0
semver-check - 0.1.0
cargo-credential 0.1.0 0.2.0
cargo-credential-1password 0.1.0 0.2.0
cargo-credential-gnome-secret 0.1.0 0.2.0
cargo-credential-macos-keychain 0.1.0 0.2.0
cargo-credential-wincred 0.1.0 0.2.0
benchsuite - 0.1.0
```
After:
```console
name published current
==== ========= =======
cargo-platform 0.1.2 0.1.3
cargo-test-macro - 0.1.0
cargo-test-support - 0.1.0
cargo-util 0.2.3 0.2.4
crates-io 0.36.0 0.36.1
cargo 0.70.1 0.72.0
cargo-credential 0.1.0 0.2.0
cargo-credential-1password 0.1.0 0.2.0
cargo-credential-gnome-secret 0.1.0 0.2.0
cargo-credential-macos-keychain 0.1.0 0.2.0
cargo-credential-wincred 0.1.0 0.2.0
```
This is an alternative to `-Zminimal-versions` as discussed in #5657.
The problem with `-Zminimal-versions` is it requires the root most
dependencies to verify it and we then percolate that up the stack. This
requires a massive level of cooperation to accomplish and so far there
have been mixed results with it to the point that cargo's unstable
documentation discourages its use.
`-Zdirect-minimal-versions` instead only applies this rule to your
direct dependencies, allowing anyone in the stack to immediately adopt
it, independent of everyone else.
Special notes
- Living up to the name and the existing design, this ignores yanked
crates. This makes sense for `^1.1` version requirements but might
look weird for `^1.1.1` version requirements as it could select
`1.1.2`.
- This will error if an indirect dependency requires a newer version.
Your version requirement will need to capture what you use **and** all
of you dependencies. An alternative design would have tried to merge
the result of minimum versions for direct dependencies and maximum
versions for indirect dependencies. This would have been complex and
led to weird corner cases, making it harder to predict. I also suspect
the value gained would be relatively low as you can't verify that
version requirement in any other way.
- The error could be improved to call out that this was from minimal
versions but I felt getting this out now and starting to collect
feedback was more important.
There is a soundness issue with atty when building on Windows with a
custom allocator.
This PR switches direct dependencies on atty to is-terminal. New semver
compatible versions of clap and snapbox remove atty. #11417 upgrades
env_logger to remove it from there.
Fixes#11415
This concentrates all of the "prefer this version" logic previously
handled with `try_to_use` and `prefer_patch_deps` parameters into a
struct that hides both the reason a package version might be preferred
and the form that preference took (Dependency or PackageId). Besides
simplifying `RegistryQuerier::query` slightly, this invites further
refinements to version preferences to support new cargo features.
When selecting among several versions of a paackage, prefer versions
from `[patch]` sections over other versions, similar to how locked
versions are preferred.
Patches come in the form of a Dependency and not a PackageId, so this
preference is expressed with `prefer_patch_deps`, distinct from
`try_to_use`.
Split out cargo-util package for cargo-test-support.
This splits out code from `cargo` that was being used by `cargo-test-support` in order to remove the dev-dependency cycle on the `cargo` crate. The intent here is to improve development build times. On my system, `touch src/cargo/lib.rs ; cargo check --profile=test` goes from 6.4 seconds to 3.5. I suspect more substantial changes (more than just `touch`) should exhibit even more improvements.
This has a substantial downside that it is another package to manage publishing, particularly with making sure the version is updated correctly for crates.io. I'm uncertain if on balance it is worth it, but I lean towards moving forward with it.
`nightly_features_allowed()` is no longer doing any work, so it can be
accessed directly. This also renames the `enable_nightly_features` field
to `nightly_features_allowed`.
Previously, since `ENABLE_NIGHTLY_FEATURES` and
`NIGHTLY_FEATURES_ENABLED` were thread locals, reading them in any other
thread would always say nightly features were disabled. Now, they are
tied to the `Context` itself, so it is both more clear how the variables
are being set and fixes the behavior within work threads.
Note that `Context` is not thread-safe, so this passes a boolean through
to `BuildOutput::parse`.
reset lockfile information between resolutions
#8249 pointed out that some kind of lockfile data was leaking between calls to the resolver. @ehuss made a reproducing test case. This PR resets the `LockedMap` data structure when calling `register_previous_locks`.
lets see if CI likes it.
fix#8249
This stops using `to_string` as a proxy for this now-provided precise API.
This reverts commit b71927224fd9306b2b5bd2b4f8c22268eadfeb6a and bupms the
dependency version in Cargo.toml.
First reported in rust-lang/rust#65014 it looks like our error message
on cyclic dependencies may be confusing at times. It looks like this is
an issue because there are multiple paths through a graph for a
dependency, so using the generic `path_to_top` function isn't producing
the most useful path for this purpose.
We're already walking the graph though, so this commit adds an extra
parameter which collects the list of packages we've visited so far to
produce a hopefully always-accurate error message showing the chain of
dependencies end-to-end for what depends on what.
Resolver test/debug cleanup
This is several small things salvaged from abandoned PRs and implemented on top of #7011
In working on this I noted that the prop tests are very sensitive to whether backtrace are turned on. Maybe we should set that env to 0 for that builder?
These tests take a good amount of time to run locally and they're also
causing a lot of dependencies to get pulled into rust-lang/rust, so
let's have a separate crate that we just test on our own CI
