This adds a set of tests which validates various edge cases around how
`cargo fix` works in terms of calling `rustc` multiple times. This uses
a replacement of `rustc` so it doesn't depend on the behavior of rustc
itself which is not always stable.
This adds a garbage collector which will remove old files from cargo's
global cache.
A general overview of the changes here:
- `cargo::core::global_cache_tracker` contains the `GlobalCacheTracker`
which handles the interface to a sqlite database which stores
timestamps of the last time a file was used.
- `DeferredGlobalLastUse` is a type that implements an optimization for
collecting last-use timestamps so that they can be flushed to disk all
at once.
- `cargo::core::gc` contains the `Gc` type which is the interface for
performing garbage collection. It coordinates with the
`GlobalCacheTracker` for determining what to delete.
- Garbage collection can either be automatic or manual. The automatic
garbage collection supports some config options for defining when
it runs and how much it deletes.
- Manual garbage collection can be performed via options to `cargo
clean`.
- `cargo clean` uses the new package cache locking system to coordinate
access to the package cache to prevent interference with other cargo
commands running concurrently.
This introduces a new `CacheLocker` which manages locks on the package
cache. Instead of either being "locked" or "not locked", the new locker
supports multiple modes:
- Shared lock: Cargo can read from the package sources, along with any
other cargos reading at the same time.
- Download exclusive lock: Only one cargo can perform downloads.
Download locks do not interfere with Shared locks, since it is
expected that downloading does not modify existing files (only adds
new ones).
- Mutate exclusive lock: Only one cargo can have this lock, and it also
prevents shared locks. This is so that the cargo can modify the
package cache (such as deleting files) without breaking concurrent
processes.
Currently, the UI tests are
- `cargo add`
- `cargo new`
- `cargo remove`
- `init`
One of these is not like the others. This change renames `init` to
`cargo_init` to suggest it is the UI tests for the `cargo init` command,
rather than `init` functionality.
feat(resolver): `-Zdirect-minimal-versions`
This is an alternative to `-Zminimal-versions` as discussed in #5657.
Problems with `-Zminimal-versions` includes
- 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.
- Users expect `cargo check -Zminimal-versions` to force resolving to minimal but it doesn't as the default maximal resolve is compatible and requires `cargo update -Zminimal-versions`
- Different compatible versions might be selected, breaking interop between crates, changing feature unification, and breaking `-sys` crates without bad `links`
`-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.
- This also means discrepancies between `dependencies` and `dev-dependencies` are errors
- 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.
One advantage of this approach over `-Zminimal-versions` is that it removes most of the problems that [cargo-minimal-versions](https://github.com/taiki-e/cargo-minimal-versions) tried to workaround.
As for the implementation, this might not be the most elegant solution but it works and we can always iterate and improve on it in the future.
- We keep the state as a `bool` throughout but compensate for that by explicitly creating a variable to abstract away constants
- The name changes depending on the context, from `direct_minimal_version` when dealing with the unstable flag to `first_minimal_version` when the concept of "direct" is lost to `first_version` when we split off the ordering concept into a separate variable
- Packages that respect `direct_minimal_versions` are determined by whether they are the top-level `summaries` that get past into `resolve`
### What does this PR try to resolve?
The primary use case is verifying version requirements to avoid depending on something newer than might be available in a dependent
For this to help the MSRV use case, the crate author must directly depend on all indirect dependencies where their latest release has too new of an MSRV but at least they can do so with the `^` operator, rather than `<` and breaking the ecosystem.
### How should we test and review this PR?
The first two commits add tests using `-Zminimal-versions`. The commit that adds `-Zdirect-minimal-versions` updates the tests, highlighting the differences in behavior.
### Additional information
Potential areas of conversation for stablization
- Flag name
- Handling of yanked (pick first non-yanked, pick yanked, error)
- Quality of error message
- Should the package have a "memory" of this flag being set by writing it to the lockfile?
Potential future work
- Stablize this
- Remove `-Zminimal-versions`
- Update `cargo publish`s `--verify` step to use this.
- The challenge is this won't be using the packaged `Cargo.lock` which probably should also be verified.
Change rustdoc-scrape-examples to be a target-level configuration
This PR addresses issues raised in rust-lang/cargo#9525. Specifically:
1. It enables examples to be scraped from `#[test]` functions, by passing additional flags to Rustdoc to ensure that these functions aren't ignored by rustc.
2. It moves the `arg` from `-Z rustdoc-scrape-examples={arg}` into a target-level configuration that can be added to Cargo.toml.
The added test `scrape_examples_configure_target` shows a concrete example. In short, examples will be default scraped from Example and Lib targets. Then the user can enable or disable scraping like so:
```toml
[lib]
doc-scrape-examples = false
[[test]]
name = "my_test"
doc-scrape-examples = true
```
Tracking issue: https://github.com/rust-lang/cargo/issues/9096
Original PR: https://github.com/rust-lang/cargo/pull/9992
Add 'bindeps' -Z flag for later use
A test to validate artifact dependencies aren't currently parsed.
Parse 'artifact' and 'lib' fields.
Note that this isn't behind a feature toggle so 'unused' messages will
disappear.
Transfer artifact dependencies from toml- into manifest-dependencies
There are a few premises governing the operation.
- if unstable features are not set, warn when 'artifact' or 'lib' is
encountered.
- bail if 'lib' is encountered alone, but warn that this WOULD happen
with nightly.
- artifact parsing checks for all invariants, but some aren't tested.
Assure serialization of 'artifact' and 'lib' fields produces suitable values during publishing
This should be the only place were these fields matter and where a cargo
manifest is actually produced. These are only for internal use, no user
is typically going to see or edit them.
Place all artifact dependency tests inta their own module
This facilitates deduplication later and possibly redistribution into
other modules if there is a better fit.
Represent artifacts that are rust libraries as another ArtifactKind
This is more consistent and probably simpler for later use.
No need to reflect the TOML data structure.
Add tests to assure only 'lib = true' artifact deps are documented
RFC-3028 doesn't talk about documentation, but for lib=true it's clear
what the desired behaviour should be.
If an artifact isn't a library though, then for now, it's transparent,
maybe.
Many more tests, more documentation, mild `Artifact` refactor
The latter seems to be a better fit for what being an artifact
really means within cargo, as it literally turns being a library
on or off, and thus only optionally becoming a normal library.
refactor to prepare for artifact related checks
Don't show a no-lib warning for artifact dependencies (with lib = false)
Tests for more artifact dependency invariants
These are merely a proof of concept to show that we are not in
a position to actually figure out everything about artifacts
right after resolution.
However, the error message looks more like a fatal error and less
like something that can happen with a more elaborate error message
with causes.
This might show that these kind of checks might be better done later
right before trying to use the information for create compile units.
Validate that artifact deps with lib=true still trigger no-lib warnings
This triggers the same warning as before, for now without any
customization to indicate it's an artifact dependency.
Use warnings instead of errors
------------------------------
This avoids the kind of harsh end of compilation in favor of something
that can be recovered from. Since warnings are annoying, users will
probably avoid re-declaring artifact dependencies.
Hook in artifact dependencies into build script runs
Even though we would still have to see what happens if they have a lib
as well. Is it built twice?
Also
----
- fly-by refactor: fix typo; use ? in method returning option
- Propagate artifact information into Units; put artifacts into place
This means artifacts now have their own place in the 'artifact'
directory and uplifts won't happen for them.
- refactor and fix cippy suggestion
- fix build after rebasing onto master
Create directories when executing the job, and not when preparing it.
also: Get CI to work on windows the easy way, for now.
Set directories for artifact dependencies in build script runtimes
Test remaining kinds of build-script runtime environment variables
Also
----
- Fix windows tests, the quick way.
- Try to fix windows assertions, and generalize them
- Fix second test for windows, hopefully
test for available library dependency in build scripts with lib = true
probably generally exclude all artifact dependencies with lib=false.
Pass renamed dep names along with unit deps to allow proper artifact env names
Test for selective bin:<name> syntax, as well as binaries with dashes
Test to assure dependency names are transformed correctly
assure advertised binaries and directories are actually present
This wouldn't be the case if dependencies are not setup correctly,
for instance.
Also
----
- make it easier to see actual values even on failure
This should help figure out why on CI something fails that works
locally no matter what.
Turns out this is a race condition, with my machine being on the good
side of it so it doesn't show in testing. Fortunately it still can be
reproduced and easily tested for.
- refactor test; the race condition is still present though
- Force CI to pass here by avoiding checks triggering race.
- Fix windows build, maybe?
More tolerant is_file() checks to account for delay on CI
This _should_ help CI to test for the presence which is better than
not testing at all.
This appears to be needed as the output file isn't ready/present in time
for some reason.
The root cause of this issue is unknown, but it's definitely a race
as it rarely happens locally. When it happened, the file was always
present after the run.
Now we will learn if it is truly not present, ever, or if it's maybe
something very else.
Validate libs also don't see artifact dependencies as libraries with lib=false
Also
----
- Add prelimiary test for validating build-time artifacts
- Try to fix CI on gnu windows
Which apparently generates paths similar to linux, but with .exe suffix.
The current linux patterns should match that.
- refactor
Help sharing code across modules
allow rustc to use artifact dep environment variables, but…
…it needs some adjustments to actually setup the unit dependency graph
with artifacts as well.
Right now it will only setup dependencies for artifacts that are libs,
but not the artifacts themselves, completely ignoring them when they
are not libs.
Make artifact dependencies available in main loop
This is the commit message #2:
------------------------------
rough cut of support for artifact dependencies at build time…
…which unfortunately already shows that the binary it is supposed to
include is reproducibly not ready in time even though the path is
correct and it's present right after the run.
Could it be related to rmeta?
This is the commit message #3:
------------------------------
Fix test expectations as failure is typical than the warning we had before…
…and add some tolerance to existing test to avoid occasional failures.
This doesn't change the issue that it also doens't work at all for
libraries, which is nicely reproducable and hopefully helps to fix
this issue.
This is the commit message #4:
------------------------------
Probably the fix for the dependency issue in the scheduler
This means that bin() targets are now properly added to the job graph
to cause proper syncing, whereas previously apparently it would
still schedule binaries, but somehow consider them rmeta and thus
start their dependents too early, leading to races.
This is the commit message #5:
------------------------------
Don't accidentally include non-gnu windows tests in gnu windows.
Support cargo doc and cargo check
The major changes here are…
- always compile artifacts in build mode, as we literally want the
build output, always, which the dependent might rely on being present.
- share code between the rather similar looking paths for rustdoc and
rustc.
Make artifact messages appear more in line with cargo by using backticks
Also: Add first test for static lib support in build scripts
build-scripts with support for cdylib and staticlib
- Fix windows msvc build
No need to speculate why the staticlib has hashes in the name even
though nothing else.
staticlib and cdylib support for libraries
test staticlib and cdylibs for rustdoc as well.
Also catch a seemingly untested special case/warning about the lack
of linkable items, which probably shouldn't be an issue for artifacts
as they are not linkable in the traditional sense.
more useful test for 'cargo check'
`cargo check` isn't used very consistently in tests, so when we use it
we should be sure to actually try to use an artifact based feature
to gain some coverage.
verify that multiple versions are allowed for artifact deps as well.
also: remove redundant test
This is the commit message #2:
------------------------------
Properly choose which dependencies take part in artifact handling
Previously it would include them very generously without considering
the compatible dependency types.
This is the commit message #3:
------------------------------
a more complex test which includes dev-dependencies
It also shows that doc-tests don't yet work as rustdoc is run outside of
the system into which we integrate right now.
It should be possible to write our environment variable configuration
in terms of this 'finished compilation' though, hopefully with
most code reused.
This is the commit message #4:
------------------------------
A first stab at storing artifact environment variables for packages…
…however, it seems like the key for this isn't necessarily correct
under all circumstances. Maybe it should be something more specific,
don't know.
This is the commit message #5:
------------------------------
Adjust key for identifying units to Metadata
This one is actually unique and feels much better.
This is the commit message #6:
------------------------------
Attempt to make use of artifact environment information…
…but fail as the metadata won't match as the doctest unit is, of course,
its separate unit. Now I wonder if its possible to find the artifact
units in question that have the metadata.
Properly use metadata to use artifact environment variables in doctests
This is the commit message #2:
------------------------------
Add test for resolver = "2" and build dependencies
Interestingly the 'host-features' flag must be set (as is seemingly
documented in the flags documentation as well), even though I am not
quite sure if this is the 100% correct solution. Should it rather
have an entry with this flag being false in its map? Probably not…
but I am not quite certain.
This is the commit message #3:
------------------------------
set most if not all tests to use resolver = "2"
This allows to keep it working with the most recent version while
allowing to quickly test with "1" as well (which thus far was working
fine).
All tests I could imagine (excluding target and profiles) are working now
Crossplatform tests now run on architecture aarm64 as well.
More stringent negative testing
Fix incorrect handling of dependency directory computation
Previously it would just 'hack' the deps-dir to become something very
different for artifacts.
This could easily be fixed by putting the logic for artifact output
directories into the right spot.
A test for cargo-tree to indicate artifacts aren't handled specifically
Assure build-scripts can't access artifacts at build time
Actual doc-tests with access to artifact env vars
All relevant parsing of `target = [..]`
Next step is to actually take it into consideration.
A failing test for adjusting the target for build script artifacts using --target
Check for unknown artifact target triple in a place that exists for a year
The first test showing that `target="target"` deps seemingly work
For now only tested for build scripts, but it won't be much different
for non-build dependencies.
build scripts accept custom targets unconditionally
Support target setting for non-build dependencies
This is the commit message #2:
------------------------------
Add doc-test cross compile related test
Even though there is no artifact code specific to doc testing, it's
worth to try testing it with different target settings to validate
it still works despite doc tests having some special caseing around
target settings.
This is the commit message #3:
------------------------------
A test to validate profiles work as expected for build-deps and non-build deps
No change is required to make this work and artifact dependencies 'just work'
based on the typical rules of their non-artifact counterarts.
This is the commit message #4:
------------------------------
Adjust `cargo metadata` to deal with artifact dependencies
This commit was squashed and there is probably more that changed.
This is the commit message #5:
------------------------------
Show bin-only artifacts in "resolve" of metadata as well.
This is the commit message #6:
------------------------------
minor refactoring during research for RFC-3176
This will soon need to return multiple extern-name/dep-name pairs.
This is the commit message #7:
------------------------------
See if opt-level 3 works on win-msvc in basic profile test for artifacts
This is the same value as is used in the other test of the same name,
which certainly runs on windows.
This is the commit message #8:
------------------------------
refactor
Assure the type for targets reflect that they cannot be the host target,
which removes a few unreachable!() expressions.
Put `root_unit_compile_kind` into `UnitFor`
Previously that wasn't done because of the unused `all_values()`
method which has now been deleted as its not being used anyomre.
This allows for the root unit compile kind to be passed as originally
intended, instead of working around the previous lack of extendability
of UnitFor due to ::all_values().
This is also the basis for better/correct feature handling once
feature resolution can be depending on the artifact target as well,
resulting in another extension to UnitFor for that matter.
Also
----
- Fix ordering
Previously the re-created target_mode was used due to the reordering
in code, and who knows what kind of effects that might have
(despite the test suite being OK with it).
Let's put it back in place.
- Deactivate test with filename collision on MSVC until RFC-3176 lands
Avoid clashes with binaries called 'artifact' by putting 'artifact/' into './deps/'
This commit addresses review comment https://github.com/rust-lang/cargo/pull/9992#discussion_r772939834
Don't rely on operator precedence for boolean operations
Now it should be clear that no matter what the first term is,
if the unit is an artifact, we should enqueue it.
Replace boolean and `/*artifact*/ <bool>` with `IsArtifact::(Yes/No)`
fix `doc::doc_lib_false()` test
It broke due to major breakage in the way dependencies are calculated.
Now we differentiate between deps computation for docs and for building.
Avoid testing for doctest cross-compilation message
It seems to be present on my machine, but isn't on linux and it's
probably better to leave it out entirely and focus on the portions
of consecutive output that we want to see at least.
A test to validate features are unified across libraries and those in artifact deps in the same target
Allow aarch64 MacOS to crosscompile to an easily executable alternative target
That way more tests can run locally.
Support for feature resolution per target
The implementation is taken directly from RFC-3176 and notably lacks
the 'multidep' part.
Doing this definitely has the benefit of making entirely clear
'what is what' and helps to greatly reduce the scope of RFC-3176
when it's rebuilt based on the latest RF-3028, what we are implementing
right now.
Also
----
- A test which prooves that artifact deps with different target don't have a feature namespace yet
- Add a test to validate features are namespaced by target
Previously it didn't work because it relies on resolver = "2".
- 'cargo metadata' test to see how artifact-deps are presented
- Missed an opportunity for using the newly introduced `PackageFeaturesKey`
- Use a HashMap to store name->value relations for artifact environment variables
This is semantically closer to what's intended.
also: Remove a by now misleading comment
Prevent resolver crash if `target = "target"` is encountered in non-build dependencies
A warning was emitted before, now we also apply a fix.
Previously the test didn't fail as it accidentally used the old
resolver, which now has been removed.
Abort in parsing stage if nightly flag is not set and 'artifact' is used
There is no good reason to delay errors to a later stage when code
tries to use artifacts via environment variables which are not present.
Change wording of warning message into what's expected for an error message
remove unnecessary `Result` in `collect()` call
Improve logic to warn if dependencie are ignored due to missing libraries
The improvement here is to trigger correctly if any dependency of a
crate is potentially a library, without having an actual library target
as part of the package specification.
Due to artifact dependencies it's also possible to have a dependency
to the same crate of the same version, hence the package name
isn't necessarily a unique name anymore. Now the name of the actual
dependency in the toml file is used to alleviate this.
Various small changes for readability and consistency
A failing test to validate artifacts work in published crates as well
Originally this should have been a test to see target acquisition works
but this more pressing issue surfaced instead.
Make artifacts known to the registry data (backwards compatible)
Now artifacts are serialized into the registry on publish (at least
if this code is actually used in the real crates-io registry) which
allows the resolve stage to contain artifact information.
This seems to be in line with the idea to provide cargo with all
information it needs to do package resolution without downloading
the actual manifest.
Pick up all artifact targets into target info once resolve data is available
Even though this works in the test at hand, it clearly shows there
is a cyclic dependency between the resolve and the target data.
In theory, one would have to repeat resolution until it settles
while avoiding cycles.
Maybe there is a better way.
Add `bindeps`/artifact dependencies to `unstsable.md` with examples
Fix tests
Various small improvements
Greatly simplify artifact environment propagation to commands
Remove all adjustments to cargo-metadata, but leave tests
The tests are to record the status quo with the current code
when artifact dependencies are present and assure the information
is not entirely non-sensical.
Revert "Make artifacts known to the registry data (backwards compatible)"
This reverts commit adc5f8ad04840af9fd06c964cfcdffb8c30769b0.
Ideally we are able to make it work without altering the registry
storage format. This could work if information from the package
set is added to the resolve information.
Enrich resolves information with additional information from downloaded manifests
Resolve information comes from the registry, and it's only as rich as
needed to know which packages take part in the build.
Artifacts, however, don't influence dependency resolution, hence it
shouldn't be part of it.
For artifact information being present nonetheless when it matters,
we port it back to the resolve graph where it will be needed later.
Collect 'forced-target' information from non-workspace members as well
This is needed as these targets aren't present in the registry and
thus can't be picked up by traversing non-workspce members.
The mechanism used to pick up artifact targets can also be used
to pick up these targets.
Remove unnecessary adjustment of doc test
refactor `State::deps()` to have filter; re-enable accidentally disabled test
The initial rebasing started out with a separted `deps_filtered()`
method to retain the original capabilities while minimizing the chance
for surprises. It turned out that the all changes combined in this PR
make heavy use of filtering capabilities to the point where
`deps(<without filter>)` was unused. This suggested that it's required
to keep it as is without a way to inline portions of it.
For the original change that triggered this rebase, see
bd45ac81ba
The fix originally made was reapplied by allowing to re-use the
required filter, but without inlining it.
Always error on invalid artifact setup, with or without enabled bindeps feature
Clarify how critical resolver code around artifact is working
Remove workaround in favor of deferring a proper implementation
See https://github.com/rust-lang/cargo/pull/9992#issuecomment-1033394197
for reference and the TODO in the ignored test for more information.
truncate comments at 80-90c; cleanup
- remove unused method
- remove '-Z unstable-options'
- improve error message
- improve the way MSVC special cases are targetted in tests
- improve how executables are found on non MSVC
Avoid depending on output of rustc
There is cyclic dependency between rustc and cargo which makes it
impossible to adjust cargo's expectations on rustc without leaving
broken commits in rustc and cargo.
Add missing documentation
fix incorrect removal of non-artifact libs
This is also the first step towards cleaning up the filtering logic
which is still making some logic harder to understand than needs be.
The goal is to get it to be closer to what's currently on master.
Another test was added to have more safety regarding the overall
library inclusion logic.
inline `build_artifact_requirements_to_units()`
Simplify filtering
This adds a default filter to `state.deps(…)` making it similar to
what's currently in master, while creating another version of it
to allow setting a custom filter. This is needed as the default filter
won't allow build dependencies, which we need in this particular case.
`calc_artifact_deps(…)` now hard-codes the default filter which is
needed due to the use of `any` here:
c0e6abe384/src/cargo/core/compiler/unit_dependencies.rs (L1119)
.
Simplify filtering.
cc rust-lang/rust#71249
This implements the Cargo side of 'Cargo report future-incompat'
Based on feedback from alexcrichton and est31, I'm implemented this a
flag `--future-compat-report` on `cargo check/build/rustc`, rather than
a separate `cargo describe-future-incompatibilities` command. This
allows us to avoid writing additional information to disk (beyond the
pre-existing recording of rustc command outputs).
This PR contains:
* Gating of all functionality behind `-Z report-future-incompat`.
Without this flag, all user output is unchanged.
* Passing `-Z emit-future-incompat-report` to rustc when
`-Z report-future-incompat` is enabled
* Parsing the rustc JSON future incompat report, and displaying it
it a user-readable format.
* Emitting a warning at the end of a build if any crates had
future-incompat reports
* A `--future-incompat-report` flag, which shows the full report for
each affected crate.
* Tests for all of the above.
At the moment, we can use the `array_into_iter` to write a test.
However, we might eventually get to a point where rustc is not currently
emitting future-incompat reports for any lints. What would we want the
cargo tests to do in this situation?
This functionality didn't require any significant internal changes to
Cargo, with one exception: we now process captured command output for
all units, not just ones where we want to display warnings. This may
result in a slightly longer time to run `cargo build/check/rustc` from
a full cache. since we do slightly more work for each upstream
dependency. Doing this seems unavoidable with the current architecture,
since we need to process captured command outputs to detect
any future-incompat-report messages that were emitted.
Add support for [env] section in .cargo/config.toml
This adds support for an `[env]` section in the config.toml files. Environment variables set in this section will be applied to the environment of any processes executed by cargo.
This is implemented to follow the recommendations in https://github.com/rust-lang/cargo/pull/8839#issuecomment-725678657
Variables have optional `force` and `relative` flags. `force` means the variable can override an existing environment variable. `relative` means the variable represents a path relative to the location of the directory that contains the `.cargo/` directory that contains the `config.toml` file. A relative variable will have an absolute path prepended to it before setting it in the environment.
```
[env]
FOOBAR = "Apple"
PATH_TO_SOME_TOOL = { value = "bin/tool", relative = true }
USERNAME = { value = "test_user", force = true }
```
Fixes#4121
This adds support for an `[env]` section in the config.toml files. Environment variables set in this section will be applied to the environment of any processes executed by cargo.
```
[env]
FOOBAR = "Apple"
PATH_TO_SOME_TOOL = { value = "bin/tool", relative = true }
USERNAME = { value = "test_user", force = true }
```
List available packages if providing `--package` with an empty value
May resolves#8591
## How
First we need to take the responsibility of check command line arguments from claps. I've examine all 10 build commands and all of them call [`ArgMatchesExt::compile_options`](2f115a76e5/src/cargo/util/command_prelude.rs (L389-L395)) directly or indirectly. And `compile_options` [calls `check_optional_opts`](2f115a76e5/src/cargo/util/command_prelude.rs (L499-L501)) to check if target selection options given an empty value. So we can do the same logic there.
I've also add a error message for an edge case though that one would never trigger at this moment.
