Generally, cargo avoids positional arguments. Mostly for the commands
that might forward arguments to another command, like `cargo test`.
It also allows some flexibility in turning flags into options.
For `cargo add` and `cargo remove`, we decided to accept positionals
because the motivations didn't seem to apply as much (similar to `cargo
install`).
This applies the pattern to `cargo update` as well which is in the same
category of commands as `cargo add` and `cargo remove`.
As for `--help` formatting, I'm mixed on whether `[SPEC]...` should be at the top like
other positionals or should be relegated to "Package selection". I went
with the latter mostly to make it easier to visualize the less common
choice.
Switching to a positional for `cargo update` (while keeping `-p` for
backwards compatibility) was referenced in #12425.
In addition to `foo:1.2.3`, we now support `foo@1.2.3` for pkgids. We
are also making it the default way of rendering pkgid's for the user.
With cargo-add in #10472, we've decided to only use `@` in it and to add
it as an alternative to `:` in the rest of cargo. `cargo-add`
originally used `@`. When preparing it for merge, I switched to `:` to
be consistent with pkgids. When discussing this, it was felt `@` has
precedence in too many tools to switch to `:` but that we should instead
switch pkgid's to use `@`, in a backwards compatible way.
See also https://internals.rust-lang.org/t/feedback-on-cargo-add-before-its-merged/16024/26?u=epage
When the user enables `--future-incompat-report`, we now display
a high-level summary of the problem, as well as several suggestions
for fixing the affected crates.
The command `cargo report future-incompatibilities` now takes
a `--crate` option, which can be used to display a report
(including the actual lint messages) for a single crate.
When this option is not used, we display the report for all
crates.
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.
