DESCRIPTION¶
This Cargo subcommand will automatically take rustc’s
suggestions from diagnostics like warnings and apply them to your source
code. This is intended to help automate tasks that rustc itself already
knows how to tell you to fix!
Executing cargo fix will under the hood execute
cargo-check(1). Any warnings applicable to your crate will be
automatically fixed (if possible) and all remaining warnings will be
displayed when the check process is finished. For example if you’d
like to apply all fixes to the current package, you can run:
which behaves the same as cargo check --all-targets.
cargo fix is only capable of fixing code that is normally
compiled with cargo check. If code is conditionally enabled with
optional features, you will need to enable those features for that code to
be analyzed:
Similarly, other cfg expressions like platform-specific
code will need to pass --target to fix code for the given target.
cargo fix --target x86_64-pc-windows-gnu
If you encounter any problems with cargo fix or otherwise
have any questions or feature requests please don’t hesitate to file
an issue at <https://github.com/rust-lang/cargo>.
Edition migration¶
The cargo fix subcommand can also be used to migrate a
package from one edition
<https://doc.rust-lang.org/edition-guide/editions/transitioning-an-existing-project-to-a-new-edition.html>
to the next. The general procedure is:
1.Run cargo fix --edition. Consider also using
the --all-features flag if your project has multiple features. You may
also want to run cargo fix --edition multiple times with different
--target flags if your project has platform-specific code gated by
cfg attributes.
3.Run your project tests to verify that everything still
works. If new warnings are issued, you may want to consider running cargo
fix again (without the --edition flag) to apply any suggestions
given by the compiler.
And hopefully that’s it! Just keep in mind of the caveats
mentioned above that cargo fix cannot update code for inactive
features or cfg expressions. Also, in some rare cases the compiler is
unable to automatically migrate all code to the new edition, and this may
require manual changes after building with the new edition.
OPTIONS¶
Fix options¶
--broken-code
Fix code even if it already has compiler errors. This is
useful if cargo fix fails to apply the changes. It will apply the
changes and leave the broken code in the working directory for you to inspect
and manually fix.
--edition
Apply changes that will update the code to the next
edition. This will not update the edition in the Cargo.toml manifest,
which must be updated manually after cargo fix --edition has
finished.
--edition-idioms
Apply suggestions that will update code to the preferred
style for the current edition.
--allow-no-vcs
Fix code even if a VCS was not detected.
--allow-dirty
Fix code even if the working directory has changes.
--allow-staged
Fix code even if the working directory has staged
changes.
Package Selection¶
By default, when no package selection options are given, the
packages selected depend on the selected manifest file (based on the current
working directory if --manifest-path is not given). If the manifest
is the root of a workspace then the workspaces default members are selected,
otherwise only the package defined by the manifest will be selected.
The default members of a workspace can be set explicitly with the
workspace.default-members key in the root manifest. If this is not
set, a virtual workspace will include all workspace members (equivalent to
passing --workspace), and a non-virtual workspace will include only
the root crate itself.
-p spec…, --package
spec…
Fix only the specified packages. See
cargo-pkgid(1) for the SPEC format. This flag may be specified multiple
times and supports common Unix glob patterns like
*,
? and
[]. However, to avoid your shell accidentally expanding glob patterns
before Cargo handles them, you must use single quotes or double quotes around
each pattern.
--workspace
Fix all members in the workspace.
--all
Deprecated alias for --workspace.
--exclude SPEC…
Exclude the specified packages. Must be used in
conjunction with the --workspace flag. This flag may be specified
multiple times and supports common Unix glob patterns like *, ?
and []. However, to avoid your shell accidentally expanding glob
patterns before Cargo handles them, you must use single quotes or double
quotes around each pattern.
Target Selection¶
When no target selection options are given, cargo fix will
fix all targets (--all-targets implied). Binaries are skipped if they
have required-features that are missing.
Passing target selection flags will fix only the specified
targets.
Note that --bin, --example, --test and
--bench flags also support common Unix glob patterns like *,
? and []. However, to avoid your shell accidentally expanding
glob patterns before Cargo handles them, you must use single quotes or
double quotes around each glob pattern.
--lib
Fix the package’s library.
--bin name…
Fix the specified binary. This flag may be specified
multiple times and supports common Unix glob patterns.
--bins
Fix all binary targets.
--example name…
Fix the specified example. This flag may be specified
multiple times and supports common Unix glob patterns.
--examples
Fix all example targets.
--test name…
Fix the specified integration test. This flag may be
specified multiple times and supports common Unix glob patterns.
--tests
Fix all targets in test mode that have the test =
true manifest flag set. By default this includes the library and binaries
built as unittests, and integration tests. Be aware that this will also build
any required dependencies, so the lib target may be built twice (once as a
unittest, and once as a dependency for binaries, integration tests, etc.).
Targets may be enabled or disabled by setting the test flag in the
manifest settings for the target.
--bench name…
Fix the specified benchmark. This flag may be specified
multiple times and supports common Unix glob patterns.
--benches
Fix all targets in benchmark mode that have the bench
= true manifest flag set. By default this includes the library and
binaries built as benchmarks, and bench targets. Be aware that this will also
build any required dependencies, so the lib target may be built twice (once as
a benchmark, and once as a dependency for binaries, benchmarks, etc.). Targets
may be enabled or disabled by setting the bench flag in the manifest
settings for the target.
--all-targets
Fix all targets. This is equivalent to specifying
--lib --bins --tests --benches --examples.
Feature Selection¶
The feature flags allow you to control which features are enabled.
When no feature options are given, the default feature is activated
for every selected package.
See the features documentation
<https://doc.rust-lang.org/cargo/reference/features.html#command-line-feature-options>
for more details.
-F features, --features features
Space or comma separated list of features to activate.
Features of workspace members may be enabled with
package-name/feature-name syntax. This flag may be specified multiple
times, which enables all specified features.
--all-features
Activate all available features of all selected
packages.
--no-default-features
Do not activate the default feature of the
selected packages.
Compilation Options¶
--target triple
Fix for the given architecture. The default is the host
architecture. The general format of the triple is
<arch><sub>-<vendor>-<sys>-<abi>. Run
rustc --print target-list for a list of supported targets. This flag
may be specified multiple times.
This may also be specified with the build.target config
value <https://doc.rust-lang.org/cargo/reference/config.html>.
Note that specifying this flag makes Cargo run in a different mode
where the target artifacts are placed in a separate directory. See the
build cache
<https://doc.rust-lang.org/cargo/reference/build-cache.html>
documentation for more details.
-r, --release
Fix optimized artifacts with the release profile.
See also the --profile option for choosing a specific profile by
name.
--profile name
--timings=fmts
Output information how long each compilation takes, and
track concurrency information over time. Accepts an optional comma-separated
list of output formats;
--timings without an argument will default to
--timings=html. Specifying an output format (rather than the default)
is unstable and requires
-Zunstable-options. Valid output formats:
•html (unstable, requires
-Zunstable-options): Write a human-readable file
cargo-timing.html to the target/cargo-timings directory with a
report of the compilation. Also write a report to the same directory with a
timestamp in the filename if you want to look at older runs. HTML output is
suitable for human consumption only, and does not provide machine-readable
timing data.
•json (unstable, requires
-Zunstable-options): Emit machine-readable JSON information about
timing information.
Output Options¶
--target-dir directory
Directory for all generated artifacts and intermediate
files. May also be specified with the
CARGO_TARGET_DIR environment
variable, or the
build.target-dir config value
<
https://doc.rust-lang.org/cargo/reference/config.html>. Defaults to
target in the root of the workspace.
Display Options¶
-v, --verbose
-q, --quiet
--color when
Control when colored output is used. Valid values:
•auto (default): Automatically detect if
color support is available on the terminal.
•always: Always display colors.
•never: Never display colors.
May also be specified with the term.color config
value <https://doc.rust-lang.org/cargo/reference/config.html>.
--message-format fmt
The output format for diagnostic messages. Can be
specified multiple times and consists of comma-separated values. Valid values:
•human (default): Display in a
human-readable text format. Conflicts with short and json.
•short: Emit shorter, human-readable text
messages. Conflicts with human and json.
•json-diagnostic-short: Ensure the
rendered field of JSON messages contains the “short”
rendering from rustc. Cannot be used with human or short.
•json-diagnostic-rendered-ansi: Ensure the
rendered field of JSON messages contains embedded ANSI color codes for
respecting rustc’s default color scheme. Cannot be used with
human or short.
•json-render-diagnostics: Instruct Cargo to
not include rustc diagnostics in JSON messages printed, but instead Cargo
itself should render the JSON diagnostics coming from rustc. Cargo’s
own JSON diagnostics and others coming from rustc are still emitted. Cannot be
used with human or short.
Manifest Options¶
--manifest-path path
Path to the Cargo.toml file. By default, Cargo
searches for the Cargo.toml file in the current directory or any parent
directory.
--ignore-rust-version
Ignore rust-version specification in
packages.
--locked
Asserts that the exact same dependencies and versions are
used as when the existing
Cargo.lock file was originally generated.
Cargo will exit with an error when either of the following scenarios arises:
•The lock file is missing.
•Cargo attempted to change the lock file due to a
different dependency resolution.
It may be used in environments where deterministic builds are
desired, such as in CI pipelines.
--offline
Prevents Cargo from accessing the network for any reason.
Without this flag, Cargo will stop with an error if it needs to access the
network and the network is not available. With this flag, Cargo will attempt
to proceed without the network if possible.
Beware that this may result in different dependency resolution
than online mode. Cargo will restrict itself to crates that are downloaded
locally, even if there might be a newer version as indicated in the local
copy of the index. See the cargo-fetch(1) command to download
dependencies before going offline.
May also be specified with the net.offline config
value <https://doc.rust-lang.org/cargo/reference/config.html>.
--frozen
Equivalent to specifying both --locked and
--offline.
--lockfile-path PATH
Changes the path of the lockfile from the default
(
<workspace_root>/Cargo.lock) to
PATH.
PATH must
end with
Cargo.lock (e.g.
--lockfile-path
/tmp/temporary-lockfile/Cargo.lock). Note that providing
--lockfile-path will ignore existing lockfile at the default path, and
instead will either use the lockfile from
PATH, or write a new lockfile
into the provided
PATH if it doesn’t exist. This flag can be
used to run most commands in read-only directories, writing lockfile into the
provided
PATH.
This option is only available on the nightly channel
<https://doc.rust-lang.org/book/appendix-07-nightly-rust.html> and
requires the -Z unstable-options flag to enable (see #14421
<https://github.com/rust-lang/cargo/issues/14421>).
Common Options¶
+toolchain
If Cargo has been installed with rustup, and the first
argument to
cargo begins with
+, it will be interpreted as a
rustup toolchain name (such as
+stable or
+nightly). See the
rustup documentation
<
https://rust-lang.github.io/rustup/overrides.html> for more information
about how toolchain overrides work.
--config KEY=VALUE or PATH
-C PATH
Changes the current working directory before executing
any specified operations. This affects things like where cargo looks by
default for the project manifest (
Cargo.toml), as well as the
directories searched for discovering
.cargo/config.toml, for example.
This option must appear before the command name, for example
cargo -C
path/to/my-project build.
This option is only available on the nightly channel
<https://doc.rust-lang.org/book/appendix-07-nightly-rust.html> and
requires the -Z unstable-options flag to enable (see #10098
<https://github.com/rust-lang/cargo/issues/10098>).
-h, --help
Prints help information.
-Z flag
Unstable (nightly-only) flags to Cargo. Run cargo -Z
help for details.
Miscellaneous Options¶
-j N, --jobs N
Number of parallel jobs to run. May also be specified
with the
build.jobs config value
<
https://doc.rust-lang.org/cargo/reference/config.html>. Defaults to the
number of logical CPUs. If negative, it sets the maximum number of parallel
jobs to the number of logical CPUs plus provided value. If a string
default is provided, it sets the value back to defaults. Should not be
0.
--keep-going
Build as many crates in the dependency graph as possible,
rather than aborting the build on the first one that fails to build.
For example if the current package depends on dependencies
fails and works, one of which fails to build, cargo fix
-j1 may or may not build the one that succeeds (depending on which one
of the two builds Cargo picked to run first), whereas cargo fix -j1
--keep-going would definitely run both builds, even if the one run first
fails.