Auto merge of #12078 - cassaundra:cargo-add-rust-version, r=epage

Consider rust-version when selecting packages for cargo add

When `-Zmsrv-policy` is enabled, try to select dependencies which satisfy the target package's `rust-version` field (if present). If the selected version is not also the latest, emit a warning to the user about this discrepancy.

Dependency versions without a `rust-version` are considered compatible by default.

One remaining question is whether we should go into more detail when explaining the discrepancy and ways to resolve it to the user. For example:

```
warning: selecting older version of `fancy-dep` to satisfy the minimum supported rust version
note: version 0.1.2 of `fancy-dep` has an MSRV of 1.72, which is greater than this package's MSRV of 1.69
```

Implements #10653.

r? `@epage`

src/bin/cargo/commands/add.rs

@@ -72,6 +72,10 @@ The package will be removed from your features.")
 Example uses:
 - Depending on multiple versions of a crate
 - Depend on crates with the same name from different registries"),
+ flag(
+ "ignore-rust-version",
+ "Ignore `rust-version` specification in packages (unstable)"
+ ),
  ])
  .arg_manifest_path()
  .arg_package("Package to modify")
@@ -188,12 +192,24 @@ pub fn exec(config: &mut Config, args: &ArgMatches) -> CliResult {
 
  let dependencies = parse_dependencies(config, args)?;
 
+ let ignore_rust_version = args.flag("ignore-rust-version");
+ if ignore_rust_version && !config.cli_unstable().msrv_policy {
+ return Err(CliError::new(
+ anyhow::format_err!(
+ "`--ignore-rust-version` is unstable; pass `-Zmsrv-policy` to enable support for it"
+ ),
+ 101,
+ ));
+ }
+ let honor_rust_version = !ignore_rust_version;
+
  let options = AddOptions {
  config,
  spec,
  dependencies,
  section,
  dry_run,
+ honor_rust_version,
  };
  add(&ws, &options)?;
 

src/cargo/ops/cargo_add/mod.rs

@@ -51,6 +51,8 @@ pub struct AddOptions<'a> {
  pub section: DepTable,
  /// Act as if dependencies will be added
  pub dry_run: bool,
+ /// Whether the minimum supported Rust version should be considered during resolution
+ pub honor_rust_version: bool,
 }
 
 /// Add dependencies to a manifest
@@ -86,7 +88,9 @@ pub fn add(workspace: &Workspace<'_>, options: &AddOptions<'_>) -> CargoResult<(
  &manifest,
  raw,
  workspace,
+ &options.spec,
  &options.section,
+ options.honor_rust_version,
  options.config,
  &mut registry,
  )
@@ -256,7 +260,9 @@ fn resolve_dependency(
  manifest: &LocalManifest,
  arg: &DepOp,
  ws: &Workspace<'_>,
+ spec: &Package,
  section: &DepTable,
+ honor_rust_version: bool,
  config: &Config,
  registry: &mut PackageRegistry<'_>,
 ) -> CargoResult<DependencyUI> {
@@ -368,7 +374,14 @@ fn resolve_dependency(
  }
  dependency = dependency.set_source(src);
  } else {
- let latest = get_latest_dependency(&dependency, false, config, registry)?;
+ let latest = get_latest_dependency(
+ spec,
+ &dependency,
+ false,
+ honor_rust_version,
+ config,
+ registry,
+ )?;
 
  if dependency.name != latest.name {
  config.shell().warn(format!(
@@ -518,8 +531,10 @@ fn get_existing_dependency(
 }
 
 fn get_latest_dependency(
+ spec: &Package,
  dependency: &Dependency,
  _flag_allow_prerelease: bool,
+ honor_rust_version: bool,
  config: &Config,
  registry: &mut PackageRegistry<'_>,
 ) -> CargoResult<Dependency> {
@@ -529,27 +544,87 @@ fn get_latest_dependency(
  unreachable!("registry dependencies required, found a workspace dependency");
  }
  MaybeWorkspace::Other(query) => {
- let possibilities = loop {
+ let mut possibilities = loop {
  match registry.query_vec(&query, QueryKind::Fuzzy) {
  std::task::Poll::Ready(res) => {
  break res?;
  }
  std::task::Poll::Pending => registry.block_until_ready()?,
  }
  };
- let latest = possibilities
- .iter()
- .max_by_key(|s| {
- // Fallback to a pre-release if no official release is available by sorting them as
- // less.
- let stable = s.version().pre.is_empty();
- (stable, s.version())
- })
- .ok_or_else(|| {
- anyhow::format_err!(
- "the crate `{dependency}` could not be found in registry index."
- )
- })?;
+
+ possibilities.sort_by_key(|s| {
+ // Fallback to a pre-release if no official release is available by sorting them as
+ // less.
+ let stable = s.version().pre.is_empty();
+ (stable, s.version().clone())
+ });
+
+ let mut latest = possibilities.last().ok_or_else(|| {
+ anyhow::format_err!(
+ "the crate `{dependency}` could not be found in registry index."
+ )
+ })?;
+
+ if config.cli_unstable().msrv_policy && honor_rust_version {
+ fn parse_msrv(rust_version: impl AsRef<str>) -> (u64, u64, u64) {
+ // HACK: `rust-version` is a subset of the `VersionReq` syntax that only ever
+ // has one comparator with a required minor and optional patch, and uses no
+ // other features. If in the future this syntax is expanded, this code will need
+ // to be updated.
+ let version_req = semver::VersionReq::parse(rust_version.as_ref()).unwrap();
+ assert!(version_req.comparators.len() == 1);
+ let comp = &version_req.comparators[0];
+ assert_eq!(comp.op, semver::Op::Caret);
+ assert_eq!(comp.pre, semver::Prerelease::EMPTY);
+ (comp.major, comp.minor.unwrap_or(0), comp.patch.unwrap_or(0))
+ }
+
+ if let Some(req_msrv) = spec.rust_version().map(parse_msrv) {
+ let msrvs = possibilities
+ .iter()
+ .map(|s| (s, s.rust_version().map(parse_msrv)))
+ .collect::<Vec<_>>();
+
+ // Find the latest version of the dep which has a compatible rust-version. To
+ // determine whether or not one rust-version is compatible with another, we
+ // compare the lowest possible versions they could represent, and treat
+ // candidates without a rust-version as compatible by default.
+ let (latest_msrv, _) = msrvs
+ .iter()
+ .filter(|(_, v)| v.map(|msrv| req_msrv >= msrv).unwrap_or(true))
+ .last()
+ .ok_or_else(|| {
+ // Failing that, try to find the highest version with the lowest
+ // rust-version to report to the user.
+ let lowest_candidate = msrvs
+ .iter()
+ .min_set_by_key(|(_, v)| v)
+ .iter()
+ .map(|(s, _)| s)
+ .max_by_key(|s| s.version());
+ rust_version_incompat_error(
+ &dependency.name,
+ spec.rust_version().unwrap(),
+ lowest_candidate.copied(),
+ )
+ })?;
+
+ if latest_msrv.version() < latest.version() {
+ config.shell().warn(format_args!(
+ "ignoring `{dependency}@{latest_version}` (which has a rust-version of \
+ {latest_rust_version}) to satisfy this package's rust-version of \
+ {rust_version} (use `--ignore-rust-version` to override)",
+ latest_version = latest.version(),
+ latest_rust_version = latest.rust_version().unwrap(),
+ rust_version = spec.rust_version().unwrap(),
+ ))?;
+
+ latest = latest_msrv;
+ }
+ }
+ }
+
  let mut dep = Dependency::from(latest);
  if let Some(reg_name) = dependency.registry.as_deref() {
  dep = dep.set_registry(reg_name);
@@ -559,6 +634,31 @@ fn get_latest_dependency(
  }
 }
 
+fn rust_version_incompat_error(
+ dep: &str,
+ rust_version: &str,
+ lowest_rust_version: Option<&Summary>,
+) -> anyhow::Error {
+ let mut error_msg = format!(
+ "could not find version of crate `{dep}` that satisfies this package's rust-version of \
+ {rust_version}\n\
+ help: use `--ignore-rust-version` to override this behavior"
+ );
+
+ if let Some(lowest) = lowest_rust_version {
+ // rust-version must be present for this candidate since it would have been selected as
+ // compatible previously if it weren't.
+ let version = lowest.version();
+ let rust_version = lowest.rust_version().unwrap();
+ error_msg.push_str(&format!(
+ "\nnote: the lowest rust-version available for `{dep}` is {rust_version}, used in \
+ version {version}"
+ ));
+ }
+
+ anyhow::format_err!(error_msg)
+}
+
 fn select_package(
  dependency: &Dependency,
  config: &Config,

src/doc/man/cargo-add.md

@@ -123,6 +123,15 @@ crates, the features for a specific crate may be enabled with
 which enables all specified features.
 {{/option}}
 
+{{#option "`--ignore-rust-version`" }}
+Ignore `rust-version` specification in packages.
+
+This option is unstable and available only 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 <https://github.com/rust-lang/cargo/issues/5579> for more information.
+{{/option}}
+
 {{/options}}
 
 

src/doc/man/generated_txt/cargo-add.txt

@@ -111,6 +111,15 @@ OPTIONS
  be enabled with package-name/feature-name syntax. This flag may be
  specified multiple times, which enables all specified features.
 
+ --ignore-rust-version
+ Ignore rust-version specification in packages.
+
+ This option is unstable and available only 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
+ <https://github.com/rust-lang/cargo/issues/5579> for more
+ information.
+
  Display Options
  -v, --verbose
  Use verbose output. May be specified twice for “very verbose”

src/doc/src/commands/cargo-add.md

@@ -129,6 +129,14 @@ crates, the features for a specific crate may be enabled with
 which enables all specified features.</dd>
 
 
+<dt class="option-term" id="option-cargo-add---ignore-rust-version"><a class="option-anchor" href="#option-cargo-add---ignore-rust-version"></a><code>--ignore-rust-version</code></dt>
+<dd class="option-desc">Ignore <code>rust-version</code> specification in packages.</p>
+<p>This option is unstable and available only on the
+<a href="https://doc.rust-lang.org/book/appendix-07-nightly-rust.html">nightly channel</a>
+and requires the <code>-Z unstable-options</code> flag to enable.
+See <a href="https://github.com/rust-lang/cargo/issues/5579">https://github.com/rust-lang/cargo/issues/5579</a> for more information.</dd>
+
+
 </dl>
 
 

src/etc/man/cargo-add.1

@@ -140,6 +140,16 @@ crates, the features for a specific crate may be enabled with
 \fBpackage\-name/feature\-name\fR syntax. This flag may be specified multiple times,
 which enables all specified features.
 .RE
+.sp
+\fB\-\-ignore\-rust\-version\fR
+.RS 4
+Ignore \fBrust\-version\fR specification in packages.
+.sp
+This option is unstable and available only on the
+\fInightly channel\fR <https://doc.rust\-lang.org/book/appendix\-07\-nightly\-rust.html>
+and requires the \fB\-Z unstable\-options\fR flag to enable.
+See <https://github.com/rust\-lang/cargo/issues/5579> for more information.
+.RE
 .SS "Display Options"
 .sp
 \fB\-v\fR, 

tests/testsuite/cargo_add/mod.rs

@@ -102,6 +102,10 @@ mod quiet;
 mod registry;
 mod rename;
 mod require_weak;
+mod rust_version_ignore;
+mod rust_version_incompatible;
+mod rust_version_latest;
+mod rust_version_older;
 mod sorted_table_with_dotted_item;
 mod target;
 mod target_cfg;

tests/testsuite/cargo_add/rust_version_ignore/in/Cargo.toml

@@ -0,0 +1,6 @@
+[workspace]
+
+[package]
+name = "cargo-list-test-fixture"
+version = "0.0.0"
+rust-version = "1.68"

tests/testsuite/cargo_add/rust_version_ignore/mod.rs

@@ -0,0 +1,36 @@
+use cargo_test_support::compare::assert_ui;
+use cargo_test_support::prelude::*;
+use cargo_test_support::Project;
+
+use crate::cargo_add::init_registry;
+use cargo_test_support::curr_dir;
+
+#[cargo_test]
+fn case() {
+ init_registry();
+
+ cargo_test_support::registry::Package::new("rust-version-user", "0.1.0")
+ .rust_version("1.66")
+ .publish();
+ cargo_test_support::registry::Package::new("rust-version-user", "0.2.1")
+ .rust_version("1.72")
+ .publish();
+
+ let project = Project::from_template(curr_dir!().join("in"));
+ let project_root = project.root();
+ let cwd = &project_root;
+
+ snapbox::cmd::Command::cargo_ui()
+ .arg("-Zmsrv-policy")
+ .arg("add")
+ .arg("--ignore-rust-version")
+ .arg_line("rust-version-user")
+ .current_dir(cwd)
+ .masquerade_as_nightly_cargo(&["msrv-policy"])
+ .assert()
+ .success()
+ .stdout_matches_path(curr_dir!().join("stdout.log"))
+ .stderr_matches_path(curr_dir!().join("stderr.log"));
+
+ assert_ui().subset_matches(curr_dir!().join("out"), &project_root);
+}

tests/testsuite/cargo_add/rust_version_ignore/out/Cargo.toml

@@ -0,0 +1,9 @@
+[workspace]
+
+[package]
+name = "cargo-list-test-fixture"
+version = "0.0.0"
+rust-version = "1.68"
+
+[dependencies]
+rust-version-user = "0.2.1"

tests/testsuite/cargo_add/rust_version_ignore/stderr.log

@@ -0,0 +1,2 @@
+ Updating `dummy-registry` index
+ Adding rust-version-user v0.2.1 to dependencies.

tests/testsuite/cargo_add/rust_version_incompatible/in/Cargo.toml

@@ -0,0 +1,6 @@
+[workspace]
+
+[package]
+name = "cargo-list-test-fixture"
+version = "0.0.0"
+rust-version = "1.56"