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Auto merge of #14302 - weihanglo:check-cfg, r=epage
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fix: remove rustc probe for `--check-cfg` support

### What does this PR try to resolve?

This is a follow-up to #13571 as now everything for `-Z check-cfg` is stabilized.

### How should we test and review this PR?

Existing test suite passes.

### Additional information
  • Loading branch information
@bors
bors committed Jul 25, 2024
2 parents 0d0bab6 + acf64f7 commit 4f19191
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Showing 4 changed files with 64 additions and 107 deletions.
13 changes: 0 additions & 13 deletions src/cargo/core/compiler/build_context/target_info.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -54,11 +54,6 @@ pub struct TargetInfo {
pub rustflags: Rc<[String]>,
/// Extra flags to pass to `rustdoc`, see [`extra_args`].
pub rustdocflags: Rc<[String]>,
/// Whether or not rustc (stably) supports the `--check-cfg` flag.
///
/// Can be removed once the minimum supported rustc version of Cargo is
/// at minimum 1.80.0.
pub support_check_cfg: bool,
}

/// Kind of each file generated by a Unit, part of `FileType`.
Expand Down Expand Up @@ -204,13 +199,6 @@ impl TargetInfo {
process.arg("--crate-type").arg(crate_type.as_str());
}

let support_check_cfg = rustc
.cached_output(
process.clone().arg("--check-cfg").arg("cfg()"),
extra_fingerprint,
)
.is_ok();

process.arg("--print=sysroot");
process.arg("--print=split-debuginfo");
process.arg("--print=crate-name"); // `___` as a delimiter.
Expand Down Expand Up @@ -323,7 +311,6 @@ impl TargetInfo {
.into(),
cfg,
support_split_debuginfo,
support_check_cfg,
});
}
}
Expand Down
2 changes: 1 addition & 1 deletion src/cargo/core/compiler/build_runner/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -246,7 +246,7 @@ impl<'a, 'gctx> BuildRunner<'a, 'gctx> {
let mut args = compiler::extern_args(&self, unit, &mut unstable_opts)?;
args.extend(compiler::lto_args(&self, unit));
args.extend(compiler::features_args(unit));
args.extend(compiler::check_cfg_args(&self, unit)?);
args.extend(compiler::check_cfg_args(unit)?);

let script_meta = self.find_build_script_metadata(unit);
if let Some(meta) = script_meta {
Expand Down
25 changes: 1 addition & 24 deletions src/cargo/core/compiler/custom_build.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -405,11 +405,6 @@ fn build_work(build_runner: &mut BuildRunner<'_, '_>, unit: &Unit) -> CargoResul
paths::create_dir_all(&script_out_dir)?;

let nightly_features_allowed = build_runner.bcx.gctx.nightly_features_allowed;
let extra_check_cfg = build_runner
.bcx
.target_data
.info(unit.kind)
.support_check_cfg;
let targets: Vec<Target> = unit.pkg.targets().to_vec();
let msrv = unit.pkg.rust_version().cloned();
// Need a separate copy for the fresh closure.
Expand Down Expand Up @@ -557,7 +552,6 @@ fn build_work(build_runner: &mut BuildRunner<'_, '_>, unit: &Unit) -> CargoResul
&pkg_descr,
&script_out_dir,
&script_out_dir,
extra_check_cfg,
nightly_features_allowed,
&targets,
&msrv,
Expand Down Expand Up @@ -586,7 +580,6 @@ fn build_work(build_runner: &mut BuildRunner<'_, '_>, unit: &Unit) -> CargoResul
&pkg_descr,
&prev_script_out_dir,
&script_out_dir,
extra_check_cfg,
nightly_features_allowed,
&targets_fresh,
&msrv_fresh,
Expand Down Expand Up @@ -643,7 +636,6 @@ impl BuildOutput {
pkg_descr: &str,
script_out_dir_when_generated: &Path,
script_out_dir: &Path,
extra_check_cfg: bool,
nightly_features_allowed: bool,
targets: &[Target],
msrv: &Option<RustVersion>,
Expand All @@ -655,7 +647,6 @@ impl BuildOutput {
pkg_descr,
script_out_dir_when_generated,
script_out_dir,
extra_check_cfg,
nightly_features_allowed,
targets,
msrv,
Expand All @@ -666,15 +657,13 @@ impl BuildOutput {
///
/// * `pkg_descr` --- for error messages
/// * `library_name` --- for determining if `RUSTC_BOOTSTRAP` should be allowed
/// * `extra_check_cfg` --- for `--check-cfg` (if supported)
pub fn parse(
input: &[u8],
// Takes String instead of InternedString so passing `unit.pkg.name()` will give a compile error.
library_name: Option<String>,
pkg_descr: &str,
script_out_dir_when_generated: &Path,
script_out_dir: &Path,
extra_check_cfg: bool,
nightly_features_allowed: bool,
targets: &[Target],
msrv: &Option<RustVersion>,
Expand Down Expand Up @@ -921,14 +910,7 @@ impl BuildOutput {
linker_args.push((LinkArgTarget::All, value));
}
"rustc-cfg" => cfgs.push(value.to_string()),
"rustc-check-cfg" => {
if extra_check_cfg {
check_cfgs.push(value.to_string());
} else {
// silently ignoring the instruction because the rustc version
// we are using does not support --check-cfg stably
}
}
"rustc-check-cfg" => check_cfgs.push(value.to_string()),
"rustc-env" => {
let (key, val) = BuildOutput::parse_rustc_env(&value, &whence)?;
// Build scripts aren't allowed to set RUSTC_BOOTSTRAP.
Expand Down Expand Up @@ -1265,11 +1247,6 @@ fn prev_build_output(
&unit.pkg.to_string(),
&prev_script_out_dir,
&script_out_dir,
build_runner
.bcx
.target_data
.info(unit.kind)
.support_check_cfg,
build_runner.bcx.gctx.nightly_features_allowed,
unit.pkg.targets(),
&unit.pkg.rust_version().cloned(),
Expand Down
131 changes: 62 additions & 69 deletions src/cargo/core/compiler/mod.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -732,7 +732,7 @@ fn prepare_rustdoc(build_runner: &BuildRunner<'_, '_>, unit: &Unit) -> CargoResu
let doc_dir = build_runner.files().out_dir(unit);
rustdoc.arg("-o").arg(&doc_dir);
rustdoc.args(&features_args(unit));
rustdoc.args(&check_cfg_args(build_runner, unit)?);
rustdoc.args(&check_cfg_args(unit)?);

add_error_format_and_color(build_runner, &mut rustdoc);
add_allow_features(build_runner, &mut rustdoc);
Expand Down Expand Up @@ -1125,7 +1125,7 @@ fn build_base_args(
}

cmd.args(&features_args(unit));
cmd.args(&check_cfg_args(build_runner, unit)?);
cmd.args(&check_cfg_args(unit)?);

let meta = build_runner.files().metadata(unit);
cmd.arg("-C").arg(&format!("metadata={}", meta));
Expand Down Expand Up @@ -1310,83 +1310,76 @@ fn trim_paths_args(
}

/// Generates the `--check-cfg` arguments for the `unit`.
fn check_cfg_args(build_runner: &BuildRunner<'_, '_>, unit: &Unit) -> CargoResult<Vec<OsString>> {
if build_runner
.bcx
.target_data
.info(unit.kind)
.support_check_cfg
{
// The routine below generates the --check-cfg arguments. Our goals here are to
// enable the checking of conditionals and pass the list of declared features.
//
// In the simplified case, it would resemble something like this:
//
// --check-cfg=cfg() --check-cfg=cfg(feature, values(...))
//
// but having `cfg()` is redundant with the second argument (as well-known names
// and values are implicitly enabled when one or more `--check-cfg` argument is
// passed) so we don't emit it and just pass:
//
// --check-cfg=cfg(feature, values(...))
//
// This way, even if there are no declared features, the config `feature` will
// still be expected, meaning users would get "unexpected value" instead of name.
// This wasn't always the case, see rust-lang#119930 for some details.
fn check_cfg_args(unit: &Unit) -> CargoResult<Vec<OsString>> {
// The routine below generates the --check-cfg arguments. Our goals here are to
// enable the checking of conditionals and pass the list of declared features.
//
// In the simplified case, it would resemble something like this:
//
// --check-cfg=cfg() --check-cfg=cfg(feature, values(...))
//
// but having `cfg()` is redundant with the second argument (as well-known names
// and values are implicitly enabled when one or more `--check-cfg` argument is
// passed) so we don't emit it and just pass:
//
// --check-cfg=cfg(feature, values(...))
//
// This way, even if there are no declared features, the config `feature` will
// still be expected, meaning users would get "unexpected value" instead of name.
// This wasn't always the case, see rust-lang#119930 for some details.

let gross_cap_estimation = unit.pkg.summary().features().len() * 7 + 25;
let mut arg_feature = OsString::with_capacity(gross_cap_estimation);
let gross_cap_estimation = unit.pkg.summary().features().len() * 7 + 25;
let mut arg_feature = OsString::with_capacity(gross_cap_estimation);

arg_feature.push("cfg(feature, values(");
for (i, feature) in unit.pkg.summary().features().keys().enumerate() {
if i != 0 {
arg_feature.push(", ");
}
arg_feature.push("\"");
arg_feature.push(feature);
arg_feature.push("\"");
arg_feature.push("cfg(feature, values(");
for (i, feature) in unit.pkg.summary().features().keys().enumerate() {
if i != 0 {
arg_feature.push(", ");
}
arg_feature.push("))");

// We also include the `docsrs` cfg from the docs.rs service. We include it here
// (in Cargo) instead of rustc, since there is a much closer relationship between
// Cargo and docs.rs than rustc and docs.rs. In particular, all users of docs.rs use
// Cargo, but not all users of rustc (like Rust-for-Linux) use docs.rs.

let mut args = vec![
OsString::from("--check-cfg"),
OsString::from("cfg(docsrs)"),
OsString::from("--check-cfg"),
arg_feature,
];

// Also include the custom arguments specified in `[lints.rust.unexpected_cfgs.check_cfg]`
if let Ok(Some(lints)) = unit.pkg.manifest().resolved_toml().resolved_lints() {
if let Some(rust_lints) = lints.get("rust") {
if let Some(unexpected_cfgs) = rust_lints.get("unexpected_cfgs") {
if let Some(config) = unexpected_cfgs.config() {
if let Some(check_cfg) = config.get("check-cfg") {
if let Ok(check_cfgs) =
toml::Value::try_into::<Vec<String>>(check_cfg.clone())
{
for check_cfg in check_cfgs {
args.push(OsString::from("--check-cfg"));
args.push(OsString::from(check_cfg));
}
// error about `check-cfg` not being a list-of-string
} else {
bail!("`lints.rust.unexpected_cfgs.check-cfg` must be a list of string");
arg_feature.push("\"");
arg_feature.push(feature);
arg_feature.push("\"");
}
arg_feature.push("))");

// We also include the `docsrs` cfg from the docs.rs service. We include it here
// (in Cargo) instead of rustc, since there is a much closer relationship between
// Cargo and docs.rs than rustc and docs.rs. In particular, all users of docs.rs use
// Cargo, but not all users of rustc (like Rust-for-Linux) use docs.rs.

let mut args = vec![
OsString::from("--check-cfg"),
OsString::from("cfg(docsrs)"),
OsString::from("--check-cfg"),
arg_feature,
];

// Also include the custom arguments specified in `[lints.rust.unexpected_cfgs.check_cfg]`
if let Ok(Some(lints)) = unit.pkg.manifest().resolved_toml().resolved_lints() {
if let Some(rust_lints) = lints.get("rust") {
if let Some(unexpected_cfgs) = rust_lints.get("unexpected_cfgs") {
if let Some(config) = unexpected_cfgs.config() {
if let Some(check_cfg) = config.get("check-cfg") {
if let Ok(check_cfgs) =
toml::Value::try_into::<Vec<String>>(check_cfg.clone())
{
for check_cfg in check_cfgs {
args.push(OsString::from("--check-cfg"));
args.push(OsString::from(check_cfg));
}
// error about `check-cfg` not being a list-of-string
} else {
bail!(
"`lints.rust.unexpected_cfgs.check-cfg` must be a list of string"
);
}
}
}
}
}

Ok(args)
} else {
Ok(Vec::new())
}

Ok(args)
}

/// Adds LTO related codegen flags.
Expand Down

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