Auto merge of #11960 - ehuss:chdir-unstable, r=weihanglo

Change -C to be unstable

Due to #11957, we have decided to change `-C` to be unstable to give us some more time to decide on how it should behave.

Author: bors

CHANGELOG.md

@@ -67,8 +67,6 @@
 
 ### Added
 
-- Added `-C` flag for changing current dir before build starts.
-  [#10952](https://github.com/rust-lang/cargo/pull/10952)
 - Cargo now suggests `cargo fix` or `cargo clippy --fix`
   when compilation warnings are auto-fixable.
   [#11558](https://github.com/rust-lang/cargo/pull/11558)
@@ -130,6 +128,8 @@
 - Emit an error message for transitive artifact dependencies with targets the
   package doesn't directly interact with.
   [#11643](https://github.com/rust-lang/cargo/pull/11643)
+- Added `-C` flag for changing current dir before build starts.
+  [#10952](https://github.com/rust-lang/cargo/pull/10952)
 
 ### Documentation
 

src/bin/cargo/cli.rs

@@ -31,6 +31,23 @@ pub fn main(config: &mut LazyConfig) -> CliResult {
     // This must be completed before config is initialized
     assert_eq!(config.is_init(), false);
     if let Some(new_cwd) = args.get_one::<std::path::PathBuf>("directory") {
+        // This is a temporary hack. This cannot access `Config`, so this is a bit messy.
+        // This does not properly parse `-Z` flags that appear after the subcommand.
+        // The error message is not as helpful as the standard one.
+        let nightly_features_allowed = matches!(&*features::channel(), "nightly" | "dev");
+        if !nightly_features_allowed
+            || (nightly_features_allowed
+                && !args
+                    .get_many("unstable-features")
+                    .map(|mut z| z.any(|value: &String| value == "unstable-options"))
+                    .unwrap_or(false))
+        {
+            return Err(anyhow::format_err!(
+                "the `-C` flag is unstable, \
+                 pass `-Z unstable-options` on the nightly channel to enable it"
+            )
+            .into());
+        }
         std::env::set_current_dir(&new_cwd).context("could not change to requested directory")?;
     }
 
@@ -479,7 +496,7 @@ See 'cargo help <command>' for more information on a specific command.\n",
         )
         .arg(
             Arg::new("directory")
-                .help("Change to DIRECTORY before doing anything")
+                .help("Change to DIRECTORY before doing anything (nightly-only)")
                 .short('C')
                 .value_name("DIRECTORY")
                 .value_hint(clap::ValueHint::DirPath)

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

@@ -195,6 +195,11 @@ OPTIONS
            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.
 

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

@@ -380,6 +380,11 @@ OPTIONS
            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.
 

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

@@ -322,6 +322,11 @@ OPTIONS
            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.
 

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

@@ -307,6 +307,11 @@ OPTIONS
            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.
 

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

@@ -136,6 +136,11 @@ OPTIONS
            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.
 

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

@@ -278,6 +278,11 @@ OPTIONS
            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.
 

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

@@ -121,6 +121,11 @@ OPTIONS
            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.
 

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

@@ -380,6 +380,11 @@ OPTIONS
            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.