Add panic=immediate-abort support to Cargo (#16041)

I recently turned `-Zbuild-std-features=panic_immediate_abort` into
`-Cpanic=immediate-abort` in
rust-lang/rust#146317. There was some discussion
of the feature on Zulip here: [#t-compiler/major changes > Unstably add
-Cpanic=immediate-abort
compiler-team#909](https://rust-lang.zulipchat.com/#narrow/channel/233931-t-compiler.2Fmajor-changes/topic/Unstably.20add.20-Cpanic.3Dimmediate-abort.20compiler-team.23909/with/542845480)

One of the outcomes of this shipping in nightly is that a few use
patterns were broken, see
rust-lang/rust#146974 and
rust-lang/rust#146317 for examples. I think most
of the users commenting on these issues are having trouble with how
`RUSTFLAGS` is propagated through Cargo, and most likely they would have
just gotten what they wanted if they could have set a profile option
instead. So I'm trying to implement that.

Author: weihanglo

src/cargo/core/compiler/mod.rs

@@ -1234,6 +1234,9 @@ fn build_base_args(
     if *panic != PanicStrategy::Unwind {
         cmd.arg("-C").arg(format!("panic={}", panic));
     }
+    if *panic == PanicStrategy::ImmediateAbort {
+        cmd.arg("-Z").arg("unstable-options");
+    }
 
     cmd.args(&lto_args(build_runner, unit));
 
@@ -1305,7 +1308,7 @@ fn build_base_args(
         // flag to pass to rustc, so register that here. Eventually this flag
         // will simply not be needed when the behavior is stabilized in the Rust
         // compiler itself.
-        if *panic == PanicStrategy::Abort {
+        if *panic == PanicStrategy::Abort || *panic == PanicStrategy::ImmediateAbort {
             cmd.arg("-Z").arg("panic-abort-tests");
         }
     } else if test {

src/cargo/core/features.rs

@@ -579,6 +579,9 @@ features! {
 
     /// Allows use of multiple build scripts.
     (unstable, multiple_build_scripts, "", "reference/unstable.html#multiple-build-scripts"),
+
+    /// Allows use of panic="immediate-abort".
+    (unstable, panic_immediate_abort, "", "reference/unstable.html#panic-immediate-abort"),
 }
 
 /// Status and metadata for a single unstable feature.
@@ -872,6 +875,7 @@ unstable_cli_options!(
     no_embed_metadata: bool = ("Avoid embedding metadata in library artifacts"),
     no_index_update: bool = ("Do not update the registry index even if the cache is outdated"),
     panic_abort_tests: bool = ("Enable support to run tests with -Cpanic=abort"),
+    panic_immediate_abort: bool = ("Enable setting `panic = \"immediate-abort\"` in profiles"),
     profile_hint_mostly_unused: bool = ("Enable the `hint-mostly-unused` setting in profiles to mark a crate as mostly unused."),
     profile_rustflags: bool = ("Enable the `rustflags` option in profiles in .cargo/config.toml file"),
     public_dependency: bool = ("Respect a dependency's `public` field in Cargo.toml to control public/private dependencies"),
@@ -1417,6 +1421,7 @@ impl CliUnstable {
             "skip-rustdoc-fingerprint" => self.skip_rustdoc_fingerprint = parse_empty(k, v)?,
             "script" => self.script = parse_empty(k, v)?,
             "target-applies-to-host" => self.target_applies_to_host = parse_empty(k, v)?,
+            "panic-immediate-abort" => self.panic_immediate_abort = parse_empty(k, v)?,
             "unstable-options" => self.unstable_options = parse_empty(k, v)?,
             "warnings" => self.warnings = parse_empty(k, v)?,
             _ => bail!(

src/cargo/core/profiles.rs

@@ -561,6 +561,7 @@ fn merge_profile(profile: &mut Profile, toml: &TomlProfile) {
         profile.panic = match panic.as_str() {
             "unwind" => PanicStrategy::Unwind,
             "abort" => PanicStrategy::Abort,
+            "immediate-abort" => PanicStrategy::ImmediateAbort,
             // This should be validated in TomlProfile::validate
             _ => panic!("Unexpected panic setting `{}`", panic),
         };
@@ -872,17 +873,19 @@ impl serde::ser::Serialize for Lto {
 
 /// The `panic` setting.
 #[derive(Clone, Copy, PartialEq, Eq, Debug, Hash, PartialOrd, Ord, serde::Serialize)]
-#[serde(rename_all = "lowercase")]
+#[serde(rename_all = "kebab-case")]
 pub enum PanicStrategy {
     Unwind,
     Abort,
+    ImmediateAbort,
 }
 
 impl fmt::Display for PanicStrategy {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
             PanicStrategy::Unwind => "unwind",
             PanicStrategy::Abort => "abort",
+            PanicStrategy::ImmediateAbort => "immediate-abort",
         }
         .fmt(f)
     }

src/cargo/util/toml/mod.rs

@@ -2570,10 +2570,10 @@ pub fn validate_profile(
     }
 
     if let Some(panic) = &root.panic {
-        if panic != "unwind" && panic != "abort" {
+        if panic != "unwind" && panic != "abort" && panic != "immediate-abort" {
             bail!(
                 "`panic` setting of `{}` is not a valid setting, \
-                     must be `unwind` or `abort`",
+                     must be `unwind`, `abort`, or `immediate-abort`.",
                 panic
             );
         }
@@ -2627,6 +2627,15 @@ fn validate_profile_layer(
             _ => {}
         }
     }
+    if profile.panic.as_deref() == Some("immediate-abort") {
+        match (
+            features.require(Feature::panic_immediate_abort()),
+            cli_unstable.panic_immediate_abort,
+        ) {
+            (Err(e), false) => return Err(e),
+            _ => {}
+        }
+    }
     Ok(())
 }
 

src/doc/src/reference/unstable.md

@@ -95,6 +95,7 @@ Each new feature described below should explain how to use it.
     * [target-applies-to-host](#target-applies-to-host) --- Alters whether certain flags will be passed to host build targets.
     * [gc](#gc) --- Global cache garbage collection.
     * [open-namespaces](#open-namespaces) --- Allow multiple packages to participate in the same API namespace
+    * [panic-immediate-abort](#panic-immediate-abort) --- Passes `-Cpanic=immediate-abort` to the compiler.
 * rustdoc
     * [rustdoc-map](#rustdoc-map) --- Provides mappings for documentation to link to external sites like [docs.rs](https://docs.rs/).
     * [scrape-examples](#scrape-examples) --- Shows examples within documentation.
@@ -1674,6 +1675,24 @@ cargo-features = ["open-namespaces"]
 # ...
 ```
 
+## panic-immediate-abort
+
+* Tracking Issue: [#16042](https://github.com/rust-lang/cargo/issues/16042)
+* Upstream Tracking Issue: [rust-lang/rust#147286](https://github.com/rust-lang/rust/issues/147286)
+
+Allow use of [`-Cpanic=immediate-abort`](../../rustc/codegen-options/index.html#panic) through a Cargo profile
+
+This can be enabled like so:
+```toml
+cargo-features = ["immediate-abort"]
+
+[package]
+# ...
+
+[profile.release]
+panic = "immediate-abort"
+```
+
 ## `[lints.cargo]`
 
 * Tracking Issue: [#12235](https://github.com/rust-lang/cargo/issues/12235)

tests/testsuite/cargo/z_help/stdout.term.svg

@@ -150,6 +150,7 @@ mod proc_macro;
 mod profile_config;
 mod profile_custom;
 mod profile_overrides;
+mod profile_panic_immediate_abort;
 mod profile_targets;
 mod profile_trim_paths;
 mod profiles;

tests/testsuite/main.rs

@@ -0,0 +1,121 @@
+//! Tests for `panic = "immediate-abort"`.
+
+use crate::prelude::*;
+use cargo_test_support::project;
+use cargo_test_support::str;
+
+#[cargo_test]
+fn gated_manifest() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = "foo"
+                version = "0.0.1"
+                edition = "2015"
+
+                [profile.dev]
+                panic = "immediate-abort"
+           "#,
+        )
+        .file("src/lib.rs", "")
+        .build();
+
+    p.cargo("check")
+        .masquerade_as_nightly_cargo(&["panic-immediate-abort"])
+        .with_status(101)
+        .with_stderr_data(str![[r#"
+[ERROR] failed to parse manifest at `[ROOT]/foo/Cargo.toml`
+
+Caused by:
+  feature `panic-immediate-abort` is required
+...
+"#]])
+        .run();
+}
+
+#[cargo_test]
+fn gated_config_toml() {
+    let p = project()
+        .file(
+            ".cargo/config.toml",
+            r#"
+                [profile.dev]
+                panic = "immediate-abort"
+           "#,
+        )
+        .file("src/lib.rs", "")
+        .build();
+
+    p.cargo("check")
+        .masquerade_as_nightly_cargo(&["panic-immediate-abort"])
+        .with_status(101)
+        .with_stderr_data(str![[r#"
+[ERROR] config profile `dev` is not valid (defined in `[ROOT]/foo/.cargo/config.toml`)
+
+Caused by:
+  feature `panic-immediate-abort` is required
+...
+"#]])
+        .run();
+}
+
+#[cargo_test(nightly, reason = "-Cpanic=immediate-abort is unstable")]
+fn manifest_gate_works() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                cargo-features = ["panic-immediate-abort"]
+                [package]
+                name = "foo"
+                version = "0.0.1"
+                edition = "2015"
+
+                [profile.dev]
+                panic = "immediate-abort"
+           "#,
+        )
+        .file("src/lib.rs", "")
+        .build();
+
+    p.cargo("build --verbose")
+        .masquerade_as_nightly_cargo(&["panic-immediate-abort"])
+        .with_stderr_data(str![[r#"
+[COMPILING] foo v0.0.1 ([ROOT]/foo)
+[RUNNING] `rustc [..]-C panic=immediate-abort -Z unstable-options[..]`
+[FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
+
+"#]])
+        .run();
+}
+
+#[cargo_test(nightly, reason = "-Cpanic=immediate-abort is unstable")]
+fn cli_gate_works() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = "foo"
+                version = "0.0.1"
+                edition = "2015"
+
+                [profile.dev]
+                panic = "immediate-abort"
+           "#,
+        )
+        .file("src/lib.rs", "")
+        .build();
+
+    p.cargo("build --verbose -Z panic-immediate-abort")
+        .masquerade_as_nightly_cargo(&["panic-immediate-abort"])
+        .with_stderr_data(str![[r#"
+[COMPILING] foo v0.0.1 ([ROOT]/foo)
+[RUNNING] `rustc [..]-C panic=immediate-abort -Z unstable-options[..]`
+[FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
+
+"#]])
+        .run();
+}