Enable CARGO_CFG_DEBUG_ASSERTIONS in build scripts based on profile by moabo3li · Pull Request #16160 · rust-lang/cargo

moabo3li · 2025-10-27T07:28:17Z

Build scripts need to know whether debug assertions are enabled to properly configure dependencies with matching assertion behavior. Previously, CARGO_CFG_DEBUG_ASSERTIONS was filtered out because the cfg query to rustc doesn't include profile settings.

This PR manually sets CARGO_CFG_DEBUG_ASSERTIONS based on the profile's debug-assertions setting, allowing build scripts to configure dependencies appropriately.

FCP: #16160 (comment)

Closes #15760

rustbot · 2025-10-27T07:28:22Z

r? @ehuss

rustbot has assigned @ehuss.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

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crates/build-rs/src/input.rs

src/cargo/core/compiler/custom_build.rs

src/cargo/core/profiles.rs

src/cargo/core/compiler/custom_build.rs

tests/testsuite/build_script_env.rs

tests/testsuite/build.rs

rustbot · 2025-10-28T13:20:05Z

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

…ting fix(test): update test to reflect CARGO_CFG_DEBUG_ASSERTIONS is now passed to build scripts chore(deps): update build-rs to version 0.3.3 in Cargo.lock and Cargo.toml

…verride

…le override

…e for debug and release profiles

epage · 2025-10-28T18:50:42Z

tests/testsuite/build_script_env.rs

+#[cargo_test]
+fn build_script_debug_assertions_build_override() {
+    let build_rs = r#"
+        fn main() {
+            let profile = std::env::var("PROFILE").unwrap();
+            if profile == "debug" {
+                assert!(!cfg!(debug_assertions));
+            } else if profile == "release" {
+                assert!(cfg!(debug_assertions));
+            }
+        }
+    "#;
+
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = "foo"
+                version = "0.1.0"
+                edition = "2024"
+
+                [profile.dev.build-override]
+                debug-assertions = false
+
+                [profile.release.build-override]
+                debug-assertions = true
+            "#,
+        )
+        .file("src/lib.rs", r#""#)
+        .file("build.rs", build_rs)
+        .build();
+
+    p.cargo("check").run();
+    p.cargo("check --release").run();
+}


Why is this checking dev and release? The test is only relevant for the profile build-override is being used on

The test is checking both to verify that build-override correctly affects build script compilation in both profiles. It's showing the override works bidirectionally:
You can disable debug assertions for build scripts in dev (normally they're on)
You can enable debug assertions for build scripts in release (normally they're off)

Oh right, for some reason I had missed the use of build-override in both.

We don't really need tests for each of these two profiles. Once we test things in one profile, its sufficient for all.

…emove reference to debug_assertions

epage · 2025-10-28T20:07:13Z

tests/testsuite/build_script_env.rs

test(add): add test for CARGO_CFG_DEBUG_ASSERTIONS in dev profile

For future reference, in Conventional commits, add is the scope, or what this applies to. In this case you are sayign you are doing tests for cargo add.

epage

While some nits, this is good enough to go in. Thanks for your work on this!

View changes since this review

epage · 2025-10-28T20:09:18Z

@rfcbot fcp merge

Like with #14902, this adds an artificial CARGO_CFG to build scripts for --cfg debug_assertions. For more background, see #15760 (comment)

rust-rfcbot · 2025-10-28T20:09:20Z

Team member @epage has proposed to merge this. The next step is review by the rest of the tagged team members:

No concerns currently listed.

Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

See this document for info about what commands tagged team members can give me.

moabo3li · 2025-11-01T09:29:14Z

@rfcbot fcp merge

Like with #14902, this adds an artificial CARGO_CFG to build scripts for --cfg debug_assertions. For more background, see #15760 (comment)

Is there anything still needed to merge this?

weihanglo · 2025-11-01T12:03:53Z

As this is adding a user-facing change that we cannot revert after stabilization, we usually go through the FCP for this kind of one-way-door change. See #16160 (comment) for more about FCP process.

In the meanwhile you can address nits Ed had suggested, but in general nothing major is needed unless some concern is raised

rust-rfcbot · 2025-11-11T15:28:21Z

🔔 This is now entering its final comment period, as per the review above. 🔔

rust-rfcbot · 2025-11-21T15:28:52Z

The final comment period, with a disposition to merge, as per the review above, is now complete.

As the automated representative of the governance process, I would like to thank the author for their work and everyone else who contributed.

This will be merged soon.

epage · 2025-11-21T20:49:58Z

Thanks!

Update cargo submodule 7 commits in 5c0343317ce45d2ec17ecf41eaa473a02d73e29c..9fa462fe3a81e07e0bfdcc75c29d312c55113ebb 2025-11-18 19:05:44 +0000 to 2025-11-21 20:49:51 +0000 - Enable CARGO_CFG_DEBUG_ASSERTIONS in build scripts based on profile (rust-lang/cargo#16160) - fix(config-include): disallow glob and template syntax (rust-lang/cargo#16285) - test(config-include): include always relative to including config (rust-lang/cargo#16286) - docs(guide): When suggesting alt dev profile, link to related issue (rust-lang/cargo#16275) - refactor(timings): separate data collection and presentation (rust-lang/cargo#16282) - test(build-std): Add test for LTO (rust-lang/cargo#16277) - fix(bindeps): do not propagate artifact dependency to proc macro or build deps (rust-lang/cargo#15788) r? ghost

This MR contains the following updates: | Package | Update | Change | |---|---|---| | [rust](https://github.com/rust-lang/rust) | minor | `1.92.0` → `1.93.0` | MR created with the help of [el-capitano/tools/renovate-bot](https://gitlab.com/el-capitano/tools/renovate-bot). **Proposed changes to behavior should be submitted there as MRs.** --- ### Release Notes <details> <summary>rust-lang/rust (rust)</summary> ### [`v1.93.0`](https://github.com/rust-lang/rust/blob/HEAD/RELEASES.md#Version-1930-2026-01-22) [Compare Source](rust-lang/rust@1.92.0...1.93.0) \========================== <a id="1.93.0-Language"></a> ## Language - [Stabilize several s390x `vector`-related target features and the `is_s390x_feature_detected!` macro](rust-lang/rust#145656) - [Stabilize declaration of C-style variadic functions for the `system` ABI](rust-lang/rust#145954) - [Emit error when using some keyword as a `cfg` predicate](rust-lang/rust#146978) - [Stabilize `asm_cfg`](rust-lang/rust#147736) - [During const-evaluation, support copying pointers byte-by-byte](rust-lang/rust#148259) - [LUB coercions now correctly handle function item types, and functions with differing safeties](rust-lang/rust#148602) - [Allow `const` items that contain mutable references to `static` (which is *very* unsafe, but not *always* UB)](rust-lang/rust#148746) - [Add warn-by-default `const_item_interior_mutations` lint to warn against calls which mutate interior mutable `const` items](rust-lang/rust#148407) - [Add warn-by-default `function_casts_as_integer` lint](rust-lang/rust#141470) <a id="1.93.0-Compiler"></a> ## Compiler - [Stabilize `-Cjump-tables=bool`](rust-lang/rust#145974). The flag was previously called `-Zno-jump-tables`. <a id="1.93.0-Platform-Support"></a> ## Platform Support - [Promote `riscv64a23-unknown-linux-gnu` to Tier 2 (without host tools)](rust-lang/rust#148435) Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. [platform-support-doc]: https://doc.rust-lang.org/rustc/platform-support.html <a id="1.93.0-Libraries"></a> ## Libraries - [Stop internally using `specialization` on the `Copy` trait as it is unsound in the presence of lifetime dependent `Copy` implementations. This may result in some performance regressions as some standard library APIs may now call `Clone::clone` instead of performing bitwise copies](rust-lang/rust#135634) - [Allow the global allocator to use thread-local storage and `std::thread::current()`](rust-lang/rust#144465) - [Make `BTree::append` not update existing keys when appending an entry which already exists](rust-lang/rust#145628) - [Don't require `T: RefUnwindSafe` for `vec::IntoIter<T>: UnwindSafe`](rust-lang/rust#145665) <a id="1.93.0-Stabilized-APIs"></a> ## Stabilized APIs - [`<[MaybeUninit<T>]>::assume_init_drop`](https://doc.rust-lang.org/stable/core/primitive.slice.html#method.assume_init_drop) - [`<[MaybeUninit<T>]>::assume_init_ref`](https://doc.rust-lang.org/stable/core/primitive.slice.html#method.assume_init_ref) - [`<[MaybeUninit<T>]>::assume_init_mut`](https://doc.rust-lang.org/stable/core/primitive.slice.html#method.assume_init_mut) - [`<[MaybeUninit<T>]>::write_copy_of_slice`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.write_copy_of_slice) - [`<[MaybeUninit<T>]>::write_clone_of_slice`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.write_clone_of_slice) - [`String::into_raw_parts`](https://doc.rust-lang.org/stable/std/string/struct.String.html#method.into_raw_parts) - [`Vec::into_raw_parts`](https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.into_raw_parts) - [`<iN>::unchecked_neg`](https://doc.rust-lang.org/stable/std/primitive.isize.html#method.unchecked_neg) - [`<iN>::unchecked_shl`](https://doc.rust-lang.org/stable/std/primitive.isize.html#method.unchecked_shl) - [`<iN>::unchecked_shr`](https://doc.rust-lang.org/stable/std/primitive.isize.html#method.unchecked_shr) - [`<uN>::unchecked_shl`](https://doc.rust-lang.org/stable/std/primitive.usize.html#method.unchecked_shl) - [`<uN>::unchecked_shr`](https://doc.rust-lang.org/stable/std/primitive.usize.html#method.unchecked_shr) - [`<[T]>::as_array`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_array) - [`<[T]>::as_array_mut`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_mut_array) - [`<*const [T]>::as_array`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.as_array) - [`<*mut [T]>::as_array_mut`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.as_mut_array) - [`VecDeque::pop_front_if`](https://doc.rust-lang.org/stable/std/collections/struct.VecDeque.html#method.pop_front_if) - [`VecDeque::pop_back_if`](https://doc.rust-lang.org/stable/std/collections/struct.VecDeque.html#method.pop_back_if) - [`Duration::from_nanos_u128`](https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.from_nanos_u128) - [`char::MAX_LEN_UTF8`](https://doc.rust-lang.org/stable/std/primitive.char.html#associatedconstant.MAX_LEN_UTF8) - [`char::MAX_LEN_UTF16`](https://doc.rust-lang.org/stable/std/primitive.char.html#associatedconstant.MAX_LEN_UTF16) - [`std::fmt::from_fn`](https://doc.rust-lang.org/stable/std/fmt/fn.from_fn.html) - [`std::fmt::FromFn`](https://doc.rust-lang.org/stable/std/fmt/struct.FromFn.html) <a id="1.93.0-Cargo"></a> ## Cargo - [Enable CARGO\_CFG\_DEBUG\_ASSERTIONS in build scripts based on profile](rust-lang/cargo#16160) - [In `cargo tree`, support long forms for `--format` variables](rust-lang/cargo#16204) - [Add `--workspace` to `cargo clean`](rust-lang/cargo#16263) <a id="1.93.0-Rustdoc"></a> ## Rustdoc - [Remove `#![doc(document_private_items)]`](rust-lang/rust#146495) - [Include attribute and derive macros in search filters for "macros"](rust-lang/rust#148176) - [Include extern crates in search filters for `import`](rust-lang/rust#148301) - [Validate usage of crate-level doc attributes](rust-lang/rust#149197). This means if any of `html_favicon_url`, `html_logo_url`, `html_playground_url`, `issue_tracker_base_url`, or `html_no_source` either has a missing value, an unexpected value, or a value of the wrong type, rustdoc will emit the deny-by-default lint `rustdoc::invalid_doc_attributes`. <a id="1.93.0-Compatibility-Notes"></a> ## Compatibility Notes - [Introduce `pin_v2` into the builtin attributes namespace](rust-lang/rust#139751) - [Update bundled musl to 1.2.5](rust-lang/rust#142682) - [On Emscripten, the unwinding ABI used when compiling with `panic=unwind` was changed from the JS exception handling ABI to the wasm exception handling ABI.](rust-lang/rust#147224) If linking C/C++ object files with Rust objects, `-fwasm-exceptions` must be passed to the linker now. On nightly Rust, it is possible to get the old behavior with `-Zwasm-emscripten-eh=false -Zbuild-std`, but it will be removed in a future release. - The `#[test]` attribute, used to define tests, was previously ignored in various places where it had no meaning (e.g on trait methods or types). Putting the `#[test]` attribute in these places is no longer ignored, and will now result in an error; this may also result in errors when generating rustdoc. [Error when `test` attribute is applied to structs](rust-lang/rust#147841) - Cargo now sets the `CARGO_CFG_DEBUG_ASSERTIONS` environment variable in more situations. This will cause crates depending on `static-init` versions 1.0.1 to 1.0.3 to fail compilation with "failed to resolve: use of unresolved module or unlinked crate `parking_lot`". See [the linked issue](rust-lang/rust#150646 (comment)) for details. - [User written types in the `offset_of!` macro are now checked to be well formed.](rust-lang/rust#150465) - `cargo publish` no longer emits `.crate` files as a final artifact for user access when the `build.build-dir` config is unset - [Upgrade the `deref_nullptr` lint from warn-by-default to deny-by-default](rust-lang/rust#148122) - [Add future-incompatibility warning for `...` function parameters without a pattern outside of `extern` blocks](rust-lang/rust#143619) - [Introduce future-compatibility warning for `repr(C)` enums whose discriminant values do not fit into a `c_int` or `c_uint`](rust-lang/rust#147017) - [Introduce future-compatibility warning against ignoring `repr(C)` types as part of `repr(transparent)`](rust-lang/rust#147185) </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever MR becomes conflicted, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this MR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this MR, check this box --- This MR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).

Pkgsrc changes: * Update version & checksums. * Adapt openssl-src patches to minor version update. Noteable failures at the time of commit: * The cross-build for sparc64 fails, not yet reported. Upstream changes relative to 1.92.0: Version 1.93 (2026-01-22) ========================== Language -------- - [Add warn-by-default `function_casts_as_integer` lint] (rust-lang/rust#141470) - [Add future-incompatibility warning for `...` function parameters without a pattern outside of `extern` blocks] (rust-lang/rust#143619) - [Stabilize several s390x `vector`-related target features and the `is_s390x_feature_detected!` macro] (rust-lang/rust#145656) - [Stabilize declaration of C-style variadic functions for the `system` ABI] (rust-lang/rust#145954) - [Emit error when using some keyword as a `cfg` predicate] (rust-lang/rust#146978) - [Introduce future-compatibility warning for `repr(C)` enums whose discriminant values do not fit into a `c_int` or `c_uint`] (rust-lang/rust#147017) - [Introduce future-compatibility warning against ignoring `repr(C)` types as part of `repr(transparent)`] (rust-lang/rust#147185) - [Stabilize `asm_cfg`] (rust-lang/rust#147736) - [Upgrade the `deref_nullptr` lint from warn-by-default to deny-by-default] (rust-lang/rust#148122) - [During const-evaluation, support copying pointers byte-by-byte] (rust-lang/rust#148259) - [Add warn-by-default `const_item_interior_mutations` lint to warn against calls which mutate interior mutable `const` items] (rust-lang/rust#148407) - [LUB coercions now correctly handle function item types, and functions with differing safeties] (rust-lang/rust#148602) - [Allow `const` items that contain mutable references to `static` (which is *very* unsafe, but not *always* UB)] (rust-lang/rust#148746) Compiler -------- - [Stabilize `-Cjump-tables=bool`] (rust-lang/rust#145974). The flag was previously called `-Zno-jump-tables`. - [Promote `riscv64a23-unknown-linux-gnu` to Tier 2 (without host tools)] (rust-lang/rust#148435) Platform Support ---------------- Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. [platform-support-doc]: https://doc.rust-lang.org/rustc/platform-support.html Libraries --------- - [Stop internally using `specialization` on the `Copy` trait as it is unsound in the presence of lifetime dependent `Copy` implementations. This may result in some performance regressions as some standard library APIs may now call `Clone::clone` instead of performing bitwise copies] (rust-lang/rust#135634) - [Allow the global allocator to use thread-local storage and `std::thread::current()`] (rust-lang/rust#144465) - [Make `BTree::append` not update existing keys when appending an entry which already exists] (rust-lang/rust#145628) - [Don't require `T: RefUnwindSafe` for `vec::IntoIter<T>: UnwindSafe`] (rust-lang/rust#145665) Stabilized APIs --------------- - [`<MaybeUninit<T>>::assume_init_drop`] (https://doc.rust-lang.org/stable/core/mem/union.MaybeUninit.html#method.assume_init_drop) - [`<MaybeUninit<T>>::assume_init_ref`] (https://doc.rust-lang.org/stable/core/mem/union.MaybeUninit.html#method.assume_init_ref) - [`<MaybeUninit<T>>::assume_init_mut`] (https://doc.rust-lang.org/stable/core/mem/union.MaybeUninit.html#method.assume_init_mut) - [`<[MaybeUninit<T>]>::write_copy_of_slice`] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.write_copy_of_slice) - [`<[MaybeUninit<T>]>::write_clone_of_slice`] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.write_clone_of_slice) - [`String::into_raw_parts`] (https://doc.rust-lang.org/stable/std/string/struct.String.html#method.into_raw_parts) - [`Vec::into_raw_parts`] (https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.into_raw_parts) - [`<iN>::unchecked_neg`] (https://doc.rust-lang.org/stable/std/primitive.isize.html#method.unchecked_neg) - [`<iN>::unchecked_shl`] (https://doc.rust-lang.org/stable/std/primitive.isize.html#method.unchecked_shl) - [`<iN>::unchecked_shr`] (https://doc.rust-lang.org/stable/std/primitive.isize.html#method.unchecked_shr) - [`<uN>::unchecked_shl`] (https://doc.rust-lang.org/stable/std/primitive.usize.html#method.unchecked_shl) - [`<uN>::unchecked_shr`] (https://doc.rust-lang.org/stable/std/primitive.usize.html#method.unchecked_shr) - [`<[T]>::as_array`] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_array) - [`<[T]>::as_array_mut`] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_mut_array) - [`<*const [T]>::as_array`] (https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.as_array) - [`<*mut [T]>::as_array_mut`] (https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.as_mut_array) - [`VecDeque::pop_front_if`] (https://doc.rust-lang.org/stable/std/collections/struct.VecDeque.html#method.pop_front_if) - [`VecDeque::pop_back_if`] (https://doc.rust-lang.org/stable/std/collections/struct.VecDeque.html#method.pop_back_if) - [`Duration::from_nanos_u128`] (https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.from_nanos_u128) - [`char::MAX_LEN_UTF8`] (https://doc.rust-lang.org/stable/std/primitive.char.html#associatedconstant.MAX_LEN_UTF8) - [`char::MAX_LEN_UTF16`] (https://doc.rust-lang.org/stable/std/primitive.char.html#associatedconstant.MAX_LEN_UTF16) - [`std::fmt::from_fn`] (https://doc.rust-lang.org/stable/std/fmt/fn.from_fn.html) - [`std::fmt::FromFn`] (https://doc.rust-lang.org/stable/std/fmt/struct.FromFn.html) Cargo ----- - [Enable CARGO_CFG_DEBUG_ASSERTIONS in build scripts based on profile] (rust-lang/cargo#16160) - [In `cargo tree`, support long forms for `--format` variables] (rust-lang/cargo#16204) - [Add `--workspace` to `cargo clean`] (rust-lang/cargo#16263) Rustdoc ----- - [Remove `#![doc(document_private_items)]`](rust-lang/rust#146495) - [Include attribute and derive macros in search filters for "macros"](rust-lang/rust#148176) - [Include extern crates in search filters for `import`](rust-lang/rust#148301) - [Validate usage of crate-level doc attributes](rust-lang/rust#149197). This means if any of `html_favicon_url`, `html_logo_url`, `html_playground_url`, `issue_tracker_base_url`, or `html_no_source` either has a missing value, an unexpected value, or a value of the wrong type, rustdoc will emit the deny-by-default lint `rustdoc::invalid_doc_attributes`. Compatibility Notes ------------------- - [Introduce `pin_v2` into the builtin attributes namespace] (rust-lang/rust#139751) - [Update bundled musl to 1.2.5] (rust-lang/rust#142682) - [On Emscripten, the unwinding ABI used when compiling with `panic=unwind` was changed from the JS exception handling ABI to the wasm exception handling ABI.] (rust-lang/rust#147224) If linking C/C++ object files with Rust objects, `-fwasm-exceptions` must be passed to the linker now. On nightly Rust, it is possible to get the old behavior with `-Zwasm-emscripten-eh=false -Zbuild-std`, but it will be removed in a future release. - The `#[test]` attribute, used to define tests, was previously ignored in various places where it had no meaning (e.g on trait methods or types). Putting the `#[test]` attribute in these places is no longer ignored, and will now result in an error; this may also result in errors when generating rustdoc. [Error when `test` attribute is applied to structs] (rust-lang/rust#147841) - Cargo now sets the `CARGO_CFG_DEBUG_ASSERTIONS` environment variable in more situations. This will cause crates depending on `static-init` versions 1.0.1 to 1.0.3 to fail compilation with "failed to resolve: use of unresolved module or unlinked crate `parking_lot`". See [the linked issue] (rust-lang/rust#150646 (comment)) for details. - [User written types in the `offset_of!` macro are now checked to be well formed.] (rust-lang/rust#150465) - `cargo publish` no longer emits `.crate` files as a final artifact for user access when the `build.build-dir` config is unset

rustbot assigned ehuss Oct 27, 2025

rustbot added A-build-scripts Area: build.rs scripts A-profiles Area: profiles S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Oct 27, 2025

moabo3li force-pushed the debug_assertion_handling branch from 76b11fa to 72144ac Compare October 27, 2025 07:40