Works on debug build, but not on release build.

[OskarKarpinski]

I tried this code:

https://github.com/MedzikUser/rust-issue-101130

I expected it to work in the release build

Instead, this happened work only in debug build

About code:
This is a simple cryptography library which generates encryption key and encode text in build time.

For example, in the release build version if the key during the build is 7. Then during the runtime, key is for example, 39.

The same code on debug build always have the same key

Meta

rustc --version --verbose:

rustc 1.63.0 (4b91a6ea7 2022-08-08)
binary: rustc
commit-hash: 4b91a6ea7258a947e59c6522cd5898e7c0a6a88f
commit-date: 2022-08-08
host: x86_64-unknown-linux-gnu
release: 1.63.0
LLVM version: 14.0.5

(latest stable)

and

rustc 1.65.0-nightly (eaadb8947 2022-08-27)
binary: rustc
commit-hash: eaadb8947b850a025404082f6297766c4680a42a
commit-date: 2022-08-27
host: x86_64-unknown-linux-gnu
release: 1.65.0-nightly
LLVM version: 15.0.0

(latest nightly)

[zirconium-n]

Note: OP used a non-deterministic proc-macro to generate a const KEY at comptime, which is used by the main crate and another proc-macro macro (which is used by the main crate).

What's happening here is that, in release build, the KEY in macro is different from the KEY in main.

This can be reproduced with replacing OP's random proc-macro with const-random crate on crates.io.

[veber-alex]

All profiles, by default, do not optimize build dependencies (build scripts, proc macros, and their dependencies).

In dev profile the key crate is compiled without optimizations and both the binary and the proc macro use the same artifacts, which means KEY is the same.
In release profile the proc macro and the binary use different artifacts of the key crate which means different KEY.

Adding

[profile.release.build-override]
opt-level = 3

to the binary crate resolves the issue.

[OskarKarpinski]

Adding

[profile.release.build-override]
opt-level = 3

to the binary crate resolves the issue.

Using build.rs which generates and adds a key to env also solves this issue.

[Enselic]

Triage: Does not seem like a rustc bug. Closing.