rust/tests/incremental/link_order/main.rs

// aux-build:my_lib.rs
// error-pattern: error: linking with
// revisions:cfail1 cfail2
// compile-flags:-Z query-dep-graph

// Tests that re-ordering the `-l` arguments used
// when compiling an external dependency does not lead to
// an 'unstable fingerprint' error.

extern crate my_lib;

fn main() {}
Don't sort a `Vec` before computing its `DepTrackingHash` Previously, we sorted the vec prior to hashing, making the hash independent of the original (command-line argument) order. However, the original vec was still always kept in the original order, so we were relying on the rest of the compiler always working with it in an 'order-independent' way. This assumption was not being upheld by the `native_libraries` query - the order of the entires in its result depends on the order of entries in `Options.libs`. This lead to an 'unstable fingerprint' ICE when the `-l` arguments were re-ordered. This PR removes the sorting logic entirely. Re-ordering command-line arguments (without adding/removing/changing any arguments) seems like a really niche use case, and correctly optimizing for it would require additional work. By always hashing arguments in their original order, we can entirely avoid a cause of 'unstable fingerprint' errors. 2021-05-25 19:43:02 -05:00			`// aux-build:my_lib.rs`
			`// error-pattern: error: linking with`
			`// revisions:cfail1 cfail2`
			`// compile-flags:-Z query-dep-graph`

			// Tests that re-ordering the `-l` arguments used
			`// when compiling an external dependency does not lead to`
			`// an 'unstable fingerprint' error.`

			`extern crate my_lib;`

			`fn main() {}`