This project reproduces a bug happening with cargo as of cargo 1.83.0 (5ffbef321 2024-10-29) (and earlier):

When running cargo doc incrementally, edits to files are not detected, ending up in a previous doc version.

Run cargo doc --open.

Output is:

 Documenting crate1 v0.1.0 (/path/to/here/crate1)
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.17s
     Opening /path/to/here/target/doc/crate1/index.html

Change some documentation in src/lib.rs (and save).

Run again cargo doc --open.

Output is:

    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.00s
     Opening /path/to/here/target/doc/crate1/index.html

But should be the same as before. Notice the opened documentation still shows the previous content.

Run cargo clean (with -p package in bigger projects to avoid too expensive recompilation).