rust/compiler/rustc_expand
bors 8188f6c808 Auto merge of #149709 - Urgau:overhaul-filenames, r=davidtwco
Overhaul filename handling for cross-compiler consistency

This PR overhauls the way we handle filenames in the compiler and `rmeta` in order to achieve achieve cross-compiler consistency (ie. having the same path no matter if the filename was created in the current compiler session or is coming from `rmeta`).

This is required as some parts of the compiler rely on consistent paths for the soundness of generated code (see rust-lang/rust#148328).

In order to achieved consistency multiple steps are being taken by this PR:
 - by making `RealFileName` immutable
 - by only having `SourceMap::to_real_filename` create `RealFileName`
   - currently `RealFileName` can be created from any `Path` and are remapped afterwards, which creates consistency issue
 - by also making `RealFileName` holds it's working directory, embeddable name and the remapped scopes
   - this removes the need for a `Session`, to know the current(!) scopes and cwd, which is invalid as they may not be equal to the scopes used when creating the filename

In order for `SourceMap::to_real_filename` to know which scopes to apply `FilePathMapping` now takes the current remapping scopes to apply, which makes `FileNameDisplayPreference` and company useless and are removed.

This PR is split-up in multiple commits (unfortunately not atomic), but should help review the changes.

Unblocks https://github.com/rust-lang/rust/pull/147611
Fixes https://github.com/rust-lang/rust/issues/148328
2025-12-13 14:32:09 +00:00
..
src Auto merge of #149709 - Urgau:overhaul-filenames, r=davidtwco 2025-12-13 14:32:09 +00:00
Cargo.toml Revert introduction of [workspace.dependencies]. 2025-09-02 19:12:54 +10:00
messages.ftl Rollup merge of #147438 - reddevilmidzy:rename-non-inline-module-in-msg, r=fee1-dead 2025-10-18 23:54:44 +02:00