rustc: Introduce Strict Version Hashes #12533
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
|
|
||
| let hash = hash::sip::hash(krate); | ||
| Svh { | ||
| hash: str::from_utf8_owned(~[ |
There was a problem hiding this comment.
std::iter::range_step(0, 64, 4).map(|i| hex(hash >> i) as char).collect()
|
Related #10207 |
|
We ended up having some non-determinism in our AST through two sources I found which made the stage1-generated and stage2-generated libsyntax libraries have different hashes. If these two libraries are different, it means all of the syntax extension tests start failing. This is obviously a hazard, but it wasn't too bad to fix.
After implementing these two fixes, I'm seeing stable version hashes between stage1/stage2. This is obviously still quite brittle, I believe, because things like the For now though, the tests seem to be passing. At least it helped uncover one real bug! |
The previous code passed around a {name,version} pair everywhere, but this is
better expressed as a CrateId. This patch changes these paths to store and pass
around crate ids instead of these pairs of name/version. This also prepares the
code to change the type of hash that is stored in crates.
This new SVH is used to uniquely identify all crates as a snapshot in time of their ABI/API/publicly reachable state. This current calculation is just a hash of the entire crate's AST. This is obviously incorrect, but it is currently the reality for today. This change threads through the new Svh structure which originates from crate dependencies. The concept of crate id hash is preserved to provide efficient matching on filenames for crate loading. The inspected hash once crate metadata is opened has been changed to use the new Svh. The goal of this hash is to identify when upstream crates have changed but downstream crates have not been recompiled. This will prevent the def-id drift problem where upstream crates were recompiled, thereby changing their metadata, but downstream crates were not recompiled. In the future this hash can be expanded to exclude contents of the AST like doc comments, but limitations in the compiler prevent this change from being made at this time. Closes rust-lang#10207
Previously, format!("{a}{b}", a=foo(), b=bar()) has foo() and bar() run in a
nondeterminisc order. This is clearly a non-desirable property, so this commit
uses iteration over a list instead of iteration over a hash map to provide
deterministic code generation of these format arguments.
bors
added a commit
that referenced
this pull request
Feb 28, 2014
These hashes are used to detect changes to upstream crates and generate errors which mention that crates possibly need recompilation. More details can be found in the respective commit messages below. This change is also accompanied with a much needed refactoring of some of the crate loading code to focus more on crate ids instead of name/version pairs. Closes #12601
flip1995
pushed a commit
to flip1995/rust
that referenced
this pull request
Apr 4, 2024
Remove unused dep `tester` changelog: none
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
These hashes are used to detect changes to upstream crates and generate errors which mention that crates possibly need recompilation.
More details can be found in the respective commit messages below. This change is also accompanied with a much needed refactoring of some of the crate loading code to focus more on crate ids instead of name/version pairs.
Closes #12601