##// END OF EJS Templates
rust: fix unsound `OwningDirstateMap`...
rust: fix unsound `OwningDirstateMap` As per the previous patch, `OwningDirstateMap` is unsound. Self-referential structs are difficult to implement correctly in Rust since the compiler is free to move structs around as much as it wants to. They are also very rarely needed in practice, so the state-of-the-art on how they should be done within the Rust rules is still a bit new. The crate `ouroboros` is an attempt at providing a safe way (in the Rust sense) of declaring self-referential structs. It is getting a lot attention and was improved very quickly when soundness issues were found in the past: rather than relying on our own (limited) review circle, we might as well use the de-facto common crate to fix this problem. This will give us a much better chance of finding issues should any new ones be discovered as well as the benefit of fewer `unsafe` APIs of our own. I was starting to think about how I would present a safe API to the old struct but soon realized that the callback-based approach was already done in `ouroboros`, along with a lot more care towards refusing incorrect structs. In short: we don't return a mutable reference to the `DirstateMap` anymore, we expect users of its API to pass a `FnOnce` that takes the map as an argument. This allows our `OwningDirstateMap` to control the input and output lifetimes of the code that modifies it to prevent such issues. Changing to `ouroboros` meant changing every API with it, but it is relatively low churn in the end. It correctly identified the example buggy modification of `copy_map_insert` outlined in the previous patch as violating the borrow rules. Differential Revision: https://phab.mercurial-scm.org/D12429

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r47474:97ac588b default
r49857:c9f44fc9 stable
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root.rs
28 lines | 889 B | application/rls-services+xml | RustLexer
Antoine Cezar
rhg: simplify `FindRootError` handling...
r45922 use crate::error::CommandError;
Raphaël Gomès
rhg: use `format_bytes!` for error messages...
r46598 use format_bytes::format_bytes;
Simon Sapin
rhg: Don’t make repository path absolute too early...
r47474 use hg::errors::{IoErrorContext, IoResultExt};
Antoine Cezar
rhg: add RootCommand using hg-core FindRoot operation to prepare `hg root`...
r45592 use hg::utils::files::get_bytes_from_path;
pub const HELP_TEXT: &str = "
Print the root directory of the current repository.
Returns 0 on success.
";
Simon Sapin
rhg: Move subcommand CLI arguments definitions to respective modules...
r47251 pub fn args() -> clap::App<'static, 'static> {
clap::SubCommand::with_name("root").about(HELP_TEXT)
}
Simon Sapin
rhg: Group values passed to every sub-command into a struct...
r47334 pub fn run(invocation: &crate::CliInvocation) -> Result<(), CommandError> {
Simon Sapin
rhg: Move `Repo` object creation into `main()`...
r47335 let repo = invocation.repo?;
Simon Sapin
rhg: Don’t make repository path absolute too early...
r47474 let working_directory = repo.working_directory_path();
let working_directory = std::fs::canonicalize(working_directory)
.with_context(|| {
IoErrorContext::CanonicalizingPath(working_directory.to_owned())
})?;
let bytes = get_bytes_from_path(&working_directory);
Simon Sapin
rhg: Group values passed to every sub-command into a struct...
r47334 invocation
.ui
.write_stdout(&format_bytes!(b"{}\n", bytes.as_slice()))?;
Simon Sapin
rhg: replace command structs with functions...
r47250 Ok(())
Antoine Cezar
rhg: add RootCommand using hg-core FindRoot operation to prepare `hg root`...
r45592 }