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Stabilize String::leak #109814
Stabilize String::leak #109814
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r? @m-ou-se (rustbot has picked a reviewer for you, use r? to override) |
Hey! It looks like you've submitted a new PR for the library teams! If this PR contains changes to any Examples of
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Stabilization proposalI propose stabilizing the following API: impl String {
pub fn leak(self) -> &'static mut str;
} The ACP was in rust-lang/libs-team#109 . Implementation historyIt was implemented by #103280 . An earlier attempt was at #102941. Design considerationsThe added function is similar to already existing
Strings are always over bytes/chars so the first point isn't a concern for us, nor are allocators one because Strings don't implement custom allocators (yet). This explains the difference why we return a If/when we add an explicit allocator to cc @finnbear @dtolnay as you were involved in the original ACP. |
Does this API make them impossible in the future? I think it doesn't as going to a unbounded lifetime should be backwards compatible but it would be good to mention that here more explicitly. |
@Nilstrieb I hope not. I made my comment with the assumption there isn't. The ACP had a generic lifetime and the PR had a |
@rustbot label +T-libs-api -T-libs |
@Nilstrieb I've added a paragraph about the breakage concerns of explicit lifetime parameters. |
@m-ou-se friendly ping! It would be nice to have an FCP for stabilization. A stabilization proposal can be found above. |
r? libs-api |
@rust-lang/libs-api: Stabilization report: #109814 (comment) |
Team member @dtolnay has proposed to merge this. The next step is review by the rest of the tagged team members: Concerns:
Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up! See this document for info about what commands tagged team members can give me. |
Is it easy to just use an unbounded lifetime here and avoid the question of whether adding it later is a breaking change? |
Yes, this should return an unbounded lifetime instead of @rfcbot concern unbounded lifetime |
@BurntSushi @m-ou-se @joshtriplett could you maybe take a look at the FCP above? Also, it would be great for someone to review #111656, it should address @Amanieu and @BurntSushi 's concerns. I have asked for more docs in that PR but I can also just add them to this one once #111656 is merged. |
Consider the author of #111656 hasn't responded in over a week, I think it's fine to make the doc changes here. |
@rfcbot resolve unbounded lifetime |
Apologies for forgetting to respond. I think the wording "This is mainly useful for data that lives for the remainder of the program's life." and the |
…etime, r=Amanieu Use an unbounded lifetime in `String::leak`. Using `'a` instead of `'static` is predicted to make the process of making `String` generic over an allocator easier/less of a breaking change. See: - rust-lang#109814 (comment) - rust-lang#109814 (comment) ACP: rust-lang/libs-team#109
I'd just add something like this similar to what
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Re improving docs here vs in #111656, I guess given that I have a PR for String::leak open already (this one), it's easiest for me to just modify my PR, especially as it was me who brought up the concern. I have pushed a proposed wording:
The reason why I asked for docs is that when I looked up the docs for |
🔔 This is now entering its final comment period, as per the review above. 🔔 |
The final comment period, with a disposition to merge, as per the review above, is now complete. As the automated representative of the governance process, I would like to thank the author for their work and everyone else who contributed. This will be merged soon. |
@bors r+ rollup |
…iaskrgr Rollup of 6 pull requests Successful merges: - rust-lang#98202 (Implement `TryFrom<&OsStr>` for `&str`) - rust-lang#107619 (Specify behavior of HashSet::insert) - rust-lang#109814 (Stabilize String::leak) - rust-lang#111974 (Update runtime guarantee for `select_nth_unstable`) - rust-lang#112109 (Don't print unsupported split-debuginfo modes with `-Zunstable-options`) - rust-lang#112506 (Properly check associated consts for infer placeholders) r? `@ghost` `@rustbot` modify labels: rollup
…Amanieu Use an unbounded lifetime in `String::leak`. Using `'a` instead of `'static` is predicted to make the process of making `String` generic over an allocator easier/less of a breaking change. See: - rust-lang/rust#109814 (comment) - rust-lang/rust#109814 (comment) ACP: rust-lang/libs-team#109
- misc. updates. ---- # improve unsafe - add #Safety section to unsafe functions - add unsafe sub-features, like in devela THINK ----------- - Add some pixel fonts a short selection, and option to import - (receiving some kind of slice, typed or interpreted - (array from one type to another as long as they both implement X - (this pattern can be reused throughout all libera --- - implement From/To Char enum from devela (TODO) --- - [ ] bring functions from devela - strcount - buffer fmt - strings … ---- - WIP TRY add TryFrom/ From? - DESIGN Decide whether to fail, (TryFrom) or return From converting up until capacity. ------ - add new search methods using memchr ---- - add new NulTerminatedString types - crate - https://github.com/CAD97/cstr8/ - take ideas from other crates - https://crates.io/crates/fstr (conversion of just the right size?) ----- update Egc - [ ] impl TryFrom Egc (using string) for both static - … ops ---------- impl From<CharXX> for given string type aliases. ---- update unicode strings - new type `StaticNonSpecificString`. - make `StaticNonNulString` a type alias of `StaticNonSpecificString`. - [ ] TODO generalize strings even more: - `StaticNonSpecificString<const CHAR: &str, const CAP: usize> {}` - specialize StaticNonNulString as a type alias: `pub type StaticNonNulString<const CAP: usize> = StaticNonSpecificString<'\x00', CAP>;` ---- - pop_egc - push_egc (convenience) - push_utf8_bytes (from a byte slice) (impl from functions from_utf8? - pop utf8_bytes? ------ - graphemes? &[egc] ? ---- ## IDEAS chars: - [ ] new constructor for `Chars` trait and for concrete types. - add TryFrom<T: Chars>? or as a methods in chars? try_to_XXX - new char types e.g.: CharMath, CharBoxDrawing - those would be... enums :) - macro to generate an enum from a list of correspondences. - [ ] TODO: impl partialEq & partialOrd between all 4 char types - [ ] TODO: add more constants? - [ ] NUL strings: - add more alias string sizes? 96 (32×3), 192 (64×3) 384 (128 * 3) - [ ] MAYBE make counter_string a CounterString trait - [ ] impl over String, str, StaticStringU8, StaticNonNullString. - add non-unicode strings (sixbit?) less bit? with custom translation using custom tables. (link to a slice of the specific const-generic size) - generalize over unicode strings and non-unicode strings… single trait? ------ - TODO: add more methods? - escape_unicode - escape_debug - escape_default - wrap fns that returns iterators: to_lowercase, to_uppercase - https://doc.rust-lang.org/nightly/std/primitive.char.html#method.to_lowercase ---- - make tests, and examples. - impl push_str & try_push_str & try_push_str_complete for StaticStringU8 ---- add indent format - add own `Align` enum, & impl from fmt::Alignmnent, instead of using that. ------- - TextCell - TextGrid (via ladata/Grid2?) to libera type grid2d?? (recuperar cuadra como grid2d? - TextLine (rows, or - TextRope - traits - Ascii - Utf8 - Utf16 - struct Str<const BYTES: usize> {} // owns its buffer - --- alignment functions WIP examples - think about using cow ----- - THINK - no_std functions (how to group them) - a trait over String? ------- - THINK alternatives - dirty utf versions? - stateful struct to customize these things? ------- ## improve box drawing chars - separate lines - add dotted - add half - add thin to heavy - eight vertical & horizontal lines (U 15) - diagonal lines (U15) - add block elements - shades - half block shades - quadrants - sextants - eight vertical & horizontal blocks - eight vertical & horizontal blocks upper & right (u15) - corners - diagonal blocks (U15) - add a binary encoding ---- ----- ## alt. unicode-width - add an opinionated wrapper over unicode-width - maybe create traits depending on UnicodeWidthStr / UnicodeWidthChar - save custom tables for special symbols - for the rest of symbols, derive to unicode-width - deal with >2 width chars - deal with https://github.com/unicode-rs/unicode-width/issues/ ---- - From rational to select unicode char on filling -------------- I want to provide scaffolding for apunta bin + revela lib) a text buffer that refreshes, that can be analized, strings positioned… areas detected, layers... analisys at certain frequency / Hz --- - refactor cargo manifest ---- # functions beneficial to implement in a Rust library for text manipulation - https://chat.openai.com/c/17b13959-8073-42ef-bcf4-0b9ef59eb97c ----------- # rope - example crop alternatives - https://docs.rs/crop - https://docs.rs/jumprope - https://docs.rs/ropey/*/ropey/struct.Rope.html - https://docs.rs/any-rope/*/any_rope ---- # TODO - unicode columns based on width + override specially long characters - (perfect ad-hoc hash-map associated) - https://github.com/AldaronLau/unicode-columns/blob/stable/src/lib.rs ----- # UNICODE BLOCKS - https://docs.rs/unicode-blocks/0.1.5/unicode_blocks/struct.UnicodeBlock.html - `block` module. re-export crate. - desired API: 'a'.block() -> UnicodeBlock UnicodeBlock.name() UnicodeBlock.start() UnicodeBlock.end() UnicodeBlock.contains('a') ------ # UNICODE SEGMENTATION - https://unicode-rs.github.io/unicode-segmentation/unicode_segmentation/index.html ------ # mixed blitter - dankamongmen/notcurses#1223 ---- add collections of unicode characters with metadata - allow to support pixel ttf fonts, etc... - e.g.: dots: … ‥ . · etc… codepages - https://crates.io/crates/codepage-strings - https://crates.io/crates/oem-cp # IDEAS - recreate sixbit, in a more general way… choosing bw 64 & 128-bit codepages - https://crates.io/crates/sixbit/ -------- - no_std formatting? - https://doc.rust-lang.org/core/macro.format_args.html - https://doc.rust-lang.org/core/fmt/struct.Arguments.html -------- - ASCII utilities - see: https://doc.rust-lang.org/std/ascii/trait.AsciiExt.html#tymethod.eq_ignore_ascii_case --- - CASE utilities - https://stackoverflow.com/questions/38406793/why-is-capitalizing-the-first-letter-of-a-string-so-convoluted-in-rust # ISSUES - "Available on non-crate feature `safe` only." rust-lang/rust#43781 (comment) ## FONTS (TODO move to `trazas` crate?) - https://news.ycombinator.com/item?id=34689213 # LEARN FFI cstring, etc. - https://www.reddit.com/r/rust/comments/s3x1e3/const_const_u8/ - u8 is always 8-bits, but it's a mistake to use u8 rather than std::os::raw::c_char # LEARN unicode - https://unicode.org/glossary/#byte_order_mark - https://en.wikipedia.org/wiki/Homoglyph#Unicode_homoglyphs # CRATES - https://github.com/bcmyers/num-format (also for numera, ladata…) - > https://docs.rs/memchr/2.5.0/memchr/ - https://crates.io/crates/texcore - https://crates.io/crates/tectonic :) a complete TeX/LaTeX engine - https://crates.io/crates/character-set (for inspiration) (source not in github) - https://docs.rs/crate/character-set/0.4.0/source/src/builtin/general_category.rs # WAITING for - https://doc.rust-lang.org/nightly/core/ascii/enum.Char.html - rust-lang/rust#110998 - rust-lang/rust#109814 string.leak for 1.72.0 ## DISCARDED IDEAS - [ ] remove Char types, move to devela? - better not, because I need good trait coupling…
Stabilizes the following API:
closes #102929
blocked by having an FCP for stabilization.