From 941b717dbd3e2dd2e8020b02ed6a092d13ba50b7 Mon Sep 17 00:00:00 2001 From: Tobias Bieniek Date: Mon, 15 Jun 2026 14:32:17 +0200 Subject: [PATCH 1/4] Rewrite README with data format and usage docs Document the per-crate TOML layout, how to build and consume `build/all.json`, the inclusion criteria, and the dataset's origin in crates.io. --- README.md | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 67 insertions(+), 1 deletion(-) diff --git a/README.md b/README.md index 630adf1..ec7871e 100644 --- a/README.md +++ b/README.md @@ -1,2 +1,68 @@ # std-replacement-data -Curated dataset of standard-library replacements for crates, surfaced on crates.io + +A curated dataset of Rust crates whose functionality is now available in the +standard library. crates.io reads it to point out when `std` already covers +what the crate provides and where to find the equivalent API. + +Every entry is a checkable factual statement about `std`, never an opinion about +a competing crate. + +## Data + +Each crate lives in its own file at `data/.toml`: + +```toml +description = """ +The standard library provides `std::sync::LazyLock` (stable since Rust 1.80), \ +which lets you replace the `lazy_static!` macro with a plain `static`. +""" +url = "https://doc.rust-lang.org/std/sync/struct.LazyLock.html" +``` + +- `description`: Markdown explaining the replacement. It must cite the stable + `std` API(s) and the Rust version(s) that stabilized them. +- `url`: a docs or release-notes link, shown as a "Learn more" link. + +## Consuming the data + +`build.py` bundles every TOML file into a single `build/all.json`, keyed by +crate name. That file is published to GitHub Pages: + +``` +https://rust-lang.github.io/std-replacement-data/all.json +``` + +To build it locally (Python 3.11+ for `tomllib`): + +```sh +python3 build.py +``` + +## What qualifies + +Standard-library replacements only. The dataset deliberately avoids "prefer this +nicer crate instead" recommendations. + +Two kinds of entries qualify: + +- **Full**: the crate's functionality is entirely available through a stable + `std` API. +- **Partial**: the bulk of the crate's common use case has moved to `std`, but + not all of it. The `description` must spell out what is still missing. + +Coverage is judged by the dominant use case. If only a small slice of a crate's +purpose lives in `std`, it does not qualify. `itertools` is the canonical +exclusion: a handful of its adaptors have `std` equivalents, but the crate as a +whole is not replaced. + +Before an entry lands, the maintainer(s) of the flagged crate get a window to +weigh in, either to object or to show that the replacement is less complete than +claimed, in which case the entry becomes partial or is dropped. + +## Origin + +The data started out inline in crates.io and moved here so other tools can +consume it too. See [rust-lang/crates.io#13855][pr] for the original +implementation. + +[pr]: https://github.com/rust-lang/crates.io/pull/13855 From 6cc873ac719357e7ce1457b02b73c4bc3c60a69b Mon Sep 17 00:00:00 2001 From: Tobias Bieniek Date: Mon, 15 Jun 2026 14:41:31 +0200 Subject: [PATCH 2/4] Add dual MIT/Apache-2.0 license Licensed under `MIT OR Apache-2.0`, matching the Rust ecosystem convention and crates.io, the source of the dataset. The README links to both license files. --- LICENSE-APACHE | 201 +++++++++++++++++++++++++++++++++++++++++++++++++ LICENSE-MIT | 25 ++++++ README.md | 7 ++ 3 files changed, 233 insertions(+) create mode 100644 LICENSE-APACHE create mode 100644 LICENSE-MIT diff --git a/LICENSE-APACHE b/LICENSE-APACHE new file mode 100644 index 0000000..16fe87b --- /dev/null +++ b/LICENSE-APACHE @@ -0,0 +1,201 @@ + Apache License + Version 2.0, January 2004 + http://www.apache.org/licenses/ + +TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION + +1. Definitions. + + "License" shall mean the terms and conditions for use, reproduction, + and distribution as defined by Sections 1 through 9 of this document. + + "Licensor" shall mean the copyright owner or entity authorized by + the copyright owner that is granting the License. + + "Legal Entity" shall mean the union of the acting entity and all + other entities that control, are controlled by, or are under common + control with that entity. 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IN NO EVENT +SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY +CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION +OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR +IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER +DEALINGS IN THE SOFTWARE. diff --git a/README.md b/README.md index ec7871e..0eb89ed 100644 --- a/README.md +++ b/README.md @@ -66,3 +66,10 @@ consume it too. See [rust-lang/crates.io#13855][pr] for the original implementation. [pr]: https://github.com/rust-lang/crates.io/pull/13855 + +## License + +Licensed under either of these: + +- Apache License, Version 2.0 ([LICENSE-APACHE](./LICENSE-APACHE) or ) +- MIT license ([LICENSE-MIT](./LICENSE-MIT) or ) From 568da2be62a63999dd41541fa875aed479951fcd Mon Sep 17 00:00:00 2001 From: Tobias Bieniek Date: Mon, 15 Jun 2026 15:11:37 +0200 Subject: [PATCH 3/4] Add CONTRIBUTING.md with the inclusion policy Move the inclusion policy out of the README into CONTRIBUTING.md, next to the contribution mechanics and the maintainer notice-and-comment step. The README now links there. --- CONTRIBUTING.md | 42 ++++++++++++++++++++++++++++++++++++++++++ README.md | 22 +++------------------- 2 files changed, 45 insertions(+), 19 deletions(-) create mode 100644 CONTRIBUTING.md diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md new file mode 100644 index 0000000..d7b7556 --- /dev/null +++ b/CONTRIBUTING.md @@ -0,0 +1,42 @@ +# Contributing + +Thank you for helping keep the std-replacement dataset accurate and useful. + +## Adding or changing an entry + +Each crate lives in its own file at `data/.toml` with two fields: + +- `description`: Markdown explaining the replacement. It must cite the stable + `std` API(s) and the Rust version(s) that stabilized them. +- `url`: a docs or release-notes link, shown as a "Learn more" link. + +Open one pull request per crate. `build.py` validates the dataset in CI, so run +it locally first: + +```sh +python3 build.py +``` + +## What qualifies + +Standard-library replacements only. The dataset deliberately avoids "prefer this +nicer crate instead" recommendations. Every entry is a checkable factual +statement about `std`, never an opinion about a competing crate. + +Two kinds of entries qualify: + +- **Full**: the crate's functionality is entirely available through a stable + `std` API. +- **Partial**: the bulk of the crate's common use case has moved to `std`, but + not all of it. The `description` must spell out what is still missing. + +Coverage is judged by the dominant use case. If only a small slice of a crate's +purpose lives in `std`, it does not qualify. `itertools` is the canonical +exclusion: a handful of its adaptors have `std` equivalents, but the crate as a +whole is not replaced. + +## Maintainer notice-and-comment + +Before an entry lands, the maintainer(s) of the flagged crate get a window to +weigh in, either to object or to show that the replacement is less complete than +claimed, in which case the entry becomes partial or is dropped. diff --git a/README.md b/README.md index 0eb89ed..215abfe 100644 --- a/README.md +++ b/README.md @@ -38,26 +38,10 @@ To build it locally (Python 3.11+ for `tomllib`): python3 build.py ``` -## What qualifies +## Contributing -Standard-library replacements only. The dataset deliberately avoids "prefer this -nicer crate instead" recommendations. - -Two kinds of entries qualify: - -- **Full**: the crate's functionality is entirely available through a stable - `std` API. -- **Partial**: the bulk of the crate's common use case has moved to `std`, but - not all of it. The `description` must spell out what is still missing. - -Coverage is judged by the dominant use case. If only a small slice of a crate's -purpose lives in `std`, it does not qualify. `itertools` is the canonical -exclusion: a handful of its adaptors have `std` equivalents, but the crate as a -whole is not replaced. - -Before an entry lands, the maintainer(s) of the flagged crate get a window to -weigh in, either to object or to show that the replacement is less complete than -claimed, in which case the entry becomes partial or is dropped. +New entries are welcome. See [CONTRIBUTING.md](./CONTRIBUTING.md) for what +qualifies as a std replacement and how to add one. ## Origin From 4aaf6d38736f85665d19b165858d3f6df9120770 Mon Sep 17 00:00:00 2001 From: Tobias Bieniek Date: Mon, 15 Jun 2026 15:23:53 +0200 Subject: [PATCH 4/4] Add crate ownership notice to README Name the crates.io team as maintainer and note that external consumers are welcome while the data and format may still change, per the Rust crate ownership policy. --- README.md | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/README.md b/README.md index 215abfe..ee8098b 100644 --- a/README.md +++ b/README.md @@ -7,6 +7,11 @@ what the crate provides and where to find the equivalent API. Every entry is a checkable factual statement about `std`, never an opinion about a competing crate. +> [!NOTE] +> This dataset is maintained by the crates.io team. Other tools are welcome to +> consume the published JSON. We aim to make it a stable data source, but until +> then its contents and format may still change without warning. + ## Data Each crate lives in its own file at `data/.toml`: