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# 2.6.0
## What's Changed
* Sync CHANGELOG.md with github release notes by @dextero in https://github.com/bitflags/bitflags/pull/402
* Bump minimum declared versions of dependencies by @dextero in https://github.com/bitflags/bitflags/pull/404
* chore(deps): bump serde_derive and bytemuck versions by @joshka in https://github.com/bitflags/bitflags/pull/405
* Allow specifying outer attributes in impl mode by @KodrAus in https://github.com/bitflags/bitflags/pull/411
## New Contributors
# 2.5.0
## What's Changed
* Support truncating or strict-named variants of parsing and formatting by @KodrAus in https://github.com/bitflags/bitflags/pull/400
## New Contributors
# 2.4.2
## What's Changed
* Cargo.toml: Anchor excludes to root of the package by @jamessan in https://github.com/bitflags/bitflags/pull/387
* Add support for impl mode structs to be repr(packed) by @GnomedDev in https://github.com/bitflags/bitflags/pull/388
* Remove old `unused_tuple_struct_fields` lint by @dtolnay in https://github.com/bitflags/bitflags/pull/393
## New Contributors
# 2.4.1
## What's Changed
# 2.4.0
## What's Changed
* Update smoke test to verify all Clippy and rustc lints by @MitMaro in https://github.com/bitflags/bitflags/pull/374
## New Contributors
# 2.3.3
## Changes to `-=`
The `-=` operator was incorrectly changed to truncate bits that didn't correspond to valid flags in `2.3.0`. This has
been fixed up so it once again behaves the same as `-` and `difference`.
## Changes to `!`
The `!` operator previously called `Self::from_bits_truncate`, which would truncate any bits that only partially
overlapped with a valid flag. It will now use `bits & Self::all().bits()`, so any bits that overlap any bits
specified by any flag will be respected. This is unlikely to have any practical implications, but enables defining
a flag like `const ALL = !0` as a way to signal that any bit pattern is a known set of flags.
## Changes to formatting
Zero-valued flags will never be printed. You'll either get `0x0` for empty flags using debug formatting, or the
set of flags with zero-valued flags omitted for others.
Composite flags will no longer be redundantly printed if there are extra bits to print at the end that don't correspond
to a valid flag.
## What's Changed
* Fix up incorrect sub assign behavior and other cleanups by @KodrAus in https://github.com/bitflags/bitflags/pull/366
# 2.3.2
## What's Changed
* [doc] [src/lib.rs] delete redundant path prefix by @OccupyMars2025 in https://github.com/bitflags/bitflags/pull/361
## New Contributors
# 2.3.1
## What's Changed
# 2.3.0
## Major changes
### `BitFlags` trait deprecated in favor of `Flags` trait
This release introduces the `Flags` trait and deprecates the `BitFlags` trait. These two traits are semver compatible so if you have public API code depending on `BitFlags` you can move to `Flags` without breaking end-users. This is possible because the `BitFlags` trait was never publicly implementable, so it now carries `Flags` as a supertrait. All implementations of `Flags` additionally implement `BitFlags`.
The `Flags` trait is a publicly implementable version of the old `BitFlags` trait. The original `BitFlags` trait carried some macro baggage that made it difficult to implement, so a new `Flags` trait has been introduced as the _One True Trait_ for interacting with flags types generically. See the the `macro_free` and `custom_derive` examples for more details.
### `Bits` trait publicly exposed
The `Bits` trait for the underlying storage of flags values is also now publicly implementable. This lets you define your own exotic backing storage for flags. See the `custom_bits_type` example for more details.
## What's Changed
* Use explicit hashes for actions steps by @KodrAus in https://github.com/bitflags/bitflags/pull/350
* Support ejecting flags types from the bitflags macro by @KodrAus in https://github.com/bitflags/bitflags/pull/351
# 2.2.1
## What's Changed
* Refactor attribute filtering to apply per-flag by @KodrAus in https://github.com/bitflags/bitflags/pull/345
# 2.2.0
## What's Changed
* add docs to describe the behavior of multi-bit flags by @nicholasbishop in https://github.com/bitflags/bitflags/pull/340
* Add a top-level macro for filtering attributes by @KodrAus in https://github.com/bitflags/bitflags/pull/341
## New Contributors
# 2.1.0
## What's Changed
* Add docs for the internal Field0 and examples of formatting/parsing by @KodrAus in https://github.com/bitflags/bitflags/pull/328
* Fix up missing docs for consts within consts by @KodrAus in https://github.com/bitflags/bitflags/pull/330
* Ignore clippy lint in generated code by @Jake-Shadle in https://github.com/bitflags/bitflags/pull/331
## New Contributors
# 2.0.2
## What's Changed
* Fix up missing isize and usize Bits impls by @KodrAus in https://github.com/bitflags/bitflags/pull/321
# 2.0.1
## What's Changed
* Fix formatting of multi-bit flags with partial overlap by @KodrAus in https://github.com/bitflags/bitflags/pull/316
## New Contributors
# 2.0.0
## Major changes
This release includes some major changes over `1.x`. If you use `bitflags!` types in your public API then upgrading this library may cause breakage in your downstream users.
### ⚠️ Serialization
You'll need to add the `serde` Cargo feature in order to `#[derive(Serialize, Deserialize)]` on your generated flags types:
```rust
bitflags! {
#[derive(Serialize, Deserialize)]
#[serde(transparent)]
pub struct Flags: T {
..
}
}
```
where `T` is the underlying bits type you're using, such as `u32`.
The default serialization format with `serde` **has changed** if you `#[derive(Serialize, Deserialize)]` on your generated flags types. It will now use a formatted string for human-readable formats and the underlying bits type for compact formats.
### ⚠️ Traits
Generated flags types now derive fewer traits. If you need to maintain backwards compatibility, you can derive the following yourself:
```rust
#[derive(PartialEq, Eq, PartialOrd, Ord, Hash, Debug, Clone, Copy)]
```
### ⚠️ Methods
The unsafe `from_bits_unchecked` method is now a safe `from_bits_retain` method.
You can add the following method to your generated types to keep them compatible:
```rust
#[deprecated = "use the safe `from_bits_retain` method instead"]
pub unsafe fn from_bits_unchecked(bits: T) -> Self {
Self::from_bits_retain(bits)
}
```
where `T` is the underlying bits type you're using, such as `u32`.
### ⚠️ `.bits` field
You can now use the `.bits()` method instead of the old `.bits`.
The representation of generated flags types has changed from a struct with the single field `bits` to a newtype.
## What's Changed
* Add a hidden trait to discourage manual impls of BitFlags by @KodrAus in https://github.com/bitflags/bitflags/pull/261
* Fix a typo in the generated documentation by @wackbyte in https://github.com/bitflags/bitflags/pull/271
* Iterator over all the enabled options by @arturoc in https://github.com/bitflags/bitflags/pull/278
* from_bits_(truncate) fail with composite flags by @arturoc in https://github.com/bitflags/bitflags/pull/276
* expose bitflags iters using nameable types by @KodrAus in https://github.com/bitflags/bitflags/pull/286
* Support creating flags from their names by @KodrAus in https://github.com/bitflags/bitflags/pull/287
* Add missing "if" to contains doc-comment in traits.rs by @rusty-snake in https://github.com/bitflags/bitflags/pull/291
* Add a parser for flags formatted as bar-separated-values by @KodrAus in https://github.com/bitflags/bitflags/pull/297
* Use strip_prefix instead of starts_with + slice by @QuinnPainter in https://github.com/bitflags/bitflags/pull/301
* feat: Add minimum permissions to rust.yml workflow by @gabibguti in https://github.com/bitflags/bitflags/pull/305
## New Contributors
# 2.0.0-rc.3
## What's Changed
* Use strip_prefix instead of starts_with + slice by @QuinnPainter in https://github.com/bitflags/bitflags/pull/301
## New Contributors
# 2.0.0-rc.2
## Changes to `serde` serialization
**⚠️ NOTE ⚠️** This release changes the default serialization you'll get if you `#[derive(Serialize, Deserialize)]`
on your generated flags types. It will now use a formatted string for human-readable formats and the underlying bits
type for compact formats.
To keep the old behavior, see the [`bitflags-serde-legacy`](https://github.com/KodrAus/bitflags-serde-legacy) library.
## What's Changed
* Add missing "if" to contains doc-comment in traits.rs by @rusty-snake in https://github.com/bitflags/bitflags/pull/291
* Add a parser for flags formatted as bar-separated-values by @KodrAus in https://github.com/bitflags/bitflags/pull/297
## New Contributors
# 2.0.0-rc.1
This is a big release including a few years worth of work on a new `BitFlags` trait, iteration, and better macro organization for future extensibility.
## What's Changed
* Add a hidden trait to discourage manual impls of BitFlags by @KodrAus in https://github.com/bitflags/bitflags/pull/261
* Fix a typo in the generated documentation by @wackbyte in https://github.com/bitflags/bitflags/pull/271
* Iterator over all the enabled options by @arturoc in https://github.com/bitflags/bitflags/pull/278
* from_bits_(truncate) fail with composite flags by @arturoc in https://github.com/bitflags/bitflags/pull/276
* expose bitflags iters using nameable types by @KodrAus in https://github.com/bitflags/bitflags/pull/286
* Support creating flags from their names by @KodrAus in https://github.com/bitflags/bitflags/pull/287
## New Contributors
# 1.3.2
- Allow `non_snake_case` in generated flags types ([#256])
# 1.3.1
- Revert unconditional `#[repr(transparent)]` ([#252])
# 1.3.0 (yanked)
**This release bumps the Minimum Supported Rust Version to `1.46.0`**
- Add `#[repr(transparent)]` ([#187])
- End `empty` doc comment with full stop ([#202])
- Fix typo in crate root docs ([#206])
- Document from_bits_unchecked unsafety ([#207])
- Let `is_all` ignore extra bits ([#211])
- Allows empty flag definition ([#225])
- Making crate accessible from std ([#227])
- Make `from_bits` a const fn ([#229])
- Allow multiple bitflags structs in one macro invocation ([#235])
- Add named functions to perform set operations ([#244])
- Fix typos in method docs ([#245])
- Modernization of the `bitflags` macro to take advantage of newer features and 2018 idioms ([#246])
- Fix regression (in an unreleased feature) and simplify tests ([#247])
- Use `Self` and fix bug when overriding `stringify!` ([#249])
# 1.2.1
- Remove extraneous `#[inline]` attributes ([#194])
# 1.2.0
- Fix typo: {Lower, Upper}Exp - {Lower, Upper}Hex ([#183])
- Add support for "unknown" bits ([#188])
# 1.1.0
This is a re-release of `1.0.5`, which was yanked due to a bug in the RLS.
# 1.0.5
- Use compiletest_rs flags supported by stable toolchain ([#171])
- Put the user provided attributes first ([#173])
- Make bitflags methods `const` on newer compilers ([#175])
# 1.0.4
- Support Rust 2018 style macro imports ([#165])
```rust
use bitflags::bitflags;
```
# 1.0.3
- Improve zero value flag handling and documentation ([#157])
# 1.0.2
- 30% improvement in compile time of bitflags crate ([#156])
- Documentation improvements ([#153])
- Implementation cleanup ([#149])
# 1.0.1
- Add support for `pub(restricted)` specifier on the bitflags struct ([#135])
- Optimize performance of `all()` when called from a separate crate ([#136])
# 1.0.0
- **[breaking change]** Macro now generates [associated constants](https://doc.rust-lang.org/reference/items.html#associated-constants) ([#24])
- **[breaking change]** Minimum supported version is Rust **1.20**, due to usage of associated constants
- After being broken in 0.9, the `#[deprecated]` attribute is now supported again ([#112])
- Other improvements to unit tests and documentation ([#106] and [#115])
## How to update your code to use associated constants
Assuming the following structure definition:
```rust
bitflags! {
struct Something: u8 {
const FOO = 0b01,
const BAR = 0b10
}
}
```
In 0.9 and older you could do:
```rust
let x = FOO.bits | BAR.bits;
```
Now you must use:
```rust
let x = Something::FOO.bits | Something::BAR.bits;
```
# 0.9.1
- Fix the implementation of `Formatting` traits when other formatting traits were present in scope ([#105])
# 0.9.0
- **[breaking change]** Use struct keyword instead of flags to define bitflag types ([#84])
- **[breaking change]** Terminate const items with semicolons instead of commas ([#87])
- Implement the `Hex`, `Octal`, and `Binary` formatting traits ([#86])
- Printing an empty flag value with the `Debug` trait now prints "(empty)" instead of nothing ([#85])
- The `bitflags!` macro can now be used inside of a fn body, to define a type local to that function ([#74])
# 0.8.2
- Update feature flag used when building bitflags as a dependency of the Rust toolchain
# 0.8.1
- Allow bitflags to be used as a dependency of the Rust toolchain
# 0.8.0
- Add support for the experimental `i128` and `u128` integer types ([#57])
- Add set method: `flags.set(SOME_FLAG, true)` or `flags.set(SOME_FLAG, false)` ([#55])
This may break code that defines its own set method
# 0.7.1
*(yanked)*
# 0.7.0
- Implement the Extend trait ([#49])
- Allow definitions inside the `bitflags!` macro to refer to items imported from other modules ([#51])
# 0.6.0
- The `no_std` feature was removed as it is now the default
- The `assignment_operators` feature was remove as it is now enabled by default
- Some clippy suggestions have been applied