Release 2.12.0

.github/workflows/ci.yml

@@ -17,7 +17,7 @@ jobs:
     strategy:
       matrix:
         include:
-          - rust: 1.63.0 # MSRV
+          - rust: 1.82.0 # MSRV
             features:
           - rust: stable
             features: arbitrary
@@ -40,13 +40,8 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/cache@v4
-        if: matrix.rust == '1.63.0'
-        with:
-          path: ~/.cargo/registry/index
-          key: cargo-git-index
       - name: Lock MSRV-compatible dependencies
-        if: matrix.rust == '1.63.0'
+        if: matrix.rust == '1.82.0'
         env:
           CARGO_RESOLVER_INCOMPATIBLE_RUST_VERSIONS: fallback
         # Note that this uses the runner's pre-installed stable cargo
@@ -77,20 +72,15 @@ jobs:
     strategy:
       matrix:
         include:
-          - rust: 1.63.0
+          - rust: 1.82.0
             target: thumbv6m-none-eabi
           - rust: stable
             target: thumbv6m-none-eabi
 
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/cache@v4
-        if: matrix.rust == '1.63.0'
-        with:
-          path: ~/.cargo/registry/index
-          key: cargo-git-index
       - name: Lock MSRV-compatible dependencies
-        if: matrix.rust == '1.63.0'
+        if: matrix.rust == '1.82.0'
         env:
           CARGO_RESOLVER_INCOMPATIBLE_RUST_VERSIONS: fallback
         # Note that this uses the runner's pre-installed stable cargo
@@ -123,20 +113,18 @@ jobs:
       - uses: taiki-e/install-action@v2
         with:
           tool: cargo-nextest
+        if: github.event_name == 'merge_group'
       - run: cargo miri nextest run
+        if: github.event_name == 'merge_group'
       - run: cargo miri test --doc
 
   minimal-versions:
     name: Check MSRV and minimal-versions
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/cache@v4
-        with:
-          path: ~/.cargo/registry/index
-          key: cargo-git-index
       - uses: dtolnay/rust-toolchain@nightly
-      - uses: dtolnay/rust-toolchain@1.63.0 # MSRV
+      - uses: dtolnay/rust-toolchain@1.82.0 # MSRV
       - uses: taiki-e/install-action@v2
         with:
           tool: cargo-hack

Cargo.toml

@@ -1,20 +1,21 @@
 [package]
 name = "indexmap"
 edition = "2021"
-version = "2.11.4"
+version = "2.12.0"
 documentation = "https://docs.rs/indexmap/"
 repository = "https://github.com/indexmap-rs/indexmap"
 license = "Apache-2.0 OR MIT"
 description = "A hash table with consistent order and fast iteration."
 keywords = ["hashmap", "no_std"]
 categories = ["data-structures", "no-std"]
-rust-version = "1.63"
+rust-version = "1.82"
 
 [lib]
 bench = false
 
 [dependencies]
 equivalent = { version = "1.0", default-features = false }
+hashbrown = { version = "0.16", default-features = false }
 
 arbitrary = { version = "1.0", optional = true, default-features = false }
 quickcheck = { version = "1.0", optional = true, default-features = false }
@@ -25,10 +26,6 @@ sval = { version = "2", optional = true, default-features = false }
 # deprecated: use borsh's "indexmap" feature instead.
 borsh = { version = "1.2", optional = true, default-features = false }
 
-[dependencies.hashbrown]
-version = ">= 0.15.0, < 0.17.0"
-default-features = false
-
 # serde v1.0.220 is the first version that released with `serde_core`.
 # This is required to avoid conflict with other `serde` users which may require an older version.
 [target.'cfg(any())'.dependencies]
@@ -64,5 +61,16 @@ rustdoc-args = ["--cfg", "docsrs"]
 [workspace]
 members = ["test-nostd", "test-serde", "test-sval"]
 
+[lints.rust]
+private-bounds = "deny"
+private-interfaces = "deny"
+unnameable-types = "deny"
+unreachable-pub = "deny"
+
+# We *mostly* avoid unsafe code, but there are a few fine-grained cases allowed
+unsafe-code = "deny"
+
+rust-2018-idioms = "warn"
+
 [lints.clippy]
 style = "allow"

README.md

@@ -3,7 +3,7 @@
 [![build status](https://github.com/indexmap-rs/indexmap/actions/workflows/ci.yml/badge.svg?branch=main)](https://github.com/indexmap-rs/indexmap/actions)
 [![crates.io](https://img.shields.io/crates/v/indexmap.svg)](https://crates.io/crates/indexmap)
 [![docs](https://docs.rs/indexmap/badge.svg)](https://docs.rs/indexmap)
-[![rustc](https://img.shields.io/badge/rust-1.63%2B-orange.svg)](https://img.shields.io/badge/rust-1.63%2B-orange.svg)
+[![rustc](https://img.shields.io/badge/rust-1.82%2B-orange.svg)](https://img.shields.io/badge/rust-1.82%2B-orange.svg)
 
 A pure-Rust hash table which preserves (in a limited sense) insertion order.
 

RELEASES.md

@@ -1,5 +1,13 @@
 # Releases
 
+## 2.12.0 (2025-10-17)
+
+- **MSRV**: Rust 1.82.0 or later is now required.
+- Updated the `hashbrown` dependency to 0.16 alone.
+- Error types now implement `core::error::Error`.
+- Added `pop_if` methods to `IndexMap` and `IndexSet`, similar to the
+  method for `Vec` added in Rust 1.86.
+
 ## 2.11.4 (2025-09-18)
 
 - Updated the `hashbrown` dependency to a range allowing 0.15 or 0.16.

benches/bench.rs

@@ -5,10 +5,10 @@ extern crate test;
 use fnv::FnvHasher;
 use std::hash::BuildHasherDefault;
 use std::hash::Hash;
+use std::hint::black_box;
 use std::sync::LazyLock;
 type FnvBuilder = BuildHasherDefault<FnvHasher>;
 
-use test::black_box;
 use test::Bencher;
 
 use indexmap::IndexMap;

benches/faststring.rs

@@ -33,8 +33,10 @@ impl<'a, S> From<&'a S> for &'a OneShot<str>
 where
     S: AsRef<str>,
 {
+    #[allow(unsafe_code)]
     fn from(s: &'a S) -> Self {
         let s: &str = s.as_ref();
+        // SAFETY: OneShot is a `repr(transparent)` wrapper
         unsafe { &*(s as *const str as *const OneShot<str>) }
     }
 }

src/borsh.rs

@@ -3,7 +3,6 @@
 use alloc::vec::Vec;
 use core::hash::BuildHasher;
 use core::hash::Hash;
-use core::mem::size_of;
 
 use borsh::error::ERROR_ZST_FORBIDDEN;
 use borsh::io::{Error, ErrorKind, Read, Result, Write};

src/lib.rs

@@ -1,6 +1,3 @@
-// We *mostly* avoid unsafe code, but `Slice` allows it for DST casting.
-#![deny(unsafe_code)]
-#![warn(rust_2018_idioms)]
 #![no_std]
 
 //! [`IndexMap`] is a hash table where the iteration order of the key-value
@@ -60,7 +57,7 @@
 //! ### Alternate Hashers
 //!
 //! [`IndexMap`] and [`IndexSet`] have a default hasher type
-//! [`S = RandomState`][std::collections::hash_map::RandomState],
+//! [`S = RandomState`][std::hash::RandomState],
 //! just like the standard `HashMap` and `HashSet`, which is resistant to
 //! HashDoS attacks but not the most performant. Type aliases can make it easier
 //! to use alternate hashers:
@@ -79,7 +76,7 @@
 //!
 //! ### Rust Version
 //!
-//! This version of indexmap requires Rust 1.63 or later.
+//! This version of indexmap requires Rust 1.82 or later.
 //!
 //! The indexmap 2.x release series will use a carefully considered version
 //! upgrade policy, where in a later 2.x version, we will raise the minimum
@@ -255,9 +252,7 @@ impl core::fmt::Display for TryReserveError {
     }
 }
 
-#[cfg(feature = "std")]
-#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
-impl std::error::Error for TryReserveError {}
+impl core::error::Error for TryReserveError {}
 
 // NOTE: This is copied from the slice module in the std lib.
 /// The error type returned by [`get_disjoint_indices_mut`][`IndexMap::get_disjoint_indices_mut`].
@@ -285,6 +280,4 @@ impl core::fmt::Display for GetDisjointMutError {
     }
 }
 
-#[cfg(feature = "std")]
-#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
-impl std::error::Error for GetDisjointMutError {}
+impl core::error::Error for GetDisjointMutError {}

src/map.rs

@@ -28,14 +28,14 @@ pub use crate::rayon::map as rayon;
 
 use ::core::cmp::Ordering;
 use ::core::fmt;
-use ::core::hash::{BuildHasher, Hash, Hasher};
+use ::core::hash::{BuildHasher, Hash};
 use ::core::mem;
 use ::core::ops::{Index, IndexMut, RangeBounds};
 use alloc::boxed::Box;
 use alloc::vec::Vec;
 
 #[cfg(feature = "std")]
-use std::collections::hash_map::RandomState;
+use std::hash::RandomState;
 
 pub(crate) use self::core::{ExtractCore, IndexMapCore};
 use crate::util::{third, try_simplify_range};
@@ -813,9 +813,8 @@ where
     S: BuildHasher,
 {
     pub(crate) fn hash<Q: ?Sized + Hash>(&self, key: &Q) -> HashValue {
-        let mut h = self.hash_builder.build_hasher();
-        key.hash(&mut h);
-        HashValue(h.finish() as usize)
+        let h = self.hash_builder.hash_one(key);
+        HashValue(h as usize)
     }
 
     /// Return `true` if an equivalent to `key` exists in the map.
@@ -1826,10 +1825,11 @@ where
         // Otherwise reserve half the hint (rounded up), so the map
         // will only resize twice in the worst case.
         let iter = iterable.into_iter();
+        let (lower_len, _) = iter.size_hint();
         let reserve = if self.is_empty() {
-            iter.size_hint().0
+            lower_len
         } else {
-            (iter.size_hint().0 + 1) / 2
+            lower_len.div_ceil(2)
         };
         self.reserve(reserve);
         iter.for_each(move |(k, v)| {

src/map/core.rs

@@ -47,15 +47,15 @@ struct RefMut<'a, K, V> {
 }
 
 #[inline(always)]
-fn get_hash<K, V>(entries: &[Bucket<K, V>]) -> impl Fn(&usize) -> u64 + '_ {
+fn get_hash<K, V>(entries: &[Bucket<K, V>]) -> impl Fn(&usize) -> u64 + use<'_, K, V> {
     move |&i| entries[i].hash.get()
 }
 
 #[inline]
 fn equivalent<'a, K, V, Q: ?Sized + Equivalent<K>>(
     key: &'a Q,
     entries: &'a [Bucket<K, V>],
-) -> impl Fn(&usize) -> bool + 'a {
+) -> impl Fn(&usize) -> bool + use<'a, K, V, Q> {
     move |&i| Q::equivalent(key, &entries[i].key)
 }
 
@@ -111,7 +111,7 @@ where
 
 impl<K, V> IndexMapCore<K, V> {
     /// The maximum capacity before the `entries` allocation would exceed `isize::MAX`.
-    const MAX_ENTRIES_CAPACITY: usize = (isize::MAX as usize) / mem::size_of::<Bucket<K, V>>();
+    const MAX_ENTRIES_CAPACITY: usize = (isize::MAX as usize) / size_of::<Bucket<K, V>>();
 
     #[inline]
     pub(crate) const fn new() -> Self {