Stable Hash: Add feature, adjust CI, modify build.rs, add new API for accessing and setting the ahash seed in config.rs, make config.rs public

.github/workflows/build.yml

@@ -89,6 +89,37 @@ jobs:
         command: test
         args: ${{matrix.flags}}
 
+  nightly_features_build:
+    name: NightlyFeatureBuild
+    runs-on: ${{matrix.os}}
+    continue-on-error: ${{matrix.experimental}}
+    strategy:
+      matrix:
+        os: [ubuntu-latest]
+        flags:
+          - "--features stable_hash"
+        toolchain: [ nightly ]
+        experimental: [ false ]
+        include:
+          # smoketests for different toolchains
+          - { toolchain: nightly, os: windows-latest, experimental: false, flags: "" }
+          - { toolchain: nightly, os: macos-latest, experimental: false, flags: "" }
+      fail-fast: false
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Setup Toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: ${{matrix.toolchain}}
+          override: true
+      - name: Test
+        uses: actions-rs/cargo@v1
+        with:
+          command: test
+          args: ${{matrix.flags}}
+
+
   # no-std builds are a bit more extensive to test
   no_std_build:
     name: NoStdBuild

.gitignore

@@ -8,3 +8,6 @@ Rhai.toml
 **/*.bat
 doc/rhai-sync.json
 doc/rhai.json
+.idea/
+.idea
+.idea/*

Cargo.toml

@@ -63,6 +63,7 @@ unicode-xid-ident = ["unicode-xid"] # allow Unicode Standard Annex #31 for ident
 metadata = ["serde", "serde_json", "rhai_codegen/metadata", "smartstring/serde"] # enable exporting functions metadata
 internals = []                  # expose internal data structures
 debugging = ["internals"]       # enable debugging
+stable_hash = ["std"]
 serde = ["dep:serde", "smartstring/serde", "smallvec/serde"] # implement serde for rhai types
 
 # compiling for no-std

build.rs

@@ -8,20 +8,21 @@ fn main() {
     // Tell Cargo that if the given environment variable changes, to rerun this build script.
     println!("cargo:rerun-if-changed=build.template");
     println!("cargo:rerun-if-env-changed=RHAI_AHASH_SEED");
+    if !cfg!(feature = "stable_hash") {
+        let mut contents = String::new();
 
-    let mut contents = String::new();
+        File::open("build.template")
+            .expect("cannot open `build.template`")
+            .read_to_string(&mut contents)
+            .expect("cannot read from `build.template`");
 
-    File::open("build.template")
-        .expect("cannot open `build.template`")
-        .read_to_string(&mut contents)
-        .expect("cannot read from `build.template`");
+        let seed = env::var("RHAI_AHASH_SEED").map_or_else(|_| "None".into(), |s| format!("Some({s})"));
 
-    let seed = env::var("RHAI_AHASH_SEED").map_or_else(|_| "None".into(), |s| format!("Some({s})"));
+        contents = contents.replace("{{AHASH_SEED}}", &seed);
 
-    contents = contents.replace("{{AHASH_SEED}}", &seed);
-
-    File::create("src/config.rs")
-        .expect("cannot create `config.rs`")
-        .write(contents.as_bytes())
-        .expect("cannot write to `config.rs`");
+        File::create("src/config.rs")
+            .expect("cannot create `config.rs`")
+            .write_all(contents.as_bytes())
+            .expect("cannot write to `config.rs`");
+    }
 }

build.template

@@ -1,7 +1,60 @@
-//! Configuration settings for this Rhai build
-//!
-//! This file is auto-generated from `build.template`
+#[cfg(feature = "stable_hash")]
+use core::cell::OnceCell;
 
+// [236,800,954,213], haha funny yume nikki reference
+
+#[cfg(not(feature = "stable_hash"))]
 /// Fixed hashing seeds for stable hashing.
+///
 /// Set to [`None`] to disable stable hashing.
-pub const AHASH_SEED: Option<[u64; 4]> = {{AHASH_SEED}};
+///
+/// See [`set_rhai_ahash_seed`] for more.
+///
+/// You can also set this at compile time by disabling `stable_hash` and setting the `RHAI_AHASH_SEED`
+/// environment variable instead.
+///
+/// E.g. `env RHAI_AHASH_SEED ="[236,800,954,213]"`
+const AHASH_SEED: Option<[u64; 4]> = {{AHASH_SEED}};
+#[cfg(feature = "stable_hash")]
+/// Fixed hashing seeds for stable hashing.
+///
+/// Set to [`None`] to disable stable hashing.
+///
+/// See [`set_rhai_ahash_seed`] for more.
+///
+/// You can also set this at compile time by disabling `stable_hash` and setting the `RHAI_AHASH_SEED`
+/// environment variable instead.
+///
+/// E.g. `env RHAI_AHASH_SEED ="[236,800,954,213]"`
+static AHASH_SEED: OnceCell<Option<[u64; 4]>> = OnceCell::new();
+
+#[cfg(feature = "stable_hash")]
+#[doc(cfg(feature = "stable_hash"))]
+/// Sets the Rhai Ahash seed. This is used to hash functions and the like.
+///
+/// This is a global variable, and thus will affect every Rhai instance.
+/// This should not be used _unless_ you know you need it.
+///
+/// **WARNING**:
+/// - You can only call this function **ONCE** for the whole of your program execution.
+/// - You should gracefully handle the `Err(())`.
+/// - You **MUST** call this before **ANY** Rhai operation occurs (e.g. creating an [`Engine`]).
+pub fn set_rhai_ahash_seed(new_seed: Option<[u64; 4]>) -> Result<(), Option<[u64; 4]>> {
+    AHASH_SEED.set(new_seed)
+}
+
+#[cfg(feature = "stable_hash")]
+/// Gets the current Rhai Ahash Seed.
+///
+/// See [`set_rhai_ahash_seed`] for more.
+pub fn get_rhai_ahash_seed() -> Option<[u64; 4]> {
+    AHASH_SEED.get().map(|x| *x).flatten()
+}
+
+#[cfg(not(feature = "stable_hash"))]
+/// Gets the current Rhai Ahash Seed.
+///
+/// See [`AHASH_SEED`] and [`set_rhai_ahash_seed`] for more.
+pub fn get_rhai_ahash_seed() -> Option<[u64; 4]> {
+    AHASH_SEED
+}

src/config.rs

@@ -1,7 +1,50 @@
-//! Configuration settings for this Rhai build
+//! Fixed hashing seeds for stable hashing.
 //!
-//! This file is auto-generated from `build.template`
+//! Set to [`None`] to disable stable hashing.
+//!
+//! See [`set_rhai_ahash_seed`] for more.
+//!
+//! Alternatively, You can also set this at compile time by disabling `stable_hash` and setting the `RHAI_AHASH_SEED`
+//! environment variable instead.
+//!
+//! E.g. `env RHAI_AHASH_SEED ="[236,800,954,213]"`
+// [236,800,954,213], haha funny yume nikki reference epic uboachan face numberworld nexus moment 100
 
-/// Fixed hashing seeds for stable hashing.
-/// Set to [`None`] to disable stable hashing.
-pub const AHASH_SEED: Option<[u64; 4]> = None;
+#[cfg(feature = "stable_hash")]
+use std::sync::OnceLock;
+
+#[cfg(not(feature = "stable_hash"))]
+const AHASH_SEED: Option<[u64; 4]> = None;
+#[cfg(feature = "stable_hash")]
+static AHASH_SEED: OnceLock<Option<[u64; 4]>> = OnceLock::new();
+
+#[cfg(feature = "stable_hash")]
+// #[doc(cfg(feature = "stable_hash"))]
+/// Sets the Rhai Ahash seed. This is used to hash functions and the like.
+///
+/// This is a global variable, and thus will affect every Rhai instance.
+/// This should not be used _unless_ you know you need it.
+///
+/// **WARNING**:
+/// - You can only call this function **ONCE** for the whole of your program execution.
+/// - You should gracefully handle the `Err(())`.
+/// - You **MUST** call this before **ANY** Rhai operation occurs (e.g. creating an [`Engine`]).
+pub fn set_rhai_ahash_seed(new_seed: Option<[u64; 4]>) -> Result<(), Option<[u64; 4]>> {
+    AHASH_SEED.set(new_seed)
+}
+
+#[cfg(feature = "stable_hash")]
+/// Gets the current Rhai Ahash Seed.
+///
+/// See [`set_rhai_ahash_seed`] for more.
+pub fn get_rhai_ahash_seed() -> Option<[u64; 4]> {
+    AHASH_SEED.get().map(|x| *x).flatten()
+}
+
+#[cfg(not(feature = "stable_hash"))]
+/// Gets the current Rhai Ahash Seed.
+///
+/// See [`AHASH_SEED`] and [`set_rhai_ahash_seed`] for more.
+pub fn get_rhai_ahash_seed() -> Option<[u64; 4]> {
+    AHASH_SEED
+}

src/func/hashing.rs

@@ -77,7 +77,7 @@ impl BuildHasher for StraightHasherBuilder {
 #[inline(always)]
 #[must_use]
 pub fn get_hasher() -> ahash::AHasher {
-    match config::AHASH_SEED {
+    match config::get_rhai_ahash_seed() {
         Some([seed1, seed2, seed3, seed4]) if seed1 | seed2 | seed3 | seed4 != 0 => {
             ahash::RandomState::with_seeds(seed1, seed2, seed3, seed4).build_hasher()
         }

src/lib.rs

@@ -71,6 +71,8 @@
 #![allow(clippy::negative_feature_names)]
 #![allow(clippy::module_inception)]
 
+#![cfg_attr(feature = "stable_hash", feature(once_cell))]
+
 #[cfg(feature = "no_std")]
 extern crate alloc;
 
@@ -83,7 +85,7 @@ use std::prelude::v1::*;
 // Internal modules
 mod api;
 mod ast;
-mod config;
+pub mod config;
 mod engine;
 mod eval;
 mod func;