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Bump rand, mt19937; fix associated build failures #7800

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654 changes: 416 additions & 238 deletions Cargo.lock
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7 changes: 3 additions & 4 deletions Cargo.toml
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Expand Up @@ -206,7 +206,7 @@ flamer = "0.5"
flate2 = { version = "1.1.9", default-features = false }
foreign-types-shared = "0.3.1"
gethostname = "1.0.2"
getrandom = { version = "0.3", features = ["std"] }
getrandom = { version = "0.4", features = ["std"] }
glob = "0.3"
half = "2"
hex = "0.4.3"
Expand Down Expand Up @@ -236,7 +236,7 @@ maplit = "1.0.2"
md-5 = "0.10.1"
memchr = "2.8.0"
memmap2 = "0.9.10"
mt19937 = "<=3.2" # upgrade it once rand is upgraded
mt19937 = "3.3"
num-complex = "0.4.6"
num-integer = "0.1.46"
num-traits = "0.2"
Expand All @@ -258,8 +258,7 @@ psm = "0.1"
pymath = { version = "0.2.0", features = ["mul_add", "malachite-bigint", "complex"] }
quote = "1.0.45"
radium = "1.1.1"
rand = "0.9"
rand_core = { version = "0.9", features = ["os_rng"] }
rand = "0.10"
result-like = "0.5.0"
rustix = { version = "1.1", features = ["event"] }
rustls = { version = "0.23.39", default-features = false }
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3 changes: 3 additions & 0 deletions crates/common/Cargo.toml
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Expand Up @@ -35,5 +35,8 @@ lock_api = { workspace = true }
siphasher = { workspace = true }
num-complex = { workspace = true }

[target.'cfg(all(target_arch = "wasm32", target_os = "unknown"))'.dependencies]
getrandom = { workspace = true, features = ["wasm_js"] }

[lints]
workspace = true
2 changes: 1 addition & 1 deletion crates/literal/src/float.rs
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Expand Up @@ -303,7 +303,7 @@ pub fn to_hex(value: f64) -> String {

#[test]
fn test_to_hex() {
use rand::Rng;
use rand::RngExt;
for _ in 0..20000 {
let bytes = rand::rng().random::<u64>();
let f = f64::from_bits(bytes);
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2 changes: 1 addition & 1 deletion crates/stdlib/Cargo.toml
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Expand Up @@ -61,7 +61,7 @@ pymath = { workspace = true }
xml = { workspace = true }

# random
rand_core = { workspace = true }
rand = { workspace = true }
mt19937 = { workspace = true }

# Crypto:
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6 changes: 2 additions & 4 deletions crates/stdlib/src/random.rs
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Expand Up @@ -8,15 +8,14 @@ mod _random {
use crate::vm::{
PyObjectRef, PyPayload, PyRef, PyResult, VirtualMachine,
builtins::{PyInt, PyTupleRef},
convert::ToPyException,
function::OptionalOption,
types::{Constructor, Initializer},
};
use itertools::Itertools;
use malachite_bigint::{BigInt, BigUint, Sign};
use mt19937::MT19937;
use num_traits::{Signed, Zero};
use rand_core::{RngCore, SeedableRng};
use rand::{Rng, SeedableRng};

@coderabbitai coderabbitai Bot May 8, 2026

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⚠️ Potential issue | 🔴 Critical | ⚡ Quick win

🧩 Analysis chain

🏁 Script executed:

#!/bin/bash
# Check what rand/RngCore/Rng methods are called in random.rs
rg -n "\.next_u32\|\.next_u64\|\.fill_bytes\|\.gen\b\|\.random\b\|rand::Rng\|rand::RngCore\|rand_core" crates/stdlib/src/random.rs

Repository: RustPython/RustPython

Length of output: 47

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# Check if file exists and get the imports section
head -30 crates/stdlib/src/random.rs

Repository: RustPython/RustPython

Length of output: 851

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# Search more broadly for any 'use' statements and RNG variable usage
rg -A 5 -B 5 "use rand" crates/stdlib/src/random.rs

Repository: RustPython/RustPython

Length of output: 387

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# Look for where the RNG object is actually being used
rg -n "rng\|Rng\|RngCore" crates/stdlib/src/random.rs

Repository: RustPython/RustPython

Length of output: 47

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# Read the full file to understand RNG usage
cat -n crates/stdlib/src/random.rs | head -100

Repository: RustPython/RustPython

Length of output: 4288

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# Search for method calls on 'rng' variable without escaping
rg -n "\brng\." crates/stdlib/src/random.rs

Repository: RustPython/RustPython

Length of output: 530

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# Check what MT19937 implements - search documentation or trait bounds
rg -n "MT19937" crates/stdlib/src/random.rs | head -20

Repository: RustPython/RustPython

Length of output: 249

🏁 Script executed:

# Check if there are any compiler errors or clippy warnings in the repo
# Try to find cargo check or build output
cd crates/stdlib && cargo check 2>&1 | grep -A 5 -B 5 "random\|Rng\|error\|warning" | head -50

Repository: RustPython/RustPython

Length of output: 151

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# Search for MT19937::from_rng usage and documentation in mt19937 crate
rg -A 2 "from_rng" crates/stdlib/src/random.rs

Repository: RustPython/RustPython

Length of output: 160

🏁 Script executed:

# Check what trait MT19937 implements by searching for impl statements
rg "impl.*MT19937\|impl.*for.*MT19937" --type rust

Repository: RustPython/RustPython

Length of output: 47

🌐 Web query:

mt19937 Rust crate from_rng method parameter trait

💡 Result:

In the rand_core-based Rust ecosystem, the MT19937 generator’s “from_rng” style constructor is exposed via the rand_core::SeedableRng trait as: fn from_rng<R: RngCore>(rng: R) -> Result<Self, Error> So the parameter is a type parameter R constrained by rand_core::RngCore (an RNG producing values without error), passed by value (rng: R) and returns Result<Self, Error>. This is the generic trait signature in rand_core’s SeedableRng: [1]. Common related (infallible) variant in rand_mt: rand_mt’s Mt implements a method with signature: fn from_rng(rng: &mut R) -> Self where R: Rng +?Sized Here the parameter is &mut R, where R: rand::Rng (the infallible high-level RNG trait), and the method returns Self directly. [2] For the “mt19937” crate specifically (coolreader18/hiroshima-univ translation), its source shows implementations of rand_core::TryRng and rand_core::SeedableRng for MT19937 (but the exact from_rng signature there follows the rand_core::SeedableRng trait; the trait provides from_rng generically). [3][4] Therefore, when you ask “mt19937 Rust crate from_rng method parameter trait”, the trait bound for from_rng is R: RngCore in rand_core::SeedableRng. [1] If instead you are referring to rand_mt’s Mt::from_rng convenience API, the parameter uses &mut R where R: rand::Rng +?Sized. [2]

Citations:

🏁 Script executed:

# Check if RngCore is imported elsewhere or re-exported
rg "RngCore\|rand_core" crates/stdlib/src/random.rs

Repository: RustPython/RustPython

Length of output: 47

🏁 Script executed:

# Check if there's a re-export of RngCore in the rand crate imports
rg "use rand" crates/stdlib/src/random.rs -A 1 -B 1

Repository: RustPython/RustPython

Length of output: 185

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# Try to check Cargo.toml to see rand version and features
cat crates/stdlib/Cargo.toml | grep -A 5 -B 5 "rand"

Repository: RustPython/RustPython

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# Search for any build output or error logs
find . -name "*.log" -type f 2>/dev/null | head -5

Repository: RustPython/RustPython

Length of output: 47

Replace Rng with RngCore in the import statement.

The MT19937::from_rng() call at line 62 uses the SeedableRng::from_rng() trait method, which requires a generic parameter bound by RngCore, not Rng. The current import (use rand::{Rng, SeedableRng}) is missing RngCore and cannot satisfy the trait bound for from_rng(). While next_u32() at line 82 is a concrete method on MT19937 itself (not requiring a trait import), the trait-based from_rng() method cannot be properly used without RngCore in scope.

Proposed fix 
-    use rand::{Rng, SeedableRng};
+    use rand_core::RngCore;
+    use rand::SeedableRng;

or equivalently:

-    use rand::{Rng, SeedableRng};
+    use rand::{SeedableRng};
+    use rand_core::RngCore;
🤖 Prompt for AI Agents 
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@crates/stdlib/src/random.rs` at line 18, Import the correct trait so
SeedableRng::from_rng can use an RngCore source: replace the current import use
rand::{Rng, SeedableRng} with use rand::{RngCore, SeedableRng} (so
MT19937::from_rng / SeedableRng::from_rng has the required RngCore bound); no
changes needed for MT19937::next_u32 since that is a concrete method.

use rustpython_vm::types::DefaultConstructor;

#[pyattr]
Expand Down Expand Up @@ -60,8 +59,7 @@ mod _random {
let key = if key.is_empty() { &[0] } else { key.as_slice() };
MT19937::new_with_slice_seed(key)
}
None => MT19937::try_from_os_rng()
.map_err(|e| std::io::Error::from(e).to_pyexception(vm))?,
None => MT19937::from_rng(&mut rand::rng()),
};
Ok(())
}
Expand Down
3 changes: 2 additions & 1 deletion crates/vm/Cargo.toml
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Expand Up @@ -26,7 +26,7 @@ ast = ["ruff_python_ast", "ruff_text_size"]
codegen = ["rustpython-codegen", "ast"]
parser = ["ast"]
serde = ["dep:serde"]
wasmbind = ["rustpython-common/wasm_js", "chrono/wasmbind", "wasm-bindgen"]
wasmbind = ["rustpython-common/wasm_js", "chrono/wasmbind", "getrandom/wasm_js", "wasm-bindgen"]

[dependencies]
rustpython-compiler = { workspace = true, optional = true }
Expand Down Expand Up @@ -142,6 +142,7 @@ features = [

[target.'cfg(all(target_arch = "wasm32", target_os = "unknown"))'.dependencies]
wasm-bindgen = { workspace = true, optional = true }
getrandom = { workspace = true, features = ["wasm_js"] }

[build-dependencies]
glob = { workspace = true }
Expand Down
2 changes: 1 addition & 1 deletion crates/wasm/Cargo.toml
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Expand Up @@ -17,7 +17,7 @@ freeze-stdlib = ["rustpython-vm/freeze-stdlib", "rustpython-pylib/freeze-stdlib"
no-start-func = []

[dependencies]
rustpython-common = { workspace = true }
rustpython-common = { workspace = true, features = ["wasm_js"] }
rustpython-pylib = { workspace = true, optional = true }
rustpython-stdlib = { workspace = true, default-features = false, optional = true }
# make sure no threading! otherwise wasm build will fail
Expand Down
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