Switch to Blake3 hashing

Summary: This is what Glean does.

Reviewed By: kinto0

Differential Revision: D72962139

fbshipit-source-id: 9efd231d428c8617fb8ff65a5773088680540ae0

Author: ndmitchell

pyrefly/Cargo.toml

@@ -21,6 +21,7 @@ anyhow = "1.0.95"
 append-only-vec = "0.1.2"
 argfile = "0.1.6"
 async-trait = "0.1.86"
+blake3 = { version = "=1.5.2", features = ["mmap", "rayon", "traits-preview"] }
 clap = { version = "4.5.30", features = ["derive", "env", "string", "unicode", "wrap_help"] }
 const-str = "0.4.3"
 convert_case = "0.6"

pyrefly/lib/report/glean/convert.rs

@@ -5,9 +5,6 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-use std::hash::DefaultHasher;
-use std::hash::Hasher;
-
 use ruff_python_ast::ModModule;
 use serde::Serialize;
 use serde_json::Value;
@@ -22,10 +19,8 @@ fn json(x: impl Serialize) -> Value {
 }
 
 fn hash(x: &[u8]) -> String {
-    // TODO: Use whatever hash algorithm Glean uses
-    let mut hasher = DefaultHasher::new();
-    hasher.write(x);
-    hasher.finish().to_string()
+    // Glean uses blake3
+    blake3::hash(x).to_string()
 }
 
 impl Glean {