Shrink Dist from 496 bytes to 240 by boxing File

`Dist` was standing out when profiling stack sizes with top-type-sizes. Here, we trade an allocation per `Dist` for a more reasonable stack size.

Cargo.toml

@@ -74,6 +74,7 @@ seahash = { version = "4.1.0" }
 serde = { version = "1.0.194" }
 serde_json = { version = "1.0.111" }
 sha2 = { version = "0.10.8" }
+static_assertions = { version = "1.1.0" }
 tar = { version = "0.4.40" }
 target-lexicon = { version = "0.12.13" }
 tempfile = { version = "3.9.0" }

crates/distribution-types/Cargo.toml

@@ -32,5 +32,6 @@ rustc-hash = { workspace = true }
 serde = { workspace = true, features = ["derive"] }
 serde_json = { workspace = true }
 sha2 = { workspace = true }
+static_assertions = { workspace = true }
 thiserror = { workspace = true }
 url = { workspace = true }

crates/distribution-types/src/lib.rs

@@ -37,6 +37,7 @@ use std::path::{Path, PathBuf};
 use std::str::FromStr;
 
 use anyhow::Result;
+use static_assertions::assert_eq_size;
 use url::Url;
 
 use distribution_filename::{DistFilename, SourceDistFilename, WheelFilename};
@@ -147,7 +148,7 @@ pub enum SourceDist {
 #[derive(Debug, Clone)]
 pub struct RegistryBuiltDist {
     pub filename: WheelFilename,
-    pub file: File,
+    pub file: Box<File>,
     pub index: IndexUrl,
 }
 
@@ -172,7 +173,7 @@ pub struct PathBuiltDist {
 #[derive(Debug, Clone)]
 pub struct RegistrySourceDist {
     pub filename: SourceDistFilename,
-    pub file: File,
+    pub file: Box<File>,
     pub index: IndexUrl,
 }
 
@@ -201,21 +202,25 @@ pub struct PathSourceDist {
     pub editable: bool,
 }
 
+assert_eq_size!(Dist, [u8; 240]);
+assert_eq_size!(BuiltDist, [u8; 240]);
+assert_eq_size!(SourceDist, [u8; 168]);
+
 impl Dist {
     /// Create a [`Dist`] for a registry-based distribution.
     pub fn from_registry(filename: DistFilename, file: File, index: IndexUrl) -> Self {
         match filename {
             DistFilename::WheelFilename(filename) => {
                 Self::Built(BuiltDist::Registry(RegistryBuiltDist {
                     filename,
-                    file,
+                    file: Box::new(file),
                     index,
                 }))
             }
             DistFilename::SourceDistFilename(filename) => {
                 Self::Source(SourceDist::Registry(RegistrySourceDist {
                     filename,
-                    file,
+                    file: Box::new(file),
                     index,
                 }))
             }

crates/puffin-client/src/flat_index.rs

@@ -221,7 +221,7 @@ impl FlatIndex {
 
                 let dist = Dist::Built(BuiltDist::Registry(RegistryBuiltDist {
                     filename,
-                    file,
+                    file: Box::new(file),
                     index,
                 }));
                 match distributions.0.entry(version) {
@@ -238,7 +238,7 @@ impl FlatIndex {
             DistFilename::SourceDistFilename(filename) => {
                 let dist = Dist::Source(SourceDist::Registry(RegistrySourceDist {
                     filename: filename.clone(),
-                    file,
+                    file: Box::new(file),
                     index,
                 }));
                 match distributions.0.entry(filename.version.clone()) {