RFC: Migrate all Rust packages to importCargoLock

maintainers/scripts/convert-to-import-cargo-lock.sh

@@ -0,0 +1,4 @@
+#!/usr/bin/env nix-shell
+#!nix-shell -I nixpkgs=. -i bash -p "import ./maintainers/scripts/convert-to-import-cargo-lock" nix-prefetch-git
+
+convert-to-import-cargo-lock "$@"

maintainers/scripts/convert-to-import-cargo-lock/.gitignore

@@ -0,0 +1 @@
+/target

maintainers/scripts/convert-to-import-cargo-lock/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "convert-to-import-cargo-lock"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+anyhow = { version = "1.0.69" }
+basic-toml = "0.1.1"
+serde = { version = "1.0.152", features = ["derive"] }
+serde_json = "1.0.93"

maintainers/scripts/convert-to-import-cargo-lock/default.nix

@@ -0,0 +1,16 @@
+with import ../../../. { };
+
+rustPlatform.buildRustPackage {
+  name = "convert-to-import-cargo-lock";
+
+  src = lib.cleanSourceWith {
+    src = ./.;
+    filter = name: type:
+      let
+        name' = builtins.baseNameOf name;
+      in
+      name' != "default.nix" && name' != "target";
+  };
+
+  cargoLock.lockFile = ./Cargo.lock;
+}

maintainers/scripts/convert-to-import-cargo-lock/shell.nix

@@ -0,0 +1,5 @@
+with import ../../../. { };
+
+mkShell {
+  packages = [ rustc cargo clippy rustfmt ] ++ lib.optional stdenv.isDarwin libiconv;
+}

maintainers/scripts/convert-to-import-cargo-lock/src/main.rs

@@ -0,0 +1,246 @@
+#![warn(clippy::pedantic)]
+#![allow(clippy::too_many_lines)]
+
+use anyhow::anyhow;
+use serde::Deserialize;
+use std::{collections::HashMap, env, fs, path::PathBuf, process::Command};
+
+#[derive(Deserialize)]
+struct CargoLock<'a> {
+    #[serde(rename = "package", borrow)]
+    packages: Vec<Package<'a>>,
+    metadata: Option<HashMap<&'a str, &'a str>>,
+}
+
+#[derive(Deserialize)]
+struct Package<'a> {
+    name: &'a str,
+    version: &'a str,
+    source: Option<&'a str>,
+    checksum: Option<&'a str>,
+}
+
+#[derive(Deserialize)]
+struct PrefetchOutput {
+    sha256: String,
+}
+
+fn main() -> anyhow::Result<()> {
+    let mut hashes = HashMap::new();
+
+    let attr_count = env::args().len() - 1;
+
+    for (i, attr) in env::args().skip(1).enumerate() {
+        println!("converting {attr} ({}/{attr_count})", i + 1);
+
+        convert(&attr, &mut hashes)?;
+    }
+
+    Ok(())
+}
+
+fn convert(attr: &str, hashes: &mut HashMap<String, String>) -> anyhow::Result<()> {
+    let package_path = nix_eval(format!("{attr}.meta.position"))?
+        .and_then(|p| p.split_once(':').map(|(f, _)| PathBuf::from(f)));
+
+    if package_path.is_none() {
+        eprintln!("can't automatically convert {attr}: doesn't exist");
+        return Ok(());
+    }
+
+    let package_path = package_path.unwrap();
+
+    if package_path.with_file_name("Cargo.lock").exists() {
+        eprintln!("skipping {attr}: already has a vendored Cargo.lock");
+        return Ok(());
+    }
+
+    let mut src = PathBuf::from(
+        String::from_utf8(
+            Command::new("nix-build")
+                .arg("-A")
+                .arg(format!("{attr}.src"))
+                .output()?
+                .stdout,
+        )?
+        .trim(),
+    );
+
+    if !src.exists() {
+        eprintln!("can't automatically convert {attr}: src doesn't exist (bad attr?)");
+        return Ok(());
+    } else if !src.metadata()?.is_dir() {
+        eprintln!("can't automatically convert {attr}: src isn't a directory");
+        return Ok(());
+    }
+
+    if let Some(mut source_root) = nix_eval(format!("{attr}.sourceRoot"))?.map(PathBuf::from) {
+        source_root = source_root.components().skip(1).collect();
+        src.push(source_root);
+    }
+
+    let cargo_lock_path = src.join("Cargo.lock");
+
+    if !cargo_lock_path.exists() {
+        eprintln!("can't automatically convert {attr}: src doesn't contain Cargo.lock");
+        return Ok(());
+    }
+
+    let cargo_lock_content = fs::read_to_string(cargo_lock_path)?;
+
+    let cargo_lock: CargoLock = basic_toml::from_str(&cargo_lock_content)?;
+
+    let mut git_dependencies = Vec::new();
+
+    for package in cargo_lock.packages.iter().filter(|p| {
+        p.source.is_some()
+            && p.checksum
+                .or_else(|| {
+                    cargo_lock
+                        .metadata
+                        .as_ref()?
+                        .get(
+                            format!("checksum {} {} ({})", p.name, p.version, p.source.unwrap())
+                                .as_str(),
+                        )
+                        .copied()
+                })
+                .is_none()
+    }) {
+        let (typ, original_url) = package
+            .source
+            .unwrap()
+            .split_once('+')
+            .expect("dependency should have well-formed source url");
+
+        if let Some(hash) = hashes.get(original_url) {
+            git_dependencies.push((
+                format!("{}-{}", package.name, package.version),
+                hash.clone(),
+            ));
+
+            continue;
+        }
+
+        assert_eq!(
+            typ, "git",
+            "packages without checksums should be git dependencies"
+        );
+
+        let (mut url, rev) = original_url
+            .split_once('#')
+            .expect("git dependency should have commit");
+
+        // TODO: improve
+        if let Some((u, _)) = url.split_once('?') {
+            url = u;
+        }
+
+        let prefetch_output: PrefetchOutput = serde_json::from_slice(
+            &Command::new("nix-prefetch-git")
+                .args(["--url", url, "--rev", rev, "--quiet"])
+                .output()?
+                .stdout,
+        )?;
+
+        let output_hash = String::from_utf8(
+            Command::new("nix")
+                .args([
+                    "--extra-experimental-features",
+                    "nix-command",
+                    "hash",
+                    "to-sri",
+                    "--type",
+                    "sha256",
+                    &prefetch_output.sha256,
+                ])
+                .output()?
+                .stdout,
+        )?;
+
+        let hash = output_hash.trim().to_string();
+
+        git_dependencies.push((
+            format!("{}-{}", package.name, package.version),
+            output_hash.trim().to_string().clone(),
+        ));
+
+        hashes.insert(original_url.to_string(), hash);
+    }
+
+    fs::write(
+        package_path.with_file_name("Cargo.lock"),
+        cargo_lock_content,
+    )?;
+
+    let mut package_lines: Vec<_> = fs::read_to_string(&package_path)?
+        .lines()
+        .map(String::from)
+        .collect();
+
+    let (cargo_deps_line_index, cargo_deps_line) = package_lines
+        .iter_mut()
+        .enumerate()
+        .find(|(_, l)| {
+            l.trim_start().starts_with("cargoHash") || l.trim_start().starts_with("cargoSha256")
+        })
+        .expect("package should contain cargoHash/cargoSha256");
+
+    let spaces = " ".repeat(cargo_deps_line.len() - cargo_deps_line.trim_start().len());
+
+    if git_dependencies.is_empty() {
+        *cargo_deps_line = format!("{spaces}cargoLock.lockFile = ./Cargo.lock;");
+    } else {
+        *cargo_deps_line = format!("{spaces}cargoLock = {{");
+
+        let mut index_iter = cargo_deps_line_index + 1..;
+
+        package_lines.insert(
+            index_iter.next().unwrap(),
+            format!("{spaces}  lockFile = ./Cargo.lock;"),
+        );
+
+        package_lines.insert(
+            index_iter.next().unwrap(),
+            format!("{spaces}  outputHashes = {{"),
+        );
+
+        for ((dep, hash), index) in git_dependencies.drain(..).zip(&mut index_iter) {
+            package_lines.insert(index, format!("{spaces}    {dep:?} = {hash:?};"));
+        }
+
+        package_lines.insert(index_iter.next().unwrap(), format!("{spaces}  }};"));
+        package_lines.insert(index_iter.next().unwrap(), format!("{spaces}}};"));
+    }
+
+    if package_lines.last().map(String::as_str) != Some("") {
+        package_lines.push(String::new());
+    }
+
+    fs::write(package_path, package_lines.join("\n"))?;
+
+    Ok(())
+}
+
+fn nix_eval(attr: impl AsRef<str>) -> anyhow::Result<Option<String>> {
+    let output = String::from_utf8(
+        Command::new("nix-instantiate")
+            .args(["--eval", "-A", attr.as_ref()])
+            .output()?
+            .stdout,
+    )?;
+
+    let trimmed = output.trim();
+
+    if trimmed.is_empty() || trimmed == "null" {
+        Ok(None)
+    } else {
+        Ok(Some(
+            trimmed
+                .strip_prefix('"')
+                .and_then(|p| p.strip_suffix('"'))
+                .ok_or_else(|| anyhow!("couldn't parse nix-instantiate output: {output:?}"))?
+                .to_string(),
+        ))
+    }
+}