build(toolchain),ci: switch to rust 1.82-beta for now

`precise_capturing` has no workaround but we need it in tests. The main
crate should still compile under stable rustc, which is enforced by CI.

.github/workflows/ci.yaml

@@ -20,10 +20,10 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
-      - name: Install Rust stable
+      - name: Install Rust beta
         run: |
-          rustup update --no-self-update stable
-          rustup default stable
+          rustup update --no-self-update beta
+          rustup default beta
 
       - name: Cache dependencies
         uses: Swatinem/rust-cache@v2
@@ -40,7 +40,7 @@ jobs:
   test:
     strategy:
       matrix:
-        rust: [stable]
+        rust: [stable, beta]
     name: Test ${{ matrix.rust }}
     runs-on: ubuntu-latest
     timeout-minutes: 15
@@ -48,11 +48,18 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
+      - name: Disable high-priority rust-toolchain.toml
+        run: rm rust-toolchain.toml
+
       - name: Install Rust ${{ matrix.rust }}
         run: |
           rustup update --no-self-update ${{ matrix.rust }}
           rustup default ${{ matrix.rust }}
 
+      - name: Disable integration tests on stable rustc
+        if: matrix.rust == 'stable'
+        run: mv ./blahd/tests{,-disabled}
+
       - name: Cache Dependencies
         uses: Swatinem/rust-cache@v2
 

Cargo.toml

@@ -8,7 +8,7 @@ members = [
 default-members = ["blahd"]
 
 [workspace.lints.clippy]
-allow_attributes = "warn"
+allow_attributes_without_reason = "warn"
 dbg_macro = "warn"
 print_stderr = "warn"
 print_stdout = "warn"

blahd/src/lib.rs

@@ -119,6 +119,10 @@ type RE<T> = R<T, ApiError>;
 async fn handle_ws(State(st): ArcState, ws: WebSocketUpgrade) -> Response {
     ws.on_upgrade(move |mut socket| async move {
         match event::handle_ws(st, &mut socket).await {
+            #[allow(
+                unreachable_patterns,
+                reason = "compatibility before min_exhaustive_patterns"
+            )]
             Ok(never) => match never {},
             Err(err) if err.is::<event::StreamEnded>() => {}
             Err(err) => {

blahd/tests/basic.rs

@@ -1,7 +1,7 @@
 #![expect(clippy::unwrap_used, reason = "FIXME: random false positive")]
 #![expect(clippy::toplevel_ref_arg, reason = "easy to use for fixtures")]
 use std::fmt;
-use std::future::IntoFuture;
+use std::future::{Future, IntoFuture};
 use std::sync::{Arc, LazyLock};
 
 use anyhow::Result;
@@ -144,7 +144,7 @@ async fn smoke(server: Server) {
     assert_eq!(got, exp);
 }
 
-fn sign<T: Serialize>(key: &SigningKey, rng: &mut impl RngCore, payload: T) -> WithSig<T> {
+fn sign<T: Serialize>(key: &SigningKey, rng: &mut dyn RngCore, payload: T) -> WithSig<T> {
     WithSig::sign(key, get_timestamp(), rng, payload).unwrap()
 }
 
@@ -152,13 +152,13 @@ fn auth(key: &SigningKey, rng: &mut impl RngCore) -> String {
     serde_json::to_string(&sign(key, rng, AuthPayload {})).unwrap()
 }
 
-async fn create_room(
-    server: &Server,
+fn create_room<'s>(
+    server: &'s Server,
     key: &SigningKey,
-    rng: &mut impl RngCore,
+    rng: &mut dyn RngCore,
     attrs: RoomAttrs,
-    title: impl fmt::Display,
-) -> Result<Id> {
+    title: &str,
+) -> impl Future<Output = Result<Id>> + use<'s> {
     let req = sign(
         key,
         rng,
@@ -171,10 +171,12 @@ async fn create_room(
             title: title.to_string(),
         },
     );
+    async move {
         Ok(server
             .request(Method::POST, "/room/create", None, Some(&req))
             .await?
             .unwrap())
+    }
 }
 
 #[rstest]
@@ -202,13 +204,7 @@ async fn room_create_get(server: Server, ref mut rng: impl RngCore, #[case] publ
     room_meta.rid = rid;
 
     // Bob has no permission.
-    create_room(
-        &server,
-        &BOB_PRIV,
-        rng,
-        room_meta.attrs,
-        room_meta.title.clone(),
-    )
+    create_room(&server, &BOB_PRIV, rng, room_meta.attrs, &room_meta.title)
         .await
         .expect_api_err(StatusCode::FORBIDDEN, "permission_denied");
 

flake.lock

@@ -39,7 +39,28 @@
     "root": {
       "inputs": {
         "naersk": "naersk",
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "rust-overlay": "rust-overlay"
+      }
+    },
+    "rust-overlay": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1725935143,
+        "narHash": "sha256-mVtTVQMlXkydSXVwFClE0ckxHrOQ9nb2DrCjNwW5pUE=",
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "rev": "c3c175c74cd0e8c2c40a0e22bc6e3005c4d28d64",
+        "type": "github"
+      },
+      "original": {
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "type": "github"
       }
     }
   },

flake.nix

@@ -7,6 +7,10 @@ rec {
       url = "github:nix-community/naersk";
       inputs.nixpkgs.follows = "nixpkgs";
     };
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
   };
 
   outputs =
@@ -14,6 +18,7 @@ rec {
       self,
       nixpkgs,
       naersk,
+      rust-overlay,
     }:
     let
       inherit (nixpkgs) lib;
@@ -26,7 +31,13 @@ rec {
         system:
         let
           pkgs = nixpkgs.legacyPackages.${system};
-          naersk' = pkgs.callPackage naersk { };
+          rustBin = rust-overlay.lib.mkRustBin { } pkgs;
+          toolchain = rustBin.fromRustupToolchainFile ./rust-toolchain.toml;
+          naersk' = pkgs.callPackage naersk {
+            cargo = toolchain;
+            rustc = toolchain;
+          };
+
           mkPkg =
             {
               pkg-config,
@@ -75,6 +86,21 @@ rec {
         }
       );
 
+      devShells = eachSystem (
+        system:
+        let
+          pkgs = nixpkgs.legacyPackages.${system};
+        in
+        {
+          default = pkgs.mkShell {
+            inputsFrom = [ self.packages.${system}.default ];
+            nativeBuildInputs = [ pkgs.buildPackages.sqlite-interactive ];
+
+            env.RUST_LOG = "blahd=debug,blahctl=debug";
+          };
+        }
+      );
+
       nixosModules = rec {
         default = blahd;
         blahd = import ./contrib/module.nix {

rust-toolchain.toml

@@ -0,0 +1,7 @@
+# WAIT: Rust 1.82 release on 2024-10-17
+# Used features:
+# - min_exhaustive_patterns: https://github.com/rust-lang/rust/issues/119612
+# - precise_capturing: https://github.com/rust-lang/rust/issues/123432
+[toolchain]
+channel = "beta-2024-09-10" # 1.82.0-beta.3
+profile = "default"

shell.nix

@@ -1,7 +0,0 @@
-with import <nixpkgs> { };
-mkShell {
-  nativeBuildInputs = [ pkg-config sqlite-interactive ];
-  buildInputs = [ openssl.dev sqlite.dev ];
-
-  env.RUST_LOG = "blahd=debug,blahctl=debug";
-}