Remove the usage of the mozilla rust overlay

By switching to the tools bundled within nixpkgs we can provide a much
more "pure" development environment that doesn't randomly change over
time.

Previously we would be using the latest and greatest version of the
formatting and linting tools while our development environment only
offered whatever was in the (old) nixpkgs pin. Nowadays we have all the
tools we need in nixpkgs and can thus use those instead. By following
nixpkgs more closely we can make sure to make use of those tools in this
project as well. Hopefully removing the "yearly churn" of doing big
migrations.

For the meantime I allowed the upper case acronyms check (and a few
other minor lints) in the clippy configuration. This will allow a
smoother transition towards the newer clippy code that is decoupled from
the actual linting changes.

.github/workflows/ci.yml

@@ -6,17 +6,6 @@ on:
   pull_request:
 
 jobs:
-  pedantry:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v2
-      - name: Install Nix
-        uses: cachix/install-nix-action@v12
-        with:
-          nix_path: nixpkgs=channel:nixos-unstable
-      - name: Cargo Pedantry
-        run: nix-shell --run checkPhase -A mozilla-rust-overlay
-  
   checkPhase:
     runs-on: ubuntu-latest
     steps:
@@ -30,7 +19,7 @@ jobs:
           git config --global user.email "ofborg@example.com"
           git config --global user.name "ofborg"
       - name: checkPhase
-        run: nix-shell --run checkPhase
+        run: nix-shell --pure --run checkPhase
 
   nix-build:
     runs-on: ubuntu-latest

README.md

@@ -209,8 +209,7 @@ To test whether or not Continuous Integration will pass with your changes, you
 can run the following commands from the root of your checkout:
 
 ```shell
-$ nix-shell --run checkPhase -A mozilla-rust-overlay # checks rustfmt and clippy
-$ nix-shell --run checkPhase # runs the test suite
+$ nix-shell --pure --run checkPhase # checks rustfmt, clippy & runs the test suite
 $ nix-build -A ofborg.rs # build ofborg
 ```
 

shell.nix

@@ -1,7 +1,6 @@
 { pkgs ? import ./nix {
   overlays = [
     (import ./nix/overlay.nix)
-    (import (builtins.fetchTarball https://github.com/mozilla/nixpkgs-mozilla/archive/master.tar.gz))
   ];
 } }:
 
@@ -24,65 +23,49 @@ let
     # HISTFILE = "${src}/.bash_hist";
   };
 
-  mozilla-rust-overlay = stdenv.mkDerivation {
-    name = "mozilla-rust-overlay";
-    buildInputs = with pkgs; [
-      latest.rustChannels.stable.rust
-      git
+  rustEnv = stdenv.mkDerivation {
+    name = "gh-event-forwarder";
+    nativeBuildInputs = with pkgs; [
+      nix # so in --pure mode we actually find the "correct" nix
+      bash
+      nix-prefetch-git
+      rustPackages.cargo
+      rustPackages.clippy
+      rustPackages.rustfmt
       pkg-config
+      git
+    ];
+    buildInputs = with pkgs; [
       openssl
     ]
       ++ lib.optional stdenv.isDarwin pkgs.darwin.Security;
 
     postHook = ''
       checkPhase() (
-        cd "${builtins.toString ./.}/ofborg"
+          cd "${builtins.toString ./.}/ofborg"
+          set -x
+          cargo fmt
+          git diff --exit-code
+          cargofmtexit=$?
   
-        set -x
+          cargo clippy
+          cargoclippyexit=$?
   
-        cargo fmt
-        git diff --exit-code
-        cargofmtexit=$?
 
-        cargo clippy
-        cargoclippyexit=$?
+          cargo build && cargo test
+          cargotestexit=$?
 
-        sum=$((cargofmtexit + cargoclippyexit))
-        exit $sum
+          sum=$((cargofmtexit + cargoclippyexit + cargotestexit))
+          exit $sum
       )
     '';
 
-    RUSTFLAGS = "-D warnings";
-    RUST_BACKTRACE = "1";
-    NIX_PATH = "nixpkgs=${pkgs.path}";
-  };
-
-  rustEnv = stdenv.mkDerivation {
-    name = "gh-event-forwarder";
-    buildInputs = with pkgs; [
-      bash
-      nix-prefetch-git
-      latest.rustChannels.stable.rust
-      #rustfmt
-      openssl
-      pkg-config
-      git
-    ]
-      ++ lib.optional stdenv.isDarwin pkgs.darwin.Security;
-
-    postHook = ''
-      checkPhase() {
-          ( cd "${builtins.toString ./.}/ofborg" && cargo build && cargo test)
-      }
-    '';
-
     HISTFILE = "${toString ./.}/.bash_hist";
     RUSTFLAGS = "-D warnings";
     RUST_BACKTRACE = "1";
     RUST_LOG = "ofborg=debug";
     NIX_PATH = "nixpkgs=${pkgs.path}";
     passthru.phpEnv = phpEnv;
-    passthru.mozilla-rust-overlay = mozilla-rust-overlay;
   };
 
 in rustEnv