feat: restore original toolchain if installed

BD103 · BD103 · commit 58400451ad64 · 2025-04-24T09:15:41.000-04:00
diff --git a/bevy_lint/action.yml b/bevy_lint/action.yml
@@ -6,12 +6,23 @@ description: |
   This action currently uses Rustup to install the required toolchain components, and it uses
   `cargo install` to install the linter itself. The linter will be installed to `~/.cargo/bin` and
   will be available through the `PATH` by default.
-
-  Note that this currently will override the default Rustup toolchain to nightly. You can fix this
-  by calling `rustup default` after this action is run.
 runs:
   using: composite
   steps:
+    # `dtolnay/rust-toolchain` overrides the default toolchain. We track what the original default
+    # is and restore it afterwards.
+    - name: Save original toolchain
+      id: original-toolchain
+      shell: bash
+      # This may fail if Rustup is not installed, in which case we continue anyways.
+      continue-on-error: true
+      run: |
+        # This prints what toolchain is installed, such as "stable-aarch64-apple-darwin (default)".
+        DEFAULT="$(rustup default)"
+
+        # We use `%` to strip "(default)" from the end of the output.
+        echo "original-toolchain=${DEFAULT%(default)}" >> "${GITHUB_OUTPUT}"
+
     - name: Install Rust toolchain and components
       uses: dtolnay/rust-toolchain@master
       with:
@@ -29,3 +40,12 @@ runs:
           --branch main \
           --locked \
           bevy_lint
+
+    - name: Restore original toolchain
+      # If Rustup wasn't installed, causing `original-toolchain` to fail, we don't need to restore
+      # the original toolchain since there wasn't one in the first place!
+      if: ${{ steps.original-toolchain.outcome != 'failure' }}
+      shell: bash
+      env:
+        ORIGINAL_TOOLCHAIN: ${{ steps.original-toolchain.outputs.original-toolchain }}
+      run: rustup default "${ORIGINAL_TOOLCHAIN}"
