macos: add root-level .swiftlint.yml

In order to support running from both the repository root and from
within Xcode project, and to keep things generally organized, our
primary .swiftlint.yml configuration file lives under macos/.

This change introduces a root-level .swiftlint.yml which limits the file
scope to macos/ and then includes macos/.swiftlint.yml for the rest of
the directives.

This unlocks a few benefits:

- We no longer need to pass an explicit `macos` path argument in any of
  our invocations. SwiftLint will do the right thing when run either
  from the repository root or from within the macos/ directory.
- It lets us easily exclude the macos/build/ directory (and re-enable
  the 'deployment_target' rule). In the previous setup, this was more
  challenging than you'd expect due to SwiftLint's path resolution rules
  and required passing even more arguments like `--working-directory`.

The only downside is adding a new file to the repository root, but that
feels like the right trade-off given the benefits and conveniences.

.github/workflows/test.yml

@@ -23,6 +23,7 @@ jobs:
         with:
           filters: |
             macos:
+              - '.swiftlint.yml'
               - 'macos/**'
 
   required:
@@ -963,7 +964,7 @@ jobs:
           useDaemon: false # sometimes fails on short jobs
 
       - name: swiftlint check
-        run: nix develop -c swiftlint lint --strict macos
+        run: nix develop -c swiftlint lint --strict
 
   alejandra:
     if: github.repository == 'ghostty-org/ghostty'

.swiftlint.yml

@@ -0,0 +1,2 @@
+included: macos
+child_config: macos/.swiftlint.yml

AGENTS.md

@@ -8,7 +8,7 @@ A file for [guiding coding agents](https://agents.md/).
 - **Test (Zig):** `zig build test`
 - **Test filter (Zig)**: `zig build test -Dtest-filter=<test name>`
 - **Formatting (Zig)**: `zig fmt .`
-- **Formatting (Swift)**: `swiftlint lint --fix macos`
+- **Formatting (Swift)**: `swiftlint lint --fix`
 - **Formatting (other)**: `prettier -w .`
 
 ## Directory Structure

CODEOWNERS

@@ -137,6 +137,7 @@
 /dist/macos/ @ghostty-org/macos
 /pkg/apple-sdk/ @ghostty-org/macos
 /pkg/macos/ @ghostty-org/macos
+/.swiftlint.yml @ghostty-org/macos
 
 # Renderer
 /src/renderer.zig @ghostty-org/renderer

HACKING.md

@@ -194,7 +194,7 @@ are modifying Swift code, you may want to install it locally and run this from
 the repo root before you commit:
 
 ```
-swiftlint lint --fix macos
+swiftlint lint --fix
 ```
 
 Make sure your SwiftLint version matches the version in [devShell.nix](https://github.com/ghostty-org/ghostty/blob/main/nix/devShell.nix).
@@ -202,13 +202,13 @@ Make sure your SwiftLint version matches the version in [devShell.nix](https://g
 Nix users can use the following command to format with SwiftLint:
 
 ```
-nix develop -c swiftlint lint --fix macos
+nix develop -c swiftlint lint --fix
 ```
 
 To check for violations without auto-fixing:
 
 ```
-nix develop -c swiftlint lint --strict macos
+nix develop -c swiftlint lint --strict
 ```
 
 ### Updating the Zig Cache Fixed-Output Derivation Hash

macos/.swiftlint.yml

@@ -2,6 +2,9 @@
 #
 check_for_updates: false
 
+excluded:
+  - build
+
 disabled_rules:
   - cyclomatic_complexity
   - file_length
@@ -13,7 +16,6 @@ disabled_rules:
   - type_body_length
 
   # TODO
-  - deployment_target
   - for_where
   - force_cast
   - line_length

macos/Ghostty.xcodeproj/project.pbxproj

@@ -509,7 +509,7 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
-			shellScript = "[[ -z \"$GITHUB_ACTIONS\" ]] || exit 0;\n\nSWIFTLINT=\"\"\nif command -v swiftlint >/dev/null 2>&1; then\n    SWIFTLINT=\"$(command -v swiftlint)\"\nelif [[ -f \"/opt/homebrew/bin/swiftlint\" ]]; then\n    SWIFTLINT=\"/opt/homebrew/bin/swiftlint\"\nfi\n\nif [[ -n \"$SWIFTLINT\" ]]; then\n    \"$SWIFTLINT\" lint --quiet \"$SRCROOT\"\nfi\n";
+			shellScript = "[[ -z \"$GITHUB_ACTIONS\" ]] || exit 0;\n\nSWIFTLINT=\"\"\nif command -v swiftlint >/dev/null 2>&1; then\n    SWIFTLINT=\"$(command -v swiftlint)\"\nelif [[ -f \"/opt/homebrew/bin/swiftlint\" ]]; then\n    SWIFTLINT=\"/opt/homebrew/bin/swiftlint\"\nfi\n\nif [[ -n \"$SWIFTLINT\" ]]; then\n    \"$SWIFTLINT\" lint --quiet\nfi\n";
 			showEnvVarsInLog = 0;
 		};
 /* End PBXShellScriptBuildPhase section */