macos: support configuration via CLI arguments

This makes it so `zig build run` can take arguments such as
`--config-default-files=false` or any other configuration. Previously,
it only accepted commands such as `+version`.

Incidentally, this also makes it so that the app in general can now take
configuration arguments via the CLI if it is launched as a new instance
via `open`. For example:

    open -n Ghostty.app --args --config-default-files=false

This previously didn't work. This is kind of cool.

To make this work, the libghostty C API was modified so that
initialization requires the CLI args, and there is a new C API to try to
execute an action if it was set.

include/ghostty.h

@@ -778,8 +778,8 @@ typedef struct {
 //-------------------------------------------------------------------
 // Published API
 
-int ghostty_init(void);
+int ghostty_init(uintptr_t, char**);
-void ghostty_cli_main(uintptr_t, char**);
+void ghostty_cli_try_action(void);
 ghostty_info_s ghostty_info(void);
 const char* ghostty_translate(const char*);
 

macos/Ghostty-Info.plist

@@ -48,8 +48,8 @@
 	<string></string>
 	<key>LSEnvironment</key>
 	<dict>
-		<key>GHOSTTY_MAC_APP</key>
+		<key>GHOSTTY_MAC_LAUNCH_SOURCE</key>
-		<string>1</string>
+		<string>app</string>
 	</dict>
 	<key>MDItemKeywords</key>
 	<string>Terminal</string>

macos/Ghostty.xcodeproj/project.pbxproj

@@ -13,6 +13,7 @@
 		857F63812A5E64F200CA4815 /* MainMenu.xib in Resources */ = {isa = PBXBuildFile; fileRef = 857F63802A5E64F200CA4815 /* MainMenu.xib */; };
 		9351BE8E3D22937F003B3499 /* nvim in Resources */ = {isa = PBXBuildFile; fileRef = 9351BE8E2D22937F003B3499 /* nvim */; };
 		A50297352DFA0F3400B4E924 /* Double+Extension.swift in Sources */ = {isa = PBXBuildFile; fileRef = A50297342DFA0F3300B4E924 /* Double+Extension.swift */; };
+		A505D21D2E1A2FA20018808F /* FileHandle+Extension.swift in Sources */ = {isa = PBXBuildFile; fileRef = A505D21C2E1A2F9E0018808F /* FileHandle+Extension.swift */; };
 		A511940F2E050595007258CC /* CloseTerminalIntent.swift in Sources */ = {isa = PBXBuildFile; fileRef = A511940E2E050590007258CC /* CloseTerminalIntent.swift */; };
 		A51194112E05A483007258CC /* QuickTerminalIntent.swift in Sources */ = {isa = PBXBuildFile; fileRef = A51194102E05A480007258CC /* QuickTerminalIntent.swift */; };
 		A51194132E05D006007258CC /* Optional+Extension.swift in Sources */ = {isa = PBXBuildFile; fileRef = A51194122E05D003007258CC /* Optional+Extension.swift */; };
@@ -158,6 +159,7 @@
 		857F63802A5E64F200CA4815 /* MainMenu.xib */ = {isa = PBXFileReference; lastKnownFileType = file.xib; path = MainMenu.xib; sourceTree = "<group>"; };
 		9351BE8E2D22937F003B3499 /* nvim */ = {isa = PBXFileReference; lastKnownFileType = folder; name = nvim; path = "../zig-out/share/nvim"; sourceTree = "<group>"; };
 		A50297342DFA0F3300B4E924 /* Double+Extension.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Double+Extension.swift"; sourceTree = "<group>"; };
+		A505D21C2E1A2F9E0018808F /* FileHandle+Extension.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "FileHandle+Extension.swift"; sourceTree = "<group>"; };
 		A511940E2E050590007258CC /* CloseTerminalIntent.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CloseTerminalIntent.swift; sourceTree = "<group>"; };
 		A51194102E05A480007258CC /* QuickTerminalIntent.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = QuickTerminalIntent.swift; sourceTree = "<group>"; };
 		A51194122E05D003007258CC /* Optional+Extension.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Optional+Extension.swift"; sourceTree = "<group>"; };
@@ -516,6 +518,7 @@
 				A586366A2DF0A98900E04A10 /* Array+Extension.swift */,
 				A50297342DFA0F3300B4E924 /* Double+Extension.swift */,
 				A586366E2DF25D8300E04A10 /* Duration+Extension.swift */,
+				A505D21C2E1A2F9E0018808F /* FileHandle+Extension.swift */,
 				A53A29802DB44A5E00B6E02C /* KeyboardShortcut+Extension.swift */,
 				A53A297E2DB4480A00B6E02C /* EventModifiers+Extension.swift */,
 				A51194122E05D003007258CC /* Optional+Extension.swift */,
@@ -799,6 +802,7 @@
 				A5874D9D2DAD786100E83852 /* NSWindow+Extension.swift in Sources */,
 				A54D786C2CA7978E001B19B1 /* BaseTerminalController.swift in Sources */,
 				A58636732DF4813400E04A10 /* UndoManager+Extension.swift in Sources */,
+				A505D21D2E1A2FA20018808F /* FileHandle+Extension.swift in Sources */,
 				A59FB5CF2AE0DB50009128F3 /* InspectorView.swift in Sources */,
 				CFBB5FEA2D231E5000FD62EE /* QuickTerminalSpaceBehavior.swift in Sources */,
 				A54B0CE92D0CECD100CBEFF8 /* ColorizedGhosttyIconView.swift in Sources */,

macos/Sources/App/macOS/main.swift

@@ -2,13 +2,32 @@ import AppKit
 import Cocoa
 import GhosttyKit
 
-// We put the GHOSTTY_MAC_APP env var into the Info.plist to detect
+// Initialize Ghostty global state. We do this once right away because the
-// whether we launch from the app or not. A user can fake this if
+// CLI APIs require it and it lets us ensure it is done immediately for the
-// they want but they're doing so at their own detriment...
+// rest of the app.
-let process = ProcessInfo.processInfo
+if ghostty_init(UInt(CommandLine.argc), CommandLine.unsafeArgv) != GHOSTTY_SUCCESS {
-if ((process.environment["GHOSTTY_MAC_APP"] ?? "") == "") {
+    Ghostty.logger.critical("ghostty_init failed")
-    ghostty_cli_main(UInt(CommandLine.argc), CommandLine.unsafeArgv)
+    
+    // We also write to stderr if this is executed from the CLI or zig run
+    switch Ghostty.launchSource {
+    case .cli, .zig_run:
+        let stderrHandle = FileHandle.standardError
+        stderrHandle.write(
+            "Ghostty failed to initialize! If you're executing Ghostty from the command line\n" +
+            "then this is usually because an invalid action or multiple actions were specified.\n" +
+            "Actions start with the `+` character.\n\n" +
+            "View all available actions by running `ghostty +help`.\n")
         exit(1)
+        
+    case .app:
+        // For the app we exit immediately. We should handle this case more
+        // gracefully in the future.
+        exit(1)
+    }
 }
 
+// This will run the CLI action and exit if one was specified. A CLI
+// action is a command starting with a `+`, such as `ghostty +boo`.
+ghostty_cli_try_action();
+
 _ = NSApplicationMain(CommandLine.argc, CommandLine.unsafeArgv)

macos/Sources/Ghostty/Ghostty.App.swift

@@ -45,12 +45,6 @@ extension Ghostty {
         }
 
         init() {
-            // Initialize ghostty global state. This happens once per process.
-            if ghostty_init() != GHOSTTY_SUCCESS {
-                logger.critical("ghostty_init failed, weird things may happen")
-                readiness = .error
-            }
-
             // Initialize the global configuration.
             self.config = Config()
             if self.config.config == nil {

macos/Sources/Ghostty/Package.swift

@@ -61,9 +61,12 @@ extension Ghostty {
     /// its up to the env var being set in the correct circumstance.
     static var launchSource: LaunchSource {
         guard let envValue = ProcessInfo.processInfo.environment["GHOSTTY_MAC_LAUNCH_SOURCE"] else {
-            return .app
+            // We default to the CLI because the app bundle always sets the
+            // source. If its unset we assume we're in a CLI environment.
+            return .cli
         }
         
+        // If the env var is set but its unknown then we default back to the app.
         return LaunchSource(rawValue: envValue) ?? .app
     }
 }

macos/Sources/Helpers/Extensions/FileHandle+Extension.swift

@@ -0,0 +1,9 @@
+import Foundation
+
+extension FileHandle: @retroactive TextOutputStream {
+    /// Write a string to a filehandle.
+    public func write(_ string: String) {
+        let data = Data(string.utf8)
+        self.write(data)
+    }
+}

src/apprt/embedded.zig

@@ -884,7 +884,7 @@ pub const Surface = struct {
             }
 
             // Remove this so that running `ghostty` within Ghostty works.
-            env.remove("GHOSTTY_MAC_APP");
+            env.remove("GHOSTTY_MAC_LAUNCH_SOURCE");
 
             // If we were launched from the desktop then we want to
             // remove the LANGUAGE env var so that we don't inherit

src/build/GhosttyXcodebuild.zig

@@ -122,10 +122,6 @@ pub fn init(
 
         if (b.args) |args| {
             open.addArgs(args);
-        } else {
-            // This tricks the app into thinking it's running from the
-            // app bundle so we don't execute our CLI mode.
-            open.setEnvironmentVariable("GHOSTTY_MAC_APP", "1");
         }
 
         break :open open;

src/main_c.zig

@@ -46,17 +46,11 @@ const Info = extern struct {
     };
 };
 
-/// Initialize ghostty global state. It is possible to have more than
+/// Initialize ghostty global state.
-/// one global state but it has zero practical benefit.
+export fn ghostty_init(argc: usize, argv: [*][*:0]u8) c_int {
-export fn ghostty_init() c_int {
     assert(builtin.link_libc);
 
-    // Since in the lib we don't go through start.zig, we need
+    std.os.argv = argv[0..argc];
-    // to populate argv so that inspecting std.os.argv doesn't
-    // touch uninitialized memory.
-    var argv: [0][*:0]u8 = .{};
-    std.os.argv = &argv;
-
     state.init() catch |err| {
         std.log.err("failed to initialize ghostty error={}", .{err});
         return 1;
@@ -65,15 +59,17 @@ export fn ghostty_init() c_int {
     return 0;
 }
 
-/// This is the entrypoint for the CLI version of Ghostty. This
+/// Runs an action if it is specified. If there is no action this returns
-/// is mutually exclusive to ghostty_init. Do NOT run ghostty_init
+/// false. If there is an action then this doesn't return.
-/// if you are going to run this. This will not return.
+export fn ghostty_cli_try_action() void {
-export fn ghostty_cli_main(argc: usize, argv: [*][*:0]u8) noreturn {
+    const action = state.action orelse return;
-    std.os.argv = argv[0..argc];
+    std.log.info("executing CLI action={}", .{action});
-    main.main() catch |err| {
+    posix.exit(action.run(state.alloc) catch |err| {
-        std.log.err("failed to run ghostty error={}", .{err});
+        std.log.err("CLI action failed error={}", .{err});
         posix.exit(1);
-    };
+    });
+
+    posix.exit(0);
 }
 
 /// Return metadata about Ghostty, such as version, build mode, etc.

src/os/desktop.zig

@@ -24,8 +24,15 @@ pub fn launchedFromDesktop() bool {
             // This special case is so that if we launch the app via the
             // app bundle (i.e. via open) then we still treat it as if it
             // was launched from the desktop.
-            if (build_config.artifact == .lib and
+            if (build_config.artifact == .lib) lib: {
-                posix.getenv("GHOSTTY_MAC_APP") != null) break :macos true;
+                const env = "GHOSTTY_MAC_LAUNCH_SOURCE";
+                const source = posix.getenv(env) orelse break :lib;
+
+                // Source can be "app", "cli", or "zig_run". We assume
+                // its the desktop only if its "app". We may want to do
+                // "zig_run" but at the moment there's no reason.
+                if (std.mem.eql(u8, source, "app")) break :macos true;
+            }
 
             break :macos c.getppid() == 1;
         },