Change default log level to warning.

Ghostty's default log level is now "warning" unless one of the following
conditions is met...
* A "+action" is being run in which case it's "error".
* There's no app_runtime (lib mode) in which case it's "error".
* The GHOSTTY_LOG environment variable isn't empty in which case it's "info".
* Ghostty was started from a desktop/launcher icon in which case it's "info".
* A debug build is being run in which case it's "debug".

The conditons are evaluated from top to bottom and the last one met wins.

src/global.zig

@@ -26,19 +26,13 @@ pub const GlobalState = struct {
     gpa: ?GPA,
     alloc: std.mem.Allocator,
     action: ?cli.Action,
-    logging: Logging,
+    log_level: std.log.Level,
     rlimits: ResourceLimits = .{},
 
     /// The app resources directory, equivalent to zig-out/share when we build
     /// from source. This is null if we can't detect it.
     resources_dir: ?[]const u8,
 
-    /// Where logging should go
-    pub const Logging = union(enum) {
-        disabled: void,
-        stderr: void,
-    };
-
     /// Initialize the global state.
     pub fn init(self: *GlobalState) !void {
         // const start = try std.time.Instant.now();
@@ -56,7 +50,7 @@ pub const GlobalState = struct {
             .gpa = null,
             .alloc = undefined,
             .action = null,
-            .logging = .{ .stderr = {} },
+            .log_level = .warn,
             .rlimits = .{},
             .resources_dir = null,
         };
@@ -92,11 +86,11 @@ pub const GlobalState = struct {
         // If we have an action executing, we disable logging by default
         // since we write to stderr we don't want logs messing up our
         // output.
-        if (self.action != null) self.logging = .{ .disabled = {} };
+        if (self.action != null) self.log_level = .err;
 
         // For lib mode we always disable stderr logging by default.
         if (comptime build_config.app_runtime == .none) {
-            self.logging = .{ .disabled = {} };
+            self.log_level = .err;
         }
 
         // I don't love the env var name but I don't have it in my heart
@@ -107,10 +101,18 @@ pub const GlobalState = struct {
         if ((try internal_os.getenv(self.alloc, "GHOSTTY_LOG"))) |v| {
             defer v.deinit(self.alloc);
             if (v.value.len > 0) {
-                self.logging = .{ .stderr = {} };
+                self.log_level = .info;
             }
         }
 
+        if (internal_os.launchedFromDesktop()) {
+            self.log_level = .info;
+        }
+
+        if (builtin.mode == .Debug) {
+            self.log_level = .debug;
+        }
+
         // Setup our signal handlers before logging
         initSignals();
 

src/main_ghostty.zig

@@ -119,6 +119,12 @@ fn logFn(
     comptime format: []const u8,
     args: anytype,
 ) void {
+
+    // If we're not logging messages at this level, we can just stop now.
+    if (@intFromEnum(level) > @intFromEnum(state.log_level)) {
+        return;
+    }
+
     // Stuff we can do before the lock
     const level_txt = comptime level.asText();
     const prefix = if (scope == .default) ": " else "(" ++ @tagName(scope) ++ "): ";
@@ -147,15 +153,9 @@ fn logFn(
         logger.log(std.heap.c_allocator, mac_level, format, args);
     }
 
-    switch (state.logging) {
-        .disabled => {},
-
-        .stderr => {
-            // Always try default to send to stderr
-            const stderr = std.io.getStdErr().writer();
-            nosuspend stderr.print(level_txt ++ prefix ++ format ++ "\n", args) catch return;
-        },
-    }
+    // Always try default to send to stderr
+    const stderr = std.io.getStdErr().writer();
+    nosuspend stderr.print(level_txt ++ prefix ++ format ++ "\n", args) catch return;
 }
 
 pub const std_options: std.Options = .{