fix: harden config-file include scanning

- Add cycle detection via visited path set to prevent infinite recursion
  on cyclic config-file includes.
- Resolve relative include paths against the parent directory of the
  including config file.
- Strip trailing '?' from optional include paths (Ghostty convention).
- Use UUID-based path for missing file test.
- Add tests for relative includes, optional includes, and cyclic includes.

Sources/GhosttyTerminalView.swift

@@ -1109,9 +1109,10 @@ class GhosttyApp {
             "~/Library/Application Support/com.mitchellh.ghostty/config.ghostty",
         ]
     ) -> Bool {
+        var visited = Set<String>()
         for rawPath in configPaths {
             let path = NSString(string: rawPath).expandingTildeInPath
-            if Self.configFileContainsCodepointMap(atPath: path) {
+            if Self.configFileContainsCodepointMap(atPath: path, visited: &visited) {
                 return true
             }
         }
@@ -1119,11 +1120,21 @@ class GhosttyApp {
     }
 
     /// Scans a single config file (and any files it includes) for
-    /// `font-codepoint-map` entries.
-    private static func configFileContainsCodepointMap(atPath path: String) -> Bool {
-        guard let contents = try? String(contentsOfFile: path, encoding: .utf8) else {
+    /// `font-codepoint-map` entries. Tracks visited paths to prevent
+    /// infinite recursion on cyclic includes.
+    private static func configFileContainsCodepointMap(
+        atPath path: String,
+        visited: inout Set<String>
+    ) -> Bool {
+        let resolved = (path as NSString).standardizingPath
+        guard !visited.contains(resolved) else { return false }
+        visited.insert(resolved)
+
+        guard let contents = try? String(contentsOfFile: resolved, encoding: .utf8) else {
             return false
         }
+        let parentDir = (resolved as NSString).deletingLastPathComponent
+
         for line in contents.components(separatedBy: .newlines) {
             let trimmed = line.trimmingCharacters(in: .whitespaces)
             if trimmed.hasPrefix("#") { continue }
@@ -1133,11 +1144,18 @@ class GhosttyApp {
             if trimmed.hasPrefix("config-file") {
                 let parts = trimmed.split(separator: "=", maxSplits: 1)
                 if parts.count == 2 {
-                    let includePath = parts[1]
+                    var includePath = parts[1]
                         .trimmingCharacters(in: .whitespaces)
                         .trimmingCharacters(in: CharacterSet(charactersIn: "\""))
-                    let resolved = NSString(string: includePath).expandingTildeInPath
-                    if configFileContainsCodepointMap(atPath: resolved) {
+                    // Ghostty supports optional includes with a trailing '?'
+                    if includePath.hasSuffix("?") {
+                        includePath = String(includePath.dropLast())
+                    }
+                    let expanded = NSString(string: includePath).expandingTildeInPath
+                    let absolute = (expanded as NSString).isAbsolutePath
+                        ? expanded
+                        : (parentDir as NSString).appendingPathComponent(expanded)
+                    if configFileContainsCodepointMap(atPath: absolute, visited: &visited) {
                         return true
                     }
                 }

cmuxTests/GhosttyConfigTests.swift

@@ -1431,8 +1431,9 @@ final class GhosttyMouseFocusTests: XCTestCase {
     }
 
     func testUserConfigContainsCJKCodepointMapReturnsFalseForMissingFiles() {
+        let path = NSTemporaryDirectory() + "cmux-nonexistent-\(UUID().uuidString)/config"
         XCTAssertFalse(
-            GhosttyApp.userConfigContainsCJKCodepointMap(configPaths: ["/nonexistent/path/config"])
+            GhosttyApp.userConfigContainsCJKCodepointMap(configPaths: [path])
         )
     }
 
@@ -1452,4 +1453,55 @@ final class GhosttyMouseFocusTests: XCTestCase {
 
         XCTAssertTrue(GhosttyApp.userConfigContainsCJKCodepointMap(configPaths: [main.path]))
     }
+
+    func testUserConfigContainsCJKCodepointMapFollowsRelativeIncludes() throws {
+        let dir = FileManager.default.temporaryDirectory
+            .appendingPathComponent("cmux-test-cjk-rel-\(UUID().uuidString)")
+        try FileManager.default.createDirectory(at: dir, withIntermediateDirectories: true)
+        defer { try? FileManager.default.removeItem(at: dir) }
+
+        let included = dir.appendingPathComponent("fonts.conf")
+        try "font-codepoint-map = U+4E00-U+9FFF=Hiragino Sans\n"
+            .write(to: included, atomically: true, encoding: .utf8)
+
+        let main = dir.appendingPathComponent("config")
+        try "config-file = fonts.conf\n"
+            .write(to: main, atomically: true, encoding: .utf8)
+
+        XCTAssertTrue(GhosttyApp.userConfigContainsCJKCodepointMap(configPaths: [main.path]))
+    }
+
+    func testUserConfigContainsCJKCodepointMapHandlesOptionalInclude() throws {
+        let dir = FileManager.default.temporaryDirectory
+            .appendingPathComponent("cmux-test-cjk-opt-\(UUID().uuidString)")
+        try FileManager.default.createDirectory(at: dir, withIntermediateDirectories: true)
+        defer { try? FileManager.default.removeItem(at: dir) }
+
+        let included = dir.appendingPathComponent("fonts.conf")
+        try "font-codepoint-map = U+4E00-U+9FFF=Hiragino Sans\n"
+            .write(to: included, atomically: true, encoding: .utf8)
+
+        let main = dir.appendingPathComponent("config")
+        try "config-file = \(included.path)?\n"
+            .write(to: main, atomically: true, encoding: .utf8)
+
+        XCTAssertTrue(GhosttyApp.userConfigContainsCJKCodepointMap(configPaths: [main.path]))
+    }
+
+    func testUserConfigContainsCJKCodepointMapHandlesCyclicIncludes() throws {
+        let dir = FileManager.default.temporaryDirectory
+            .appendingPathComponent("cmux-test-cjk-cycle-\(UUID().uuidString)")
+        try FileManager.default.createDirectory(at: dir, withIntermediateDirectories: true)
+        defer { try? FileManager.default.removeItem(at: dir) }
+
+        let fileA = dir.appendingPathComponent("a.conf")
+        let fileB = dir.appendingPathComponent("b.conf")
+        try "config-file = \(fileB.path)\n"
+            .write(to: fileA, atomically: true, encoding: .utf8)
+        try "config-file = \(fileA.path)\n"
+            .write(to: fileB, atomically: true, encoding: .utf8)
+
+        // Should not hang; should return false since neither file has font-codepoint-map
+        XCTAssertFalse(GhosttyApp.userConfigContainsCJKCodepointMap(configPaths: [fileA.path]))
+    }
 }