thunderbird: add native host support (#6292)

Note: the test case uses a firefox native host but it shouldn't matter
since they are packaged the same way for both TB and Firefox.

modules/programs/thunderbird.nix

@@ -136,6 +136,24 @@ let
     '') prefs)}
     ${extraPrefs}
   '';
+
+  nativeMessagingHostsPath = if isDarwin then
+    "${cfg.vendorPath}/NativeMessagingHosts"
+  else
+    "${cfg.vendorPath}/native-messaging-hosts";
+
+  nativeMessagingHostsJoined = pkgs.symlinkJoin {
+    name = "th_native-messaging-hosts";
+    paths = [
+      # Link a .keep file to keep the directory around
+      (pkgs.writeTextDir "lib/mozilla/native-messaging-hosts/.keep" "")
+      # Link package configured native messaging hosts (entire mail app actually)
+      cfg.package
+    ]
+    # Link user configured native messaging hosts
+      ++ cfg.nativeMessagingHosts;
+  };
+
 in {
   meta.maintainers = with hm.maintainers; [ d-dervishi jkarlson ];
 
@@ -158,6 +176,29 @@ in {
         description = "profile version, set null for nix-darwin";
       };
 
+      vendorPath = mkOption {
+        internal = true;
+        type = with types; nullOr str;
+        # Thunderbird doesn't look in `Application Support` on macOS for user
+        # config (in contrast to global settings that are the same for Firefox
+        # and Thunderbird):
+        # https://developer.thunderbird.net/add-ons/mailextensions/supported-webextension-api
+        default = if isDarwin then "Library/Mozilla" else ".mozilla";
+        example = ".mozilla";
+        description =
+          "Directory containing the native messaging hosts directory.";
+      };
+
+      nativeMessagingHosts = optionalAttrs (cfg.vendorPath != null) (mkOption {
+        visible = true;
+        type = types.listOf types.package;
+        default = [ ];
+        description = ''
+          Additional packages containing native messaging hosts that should be
+          made available to Thunderbird extensions.
+        '';
+      });
+
       profiles = mkOption {
         type = with types;
           attrsOf (submodule ({ config, name, ... }: {
@@ -403,7 +444,13 @@ in {
     home.file = mkMerge ([{
       "${thunderbirdConfigPath}/profiles.ini" =
         mkIf (cfg.profiles != { }) { text = generators.toINI { } profilesIni; };
-    }] ++ flip mapAttrsToList cfg.profiles (name: profile: {
+    }] ++ optional (cfg.vendorPath != null) {
+      "${nativeMessagingHostsPath}" = {
+        source =
+          "${nativeMessagingHostsJoined}/lib/mozilla/native-messaging-hosts";
+        recursive = true;
+      };
+    } ++ flip mapAttrsToList cfg.profiles (name: profile: {
       "${thunderbirdProfilesPath}/${name}/chrome/userChrome.css" =
         mkIf (profile.userChrome != "") { text = profile.userChrome; };
 

tests/modules/programs/thunderbird/thunderbird.nix

@@ -41,6 +41,9 @@
     # Disable warning so that platforms' behavior is the same
     darwinSetupWarning = false;
 
+    # Darwin doesn't support wrapped Thunderbird, using unwrapped instead
+    package = pkgs.thunderbird-unwrapped;
+
     profiles = {
       first = {
         isDefault = true;
@@ -62,18 +65,31 @@
       };
     };
 
+    nativeMessagingHosts = with pkgs;
+      [
+        # NOTE: this is not a real Thunderbird native host module but Firefox; no
+        # native hosts are currently packaged for nixpkgs or elsewhere, so we
+        # have to improvise. Packaging wise, Firefox and Thunderbird native hosts
+        # are identical though. Good news is that the test will still pass as
+        # long as we don't attempt to run the mail client itself with the host.
+        # (Which we don't.)
+        browserpass
+      ];
+
     settings = {
       "general.useragent.override" = "";
       "privacy.donottrackheader.enabled" = true;
     };
   };
 
-  test.stubs.thunderbird = { };
-
   nmt.script = let
     isDarwin = pkgs.stdenv.hostPlatform.isDarwin;
     configDir = if isDarwin then "Library/Thunderbird" else ".thunderbird";
     profilesDir = if isDarwin then "${configDir}/Profiles" else "${configDir}";
+    nativeHostsDir = if isDarwin then
+      "Library/Mozilla/NativeMessagingHosts"
+    else
+      ".mozilla/native-messaging-hosts";
     platform = if isDarwin then "darwin" else "linux";
   in ''
     assertFileExists home-files/${configDir}/profiles.ini
@@ -95,5 +111,7 @@
     assertFileExists home-files/${profilesDir}/first/chrome/userContent.css
     assertFileContent home-files/${profilesDir}/first/chrome/userContent.css \
       <(echo "* { color: red !important; }")
+
+    assertFileExists home-files/${nativeHostsDir}/com.github.browserpass.native.json
   '';
 }