From 377c5eb43afea30f70c3eeccb84978813fc206bb Mon Sep 17 00:00:00 2001
From: Henrik Skupin <mail@hskupin.info>
Date: Thu, 13 Apr 2023 16:18:24 +0000
Subject: [PATCH] Bug 1776190 - [marionette] Allow a modifier key to be reset
 when sending it again within the same command.
 r=webdriver-reviewers,jdescottes

Differential Revision: https://phabricator.services.mozilla.com/D175242
---
 remote/marionette/event.sys.mjs               |  7 +++++-
 .../webdriver/element_send_keys/__init__.py   |  0
 .../webdriver/element_send_keys/send_keys.py  | 24 +++++++++++++++++++
 3 files changed, 30 insertions(+), 1 deletion(-)
 create mode 100644 testing/web-platform/mozilla/tests/webdriver/element_send_keys/__init__.py
 create mode 100644 testing/web-platform/mozilla/tests/webdriver/element_send_keys/send_keys.py

diff --git a/remote/marionette/event.sys.mjs b/remote/marionette/event.sys.mjs
index 45570d3cb0b7..e01f1203dcab 100644
--- a/remote/marionette/event.sys.mjs
+++ b/remote/marionette/event.sys.mjs
@@ -262,7 +262,12 @@ event.sendKeys = function(keyString, win) {
     const data = lazy.keyData.getData(keyValue);
     const key = { ...data, ...modifiers };
     if (data.modifier) {
-      modifiers[data.modifier] = true;
+      // Negating the state of the modifier here is not spec compliant but
+      // makes us compatible to Chrome's behavior for now. That's fine unless
+      // we know the correct behavior.
+      //
+      // @see: https://github.com/w3c/webdriver/issues/1734
+      modifiers[data.modifier] = !modifiers[data.modifier];
     }
     event.sendSingleKey(key, win);
   }
diff --git a/testing/web-platform/mozilla/tests/webdriver/element_send_keys/__init__.py b/testing/web-platform/mozilla/tests/webdriver/element_send_keys/__init__.py
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/testing/web-platform/mozilla/tests/webdriver/element_send_keys/send_keys.py b/testing/web-platform/mozilla/tests/webdriver/element_send_keys/send_keys.py
new file mode 100644
index 000000000000..1399959cebf9
--- /dev/null
+++ b/testing/web-platform/mozilla/tests/webdriver/element_send_keys/send_keys.py
@@ -0,0 +1,24 @@
+from tests.support.asserts import assert_success
+from tests.support.keys import Keys
+
+
+def element_send_keys(session, element, text):
+    return session.transport.send(
+        "POST",
+        "/session/{session_id}/element/{element_id}/value".format(
+            session_id=session.session_id, element_id=element.id
+        ),
+        {"text": text},
+    )
+
+
+def test_modifier_key_toggles(session, inline, modifier_key):
+    session.url = inline("<input type=text value=foo>")
+    element = session.find.css("input", all=False)
+
+    response = element_send_keys(
+        session, element, f"{modifier_key}a{modifier_key}{Keys.DELETE}cheese"
+    )
+    assert_success(response)
+
+    assert element.property("value") == "cheese"