Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 42 insertions, 0 deletions

diff --git a/docs/code-quality/lint/linters/eslint-plugin-mozilla/use-isInstance.rst b/docs/code-quality/lint/linters/eslint-plugin-mozilla/use-isInstance.rst
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+use-isInstance
+==============
+
+Prefer ``.isInstance()`` in chrome scripts over the standard ``instanceof``
+operator for DOM interfaces, since the latter will return false when the object
+is created from a different context.
+
+These files are covered:
+
+- ``*.sys.mjs``
+- ``*.jsm``
+- ``*.jsm.js``
+- ``*.xhtml`` with ``there.is.only.xul``
+- ``*.js`` with a heuristic
+
+Since there is no straightforward way to detect chrome scripts, currently the
+linter assumes that any script including the following words are chrome
+privileged. This of course may not be sufficient and is open for change:
+
+- ``ChromeUtils``, but not ``SpecialPowers.ChromeUtils``
+- ``BrowserTestUtils``, ``PlacesUtils``
+- ``document.createXULElement``
+- ``loader.lazyRequireGetter``
+- ``Services.foo``, but not ``SpecialPowers.Services.foo``
+
+Examples of incorrect code for this rule:
+-----------------------------------------
+
+.. code-block:: js
+
+    node instanceof Node
+    text instanceof win.Text
+    target instanceof this.contentWindow.HTMLAudioElement
+
+Examples of correct code for this rule:
+---------------------------------------
+
+.. code-block:: js
+
+    Node.isInstance(node)
+    win.Text.isInstance(text)
+    this.contentWindow.HTMLAudioElement.isInstance(target)