From 19c18672af61609ec18338f283854b44878a8a55 Mon Sep 17 00:00:00 2001
From: girst <girst@users.noreply.github.com>
Date: Thu, 18 Nov 2021 15:20:53 +0100
Subject: [PATCH] make Fission check more strict

only warn when fission.webContentIsolationStrategy > 0 (i.e. when remote
subframes are enabled)
---
 documentation/known-bugs.md | 34 +++++++++++++++-------------------
 extension/lib/main.coffee   | 13 +++++++------
 2 files changed, 22 insertions(+), 25 deletions(-)

diff --git a/documentation/known-bugs.md b/documentation/known-bugs.md
index 041b723..30ed834 100644
--- a/documentation/known-bugs.md
+++ b/documentation/known-bugs.md
@@ -21,28 +21,24 @@ The [new RDM] does not have this bug; it can be enabled by switching
 
 ## Fission
 
-**Affected**: some Nightly users, future versions  
-**Workaround**: `fission.autostart;false`
+**Affected**: Firefox >= 96  
+**Workaround**: `fission.webContentIsolationStrategy;0`
 
 With [Fission] enabled, VimFx can't inspect out-of-process iframes.
 
-Fission, sometimes called *Site Isolation*, is not (yet) turned on by default,
-but can be disabled by switching `fission.autostart` to `false` in
-`about:config`. With Fission, VimFx cannot place hint markers or determine
-whether an editable element is active in iframes from a different domain to the
-top document. We will instead enter insert mode whenever such an iframe is
-active (so input elements are usable; hit Escape or click outside the iframe to
-let VimFx re-gain control).
-
-<!-- Mozilla are doing a/b testing on around 5% of Nightly 83+ installations,
-where they enable Fission.
-https://bugzilla.mozilla.org/show_bug.cgi?id=1660366 -->
-
-<!-- For full OOP-iframe support it is way too early.
-As of May 2020, not even Firefox' DevTools support it, let alone other Vim
-like (web)extensions. Further, I suspect that to avoid a huge rewrite of how
-VimFx handles element discovery and interaction, we'd need cross-process-DOM
-APIs that just don't exist right now. -->
+With Fission, sometimes called *Site Isolation*, VimFx cannot place hint markers
+or detect input elements inside iframes from a different domain to the top
+document. We will instead enter insert mode whenever such an iframe is active.
+Hit Escape or click outside the iframe to let VimFx re-gain control. Setting
+`fission.webContentIsolationStrategy` to `0` in `about:config` only disables the
+iframe part of Fission, but is available only since Firefox 94. Some Nightly
+installations were opted into Fission earlier; set `fission.autostart`
+to `false` if the main workaround is unavailable.
+
+<!-- VimFx will probably never support Fission. Its architecture assumes that
+all elements can be interacted with from a single point. It would require
+revisiting 8a33140f and injecting a script into each frame and postMessage'ing
+them instead of directly accessing elements within them. -->
 
 [Fission]: https://wiki.mozilla.org/Project_Fission
 
diff --git a/extension/lib/main.coffee b/extension/lib/main.coffee
index 7417dc7..a49d548 100644
--- a/extension/lib/main.coffee
+++ b/extension/lib/main.coffee
@@ -117,14 +117,15 @@ module.exports = (data, reason) ->
       )
 
       # check whether Fission is enabled, and warn the user if so.
-      FISSION_ENABLED_PREF = 'fission.autostart'
+      FISSION_ENABLED_PREF = 'fission.autostart' # fx68+
+      FISSION_ISOLATION_PREF = 'fission.webContentIsolationStrategy' # fx94+
       IGNORE_FISSION_PREF = 'ignore_fission'
       isFissionWindow = window.docShell.nsILoadContext.useRemoteSubframes
-      isFissionEnabled = Services.appinfo.fissionAutostart and # current session
-        prefs.root.get(FISSION_ENABLED_PREF) # future sessions
-      isFissionIgnored = prefs.has(IGNORE_FISSION_PREF) and
-        prefs.get(IGNORE_FISSION_PREF) == true
-      if isFissionWindow and isFissionEnabled and not isFissionIgnored
+      isFissionEnabled = prefs.root.get(FISSION_ENABLED_PREF)
+      isIsolateNothing = (try prefs.root.get(FISSION_ISOLATION_PREF)) == 0
+      isFissionIgnored = (try prefs.get(IGNORE_FISSION_PREF)) == true
+      if isFissionWindow and isFissionEnabled and not isIsolateNothing and
+          not isFissionIgnored
         console.error('VimFx: Fission is enabled in your browser.'
           'VimFx will not be able to interact with third party iframes.')
         console.info("Please consult VimFx' documentation on Known Bugs.")
-- 
2.39.3