Update pref tests: flag proxy auto-config prefs, and don't flag exten…

…sion sync prefs (bugs 1034298 and 1095899).

validator/testcases/javascript/actions.py

@@ -476,22 +476,25 @@ def _call_create_pref(a, t, e):
     value = str(t(a[0]).get_literal_value())
 
     from predefinedentities import BANNED_PREF_BRANCHES, BANNED_PREF_REGEXPS
-    for banned in BANNED_PREF_BRANCHES:
+    for banned, reason in BANNED_PREF_BRANCHES:
         if value.startswith(banned):
-            return ("Extensions should not alter preferences in the '%s' "
-                    "preference branch" % banned)
+            return reason or ("Extensions should not alter preferences in "
+                              "the '%s' preference branch" % banned)
 
     for banned in BANNED_PREF_REGEXPS:
         if re.match(banned, value):
             return ("Extensions should not alter preferences matching /%s/"
                         % banned)
 
-    if not value.startswith("extensions.") or value.rindex(".") < len("extensions."):
-        return ("Extensions should not alter preferences outside of the "
-                "'extensions.' preference branch. Please make sure that "
-                "all of your extension's preferences are prefixed with "
-                "'extensions.add-on-name.', where 'add-on-name' is a "
-                "distinct string unique to and indicative of your add-on.")
+    for branch in "extensions.", "services.sync.prefs.sync.extensions.":
+        if value.startswith(branch) and value.rindex(".") > len(branch):
+            return
+
+    return ("Extensions should not alter preferences outside of the "
+            "'extensions.' preference branch. Please make sure that "
+            "all of your extension's preferences are prefixed with "
+            "'extensions.add-on-name.', where 'add-on-name' is a "
+            "distinct string unique to and indicative of your add-on.")
 
 
 def _readonly_top(t, r, rn):

validator/testcases/javascript/predefinedentities.py

@@ -19,32 +19,45 @@
                          "instead wherever possible",
 }
 
-BANNED_PREF_BRANCHES = [
-    u"browser.newtab.url",
-    u"browser.newtabpage.enabled",
-    u"browser.preferences.instantApply",
-    u"browser.search.defaultenginename",
-    u"browser.search.searchEnginesURL",
-    u"browser.startup.homepage",
-    u"capability.policy.",
-    u"extensions.alwaysUnpack",
-    u"extensions.blocklist.",
-    u"extensions.bootstrappedAddons",
-    u"extensions.checkCompatibility",
-    u"extensions.dss.",
-    u"extensions.getAddons.",
-    u"extensions.getMoreThemesURL",
-    u"extensions.installCache",
-    u"extensions.lastAppVersion",
-    u"extensions.pendingOperations",
-    u"extensions.update.",
-    u"general.useragent.",
-    u"keyword.URL",
-    u"keyword.enabled",
-    u"network.http.",
-    u"network.websocket.",
-    u"nglayout.debug.disable_xul_cache",
-]
+CUSTOMIZATION_PREF_MESSAGE = (
+    "Extensions must not alter user preferences such as the current home "
+    "page, new tab page, or search engine, without explicit user consent, "
+    "in which a user takes a non-default action. Such changes must also "
+    "be reverted when the extension is disabled or uninstalled.")
+
+BANNED_PREF_BRANCHES = (
+    (u"browser.newtab.url", CUSTOMIZATION_PREF_MESSAGE),
+    (u"browser.newtabpage.enabled", CUSTOMIZATION_PREF_MESSAGE),
+    (u"browser.preferences.instantApply", None),
+    (u"browser.search.defaultenginename", CUSTOMIZATION_PREF_MESSAGE),
+    (u"browser.search.searchEnginesURL", CUSTOMIZATION_PREF_MESSAGE),
+    (u"browser.startup.homepage", CUSTOMIZATION_PREF_MESSAGE),
+    (u"capability.policy.", None),
+    (u"extensions.alwaysUnpack", None),
+    (u"extensions.blocklist.", None),
+    (u"extensions.bootstrappedAddons", None),
+    (u"extensions.checkCompatibility", None),
+    (u"extensions.dss.", None),
+    (u"extensions.getAddons.", None),
+    (u"extensions.getMoreThemesURL", None),
+    (u"extensions.installCache", None),
+    (u"extensions.lastAppVersion", None),
+    (u"extensions.pendingOperations", None),
+    (u"extensions.update.", None),
+    (u"general.useragent.", None),
+    (u"keyword.URL", CUSTOMIZATION_PREF_MESSAGE),
+    (u"keyword.enabled", CUSTOMIZATION_PREF_MESSAGE),
+    (u"network.proxy.autoconfig_url",
+        "As many add-ons have reason to change the proxy autoconfig URL, and "
+        "only one at a time may do so without conflict, extensions must "
+        "make proxy changes using other mechanisms. Installing a proxy "
+        "filter is the recommended alternative: "
+        "https://developer.mozilla.org/en-US/docs/Mozilla/Tech/XPCOM/"
+        "Reference/Interface/nsIProtocolProxyService#registerFilter()"),
+    (u"network.http.", None),
+    (u"network.websocket.", None),
+    (u"nglayout.debug.disable_xul_cache", None),
+)
 
 BANNED_PREF_REGEXPS = [
     r"extensions\..*\.update\.(url|enabled|interval)",

validator/testcases/regex.py

@@ -291,12 +291,12 @@ def tests(self):
                     "Extensions should not alter preferences matching /%s/."
                         % pattern)
 
-        for branch in BANNED_PREF_BRANCHES:
+        for branch, reason in BANNED_PREF_BRANCHES:
             yield self.get_test(
                     branch.replace(r".", r"\."),
                     "Potentially unsafe preference branch referenced",
-                    "Extensions should not alter preferences in the `%s` "
-                    "preference branch" % branch)
+                    reason or ("Extensions should not alter preferences in "
+                               "the `%s` preference branch" % branch))
 
 
 REQUIRE_PATTERN = (r"""(?<!['"])require\s*\(\s*['"]"""