firefox: wrapper updating an addon perserves addon settings

doc/builders/packages/firefox.section.md

@@ -9,7 +9,7 @@ The `wrapFirefox` function allows to pass policies, preferences and extension th
   myFirefox = wrapFirefox firefox-unwrapped {
     nixExtensions = [
       (fetchFirefoxAddon {
-        name = "ublock";
+        name = "ublock"; # Has to be unique!
         url = "https://addons.mozilla.org/firefox/downloads/file/3679754/ublock_origin-1.31.0-an+fx.xpi";
         sha256 = "1h768ljlh3pi23l27qp961v1hd0nbj2vasgy11bmcrlqp40zgvnr";
       })
@@ -42,7 +42,7 @@ The `wrapFirefox` function allows to pass policies, preferences and extension th
 If `nixExtensions != null` then all manually installed addons will be uninstalled from your browser profile.
 To view available enterprise policies visit [enterprise policies](https://github.com/mozilla/policy-templates#enterprisepoliciesenabled)
 or type into the Firefox url bar: `about:policies#documentation`.
-Nix installed addons do not have a valid signature, which is why signature verification is disabled. This does not compromise security because downloaded addons are checksumed and manual addons can't be installed.
+Nix installed addons do not have a valid signature, which is why signature verification is disabled. This does not compromise security because downloaded addons are checksumed and manual addons can't be installed. Also make sure that the `name` field of fetchFirefoxAddon is unique. If you remove an addon from the nixExtensions array, rebuild and start Firefox the removed addon will be completly removed with all of its settings.
 
 ## Troubleshooting {#sec-firefox-troubleshooting}
 If addons do not appear installed although they have been defined in your nix configuration file reset the local addon state of your Firefox profile by clicking `help -> restart with addons disabled -> restart -> refresh firefox`. This can happen if you switch from manual addon mode to nix addon mode and then back to manual mode and then again to nix addon mode.

pkgs/applications/networking/browsers/firefox/wrapper.nix

@@ -1,5 +1,5 @@
 { stdenv, lib, makeDesktopItem, makeWrapper, lndir, config
-, replace, fetchurl, zip, unzip, jq, xdg_utils
+, replace, fetchurl, zip, unzip, jq, xdg_utils, writeText
 
 ## various stuff that can be plugged in
 , flashplayer, hal-flash
@@ -97,12 +97,17 @@ let
       #   EXTRA PREF CHANGES  #
       #                       #
       #########################
-      policiesJson = builtins.toFile "policies.json"
-        (builtins.toJSON enterprisePolicies);
+      policiesJson = writeText "policies.json" (builtins.toJSON enterprisePolicies);
 
       usesNixExtensions = nixExtensions != null;
 
-      extensions = builtins.map (a:
+      nameArray = builtins.map(a: a.name) (if usesNixExtensions then nixExtensions else []);
+
+      # Check that every extension has a unqiue .name attribute
+      # and an extid attribute
+      extensions = if nameArray != (lib.unique nameArray) then
+        throw "Firefox addon name needs to be unique"
+      else builtins.map (a:
         if ! (builtins.hasAttr "extid" a) then
         throw "nixExtensions has an invalid entry. Missing extid attribute. Please use fetchfirefoxaddon"
         else
@@ -128,12 +133,19 @@ let
                 };
               }
             ) {} extensions;
-        }
+          } //
+          {
+            Extensions = {
+              Install = lib.foldr (e: ret:
+                ret ++ [ "${e.outPath}/${e.extid}.xpi" ]
+                ) [] extensions;
+            };
+          }
         // extraPolicies;
       };
 
-      mozillaCfg = builtins.toFile "mozilla.cfg" ''
-// First line must be a comment
+      mozillaCfg =  writeText "mozilla.cfg" ''
+        // First line must be a comment
 
         // Disables addon signature checking
         // to be able to install addons that do not have an extid
@@ -320,18 +332,13 @@ let
         # preparing for autoconfig
         mkdir -p "$out/lib/${firefoxLibName}/defaults/pref"
 
-        cat > "$out/lib/${firefoxLibName}/defaults/pref/autoconfig.js" <<EOF
-          pref("general.config.filename", "mozilla.cfg");
-          pref("general.config.obscure_value", 0);
-        EOF
+        echo 'pref("general.config.filename", "mozilla.cfg");' > "$out/lib/${firefoxLibName}/defaults/pref/autoconfig.js"
+        echo 'pref("general.config.obscure_value", 0);' >> "$out/lib/${firefoxLibName}/defaults/pref/autoconfig.js"
 
         cat > "$out/lib/${firefoxLibName}/mozilla.cfg" < ${mozillaCfg}
 
         mkdir -p $out/lib/${firefoxLibName}/distribution/extensions
 
-        for i in ${toString extensions}; do
-          ln -s -t $out/lib/${firefoxLibName}/distribution/extensions $i/*
-        done
         #############################
         #                           #
         #   END EXTRA PREF CHANGES  #

pkgs/build-support/fetchfirefoxaddon/default.nix

@@ -1,16 +1,20 @@
 {stdenv, lib, coreutils, unzip, jq, zip, fetchurl,writeScript,  ...}:
-{ name
+
+{
+  name
 , url
 , md5 ? ""
 , sha1 ? ""
 , sha256 ? ""
 , sha512 ? ""
+, fixedExtid ? null
 , hash ? ""
 }:
+
 stdenv.mkDerivation rec {
 
   inherit name;
-  extid = "${src.outputHash}@${name}";
+  extid = if fixedExtid == null then "nixos@${name}" else fixedExtid;
   passthru = {
     exitd=extid;
   };
@@ -35,4 +39,3 @@ stdenv.mkDerivation rec {
   };
   nativeBuildInputs = [ coreutils unzip zip jq  ];
 }
-