Signal doesn't launch after apllying themes

signal doesnt start after putting @import "catppuccin-.css" in manifest.css nor does it launch when using theme-injector.
Had to reinstall both times

[undefinedcode0]

Have you found any fix? This is also happening to me

unfortunately no, didnt have much time recently to look into it will most likely give it another try or smth if i fix ill let you know

[TheSunCat]

I did some debugging and found that (at least on NixOS) Signal is failing to find libpulse.so.0 which is preventing it from launching. Setting LD_LIBRARY_PATH allows it to find it, and it opens the window which shows the Signal loading animation infinitely.
Further checking the JavaScript console (using --enable-dev-tools), I found it fails to load libstdc++.so. Adding a path to this lib in LD_LIBRARY_PATH finally allows Signal to launch normally and have the theme applied.

This is a rather dirty workaround, but as I am not familiar with how Electron works I am not sure I can do more. I will do some more research and write what I find here.

[TheSunCat]

Got it, by reading the Nix package here: https://github.com/NixOS/nixpkgs/blob/db8414903dd6b3042e1ac471eafc18ca4ccb54a4/pkgs/by-name/si/signal-desktop/generic.nix#L246-L249

Apparently Signal does not "pack" their .node directory. Adding --unpack '*.node' to the pack command allows it to start up fine for me. See commit: https://git.allpurposem.at/mat/Computer/commit/d0d31a75e85fb1758ba43e74aeeb69da109630fc

[Intiiii]

any way to fix this on windows?

[FunkeymonkeyTTR]

Signal doesn't launch for me at all on windows after editing the manifest.css, even after I reverse the edit, it needs a full reinstall to function again.

[sciloop]

What a waste of time! Could you please eliminate the windows option until that works again?!

[hoodrichpirobo]

same happened for me

[sofiedotcafe]

Got it, by reading the Nix package here: https://github.com/NixOS/nixpkgs/blob/db8414903dd6b3042e1ac471eafc18ca4ccb54a4/pkgs/by-name/si/signal-desktop/generic.nix#L246-L249

Apparently Signal does not "pack" their .node directory. Adding --unpack '*.node' to the pack command allows it to start up fine for me. See commit: https://git.allpurposem.at/mat/Computer/commit/d0d31a75e85fb1758ba43e74aeeb69da109630fc

On Nix, you may also just skip the asar junk and do this, because you are in control of the build toolchain.

signal-desktop =
  (lib.makeOverridable (
    {
      theme ? null,
    }:
    signal-desktop.overrideAttrs (prev: {
      postPatch =
        (prev.postPatch or "")
        + (lib.throwIf (theme == null || builtins.typeOf theme != "string")
          "signal-desktop: theme must be null or a string for a path (got ${builtins.typeOf theme})"
          (
            lib.optionalString (theme != null) ''
              sed -i '1i @use "${theme}" as *;' stylesheets/manifest.scss
            ''
          )
        );
    })
  ))
    { };

I added the lib.makeOverridable so I can do something like this:

(signal-desktop.override { theme = "${pkgs.catppuccin-signal.override { variant = "mocha"; }}"; })

The package for catppuccin-signal is as follows:

{
  fetchFromGitHub,
  writeText,
  variant ? "mocha",
}:

let
  src = fetchFromGitHub {
    owner = "CalfMoon";
    repo = "signal-desktop";
    rev = "main";
    hash = "sha256-dWT3hG2uGhwpNgGHjwVmzci68upUVe5ktoeaPrNZ3q8=";
  };
in
writeText "catppuccin-signal.css" (builtins.readFile (src + "/themes/catppuccin-${variant}.css"))

[toshgoodson]

For those still having this issue, the specific problem seems to be a checksum mismatch. I don't know where this is stored on Windows, but on macOS it's in the Signal.app/Contents/Info.plist file under the ElectronAsarIntegrity key.

Also, for some reason the checksum that the asar integrity check expects is different than the one I calculated for the app.asar file itself, so I don't know what's going on there. But thankfully running Signal from the terminal outputs the checksum that should be used (it's the second value):

> ../MacOS/Signal
[1915:0412/110452.912487:FATAL:electron/shell/common/asar/asar_util.cc:143] Integrity check failed for asar archive (ade238e591db191adaac25610f0a0c7e279fc7f49cc5ca73ff80a6844d3fb5d8 vs 3fcca83e813da60baa287ea12390409641dec45dca7f9dbf3ec4a29bb1f19161)
[1]    1915 trace trap  ../MacOS/Signal

Once I changed the checksum value in the plist file, Signal started up fine.