MacOS install error

[geomlattice]

Hello

I have run mix desktop.installer on a Macbook after following the xcode setup guide here.

I am currently getting the following error:

Running: strip -x -S /Users/$USER/$PREFIX/desktop-example-app/_build/prod/rel/default_release/lib/asn1-5.4.3/priv/lib/asn1rt_nif.so
error: /Library/Developer/CommandLineTools/usr/bin/strip: file: /Users/$USER/$PREFIX/desktop-example-app/_build/prod/rel/default_release/lib/asn1-5.4.3/priv/lib/asn1rt_nif.so is not writable (Permission denied)
** (MatchError) no match of right hand side value:

    {"", 1}

    (desktop_deployment 1.0.0) lib/tooling.ex:124: Desktop.Deployment.Tooling.cmd!/2
    (desktop_deployment 1.0.0) lib/tooling.ex:80: Desktop.Deployment.Tooling.strip_symbols/1
    (desktop_deployment 1.0.0) lib/package/macos.ex:12: anonymous fn/2 in Desktop.Deployment.Package.MacOS.import_extra_files/1
    (elixir 1.19.5) lib/enum.ex:2520: Enum."-reduce/3-lists^foldl/2-0-"/3
    (desktop_deployment 1.0.0) lib/package/macos.ex:12: Desktop.Deployment.Package.MacOS.import_extra_files/1
    (desktop_deployment 1.0.0) lib/deployment.ex:39: Desktop.Deployment.generate_installer/1
    (mix 1.19.5) lib/mix/tasks/release.ex:1086: Mix.Tasks.Release.run_steps/1
    (mix 1.19.5) lib/mix/task.ex:499: anonymous fn/3 in Mix.Task.run_task/5

Not sure what is going on. Any insight is appreciated!

[dominicletz]

@cursor based on the stacktrace what is happening here? Also why do we see $USER/$PREFIX in the output instead of real values. Has the user provided it this way or is this from the code?

[cursor]

---

Analysis of the stacktrace

1. What’s happening

The failure comes from a permission error when running strip on macOS during the installer build.

Flow:

1. MacOS.import_extra_files/1 (line 12 in macos.ex): collects all .dylib and .so files in the release and calls strip_symbols/1 for each.

2. Tooling.strip_symbols/1 (line 80 in tooling.ex): for macOS libraries, runs strip -x -S <file> to remove symbols and shrink binaries.

3. strip fails with:

   file: .../asn1rt_nif.so is not writable (Permission denied)
   

4. Tooling.cmd!/2 (line 124 in tooling.ex): expects {ret, 0} from System.cmd/2:

   def cmd!(cmd, args) do
     {ret, 0} = cmd_raw(cmd, args)  # Expects exit code 0
     ret
   end

   When strip fails, it returns exit code 1. cmd_raw returns {"", 1}, so {ret, 0} fails and raises the MatchError.

So the root cause is that strip cannot modify the file because of permissions. Common reasons:

• Files are in a read-only directory (e.g. under _build).
• Files were copied from a location that left them read-only.
• Directory/file permissions prevent write access.
• Running without enough privileges.

2. $USER and $PREFIX in the error

$USER and $PREFIX are not produced by the deployment code.

The deployment package uses paths from Mix.Release.path, which come from Mix and contain real values. The deployment code does not construct paths using $USER or $PREFIX.

So the $USER and $PREFIX in the error message are almost certainly user redactions when copying the log, e.g. replacing /Users/johndoe/projects/desktop-example-app/ with /Users/$USER/$PREFIX/desktop-example-app/ for privacy.

---

Suggested fix

Make the file writable before strip so it can modify it in-place. In tooling.ex, the file_replace function already does something similar with File.chmod!/2:

 def file_replace(file, from, to) do
 orig = File.read!(file)
 content = String.replace(orig, from, to)

 if orig != content do
 File.chmod!(file, Bitwise.bor(File.lstat!(file).mode, 0o200))  # <-- Makes writable
 File.write!(file, content)
 end

strip_symbols/1 could be updated to ensure the file is writable before calling strip, using a similar File.chmod! pattern. The desktop_deployment project lives in a separate repo (elixir-desktop/deployment), so that change would need to be made there.

  

[geomlattice]

I added $USER/$PREFIX to conceal information on my system that is not needed to understand the error at hand