Not getting proper error message from `PostgrestBuilder`

[Juned Khatri]

Bug report

• [✓] I confirm this is a bug with Supabase, not with my own application.
• [✓] I confirm I have searched the Docs, GitHub Discussions, and Discord.

Describe the bug

When fetch function inside PostgrestBuilder fails. The error does not contain proper information why the fetch failed.

To Reproduce

Steps to reproduce the behavior, please provide code snippets or a repository:

1. Put postgrest server behind self signed certificate
2. Run database query

   const { data: somedata, error } = supabase
       .from('sometable')
       .select('*')
       .order('somecolumn', { ascending: false })
   

3. Getting error message like the below
   
4. It is not very clear what the error is

Expected behavior

The error should contain clear information that the error is we are not able to verify certificate

Screenshots

If applicable, add screenshots to help explain your problem.

System information

• OS: macOS
• Browser (if applies): NextJS server component
• Version of supabase-js: 2.25.0
• Version of Node.js: 18.18.2

Additional context

After spending 2 hours digging through internal library I found out that the error is self signed certificate is not being verified properly (Self signed cert is added properly in container's /etc/ssl/certs/ca-certificates.crt path. That is also an issue but I will deal with it separately.)

The point is I found where exactly the problem is. It is in src/PostgrestBuilder.ts inside then function. res object's error contains another error named cause that contains more information about the error. Which is getting lost. Because it is not getting assigned in new error object.

[Ted Scharff]

This problem hit me too. There's not way to determine the cause of the fetch error or handle it.

I'd suggest either propogating the original error:

return {
  error: fetchError,
  data: null,
  ...
}

Or a new error encapsulating the original error in its cause property:

return {
  error: new Error("Fetch Failed", {cause: fetchError}),
  ...
}