`pihole-FTL --config` sometimes returns the wrong value if `sudo` is not used

[rdwebdesign]

Expected behavior

pihole-FTL --config <option> should return the current value of <option>.
If FTL can't read the current value, an error message or warning should be returned.

Actual behavior / bug

In some cases, when sudo is not used, the command pihole-FTL --config <option> returns the default value for <option>, instead of the current selected value.
No error or warning messages are shown. Just the default value is returned.

Repeating the same command with sudo (sudo pihole-FTL --config <option>), returns the expected value.

This is a problem when Pi-hole user expects to see the current selected value, but is using an OS user without enough permissions and forgets to add sudo.

Note: the issue depends on the user permissions and it happens only in some cases. Some tests returned the expected value even without sudo.

[DL6ER]

Note: the issue depends on the user permissions and it happens only in some cases. Some tests returned the expected value even without sudo.

Yes. I guess the cases it is not working is when /etc/pihole/pihole.toml is correctly owned by user pihole with proper permissions and the user they are using is not able to read the file. sudo trivially bypasses any permission checks.

What is the expected behavior? An error? Falling back to the default when the config file cannot be read is some sensible way, too, but I agree that this can also cause confusion.

[rdwebdesign]

What is the expected behavior? An error?

Personally, I think the intend of pihole-FTL --config <option> command is to return the current value of an option.

In this case, we must return an error message about lack of permissions, when pihole.toml can't be read.

Falling back to the default when the config file cannot be read is some sensible way

I agree this is useful in some cases, but with the current behavior FTL is just giving a returned_value and users can't differentiate between the current value or the default value.
It's impossible to know the permissions failed and the default value was returned.

In this case, we need to at least show a warning saying something like:

returned_value
Warning: pihole.toml can't be read due to missing permissions. Default value was used.