Re: extension_control_path and "directory"

On Apr 25, 2025, at 17:18, Matheus Alcantara <matheusssilv97(at)gmail(dot)com> wrote:

> Ok, I was testing using extension_control_path = '$system:/my/custom/path'
> (starting with the macro) and it was working as expected, testing with
> the macro at the end does not work.

Great example of why it’s useful to do as much testing as possible! That’s an entirely reasonable place to start testing :-)

> The problem was on find_extension_control_filename() that was appending
> the /extension at the end of the entire extension_control_path GUC value
> instead of just the custom paths.

Oh yeah, lol, that wouldn’t work.

> To append the /extension at each path on extension_control_path would
> require some changes on find_in_path() that
> find_extension_control_filename() calls, which I think that it would
> make the function more complicated. I've them created a similar
> find_in_paths() function that works in the same way but it receives a
> List of paths instead of the string of paths separated by ":". We can
> get this List of paths using get_extension_control_directories() that
> also handle the macro substitution like find_in_path().
>
> Attached v4 with these fixes. I hope that now you should be able to omit
> the /extension from the GUC value.

Yes! It now works with this configuration:

```ini
extension_control_path = '/Users/david/Downloads/share/postgresql:$system'
dynamic_library_path = '/Users/david/Downloads/lib/postgresql:$libdir’
```

Which is nicely more consistent. Kind of want that first one to be called “share_path” now, though, since it’s not just extensions. Although I guess it’s only extension control file searching that uses it (for now).

If I understand this bit correctly:

```c
/* Substitute the path macro if needed */
mangled = substitute_path_macro(piece, "$system", system_dir);

/*
* Append "extension" suffix in case is a custom extension control
* path.
*/
if (strcmp(piece, "$system") != 0)
mangled = psprintf("%s/extension", mangled);
```

The value of `piece` is a single path from the search path, right? If so, I think it’s either `$system` or something else; I don’t it would ever be that `$system` is a substring of a single path. Is that right?

Other than that, I think this patch is good to go. Thanks!

Best,

David

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