Merge default language data with section language data

[vcrn]

Resolves #1918

When there is a merge conflict, I went with causing a panic right away and not returning anything if everything went well, instead of bail at conflict and returning an Ok() if everything went well. If you want this changed to the latter approach, just let me know.

I don't seem to be able to directly manipulate languagesi[default_language], which is why I'm cloning it, manipulating it via .merge() and then using .insert().

The test add_default_language_skips_insert() doesn't check that insert actually hasn't been performed, it is only when running it manually that a person can check and see that a warning message hasn't been printed. I used it for my testing and left it, but we can remove it if you want to.

Also, under method add_default_language() there was some TODO comments. This PR might solve it but I'm not sure, so I've left it.

[Keats]

I think that's not the right way to do it. We should handle that before adding the default language struct in this line: https://github.com/getzola/zola/blob/next/components/config/src/config/mod.rs#L128

[vcrn]

Thanks for the feedback! It seems clear for me how to proceed.

Edit:

I think that's not the right way to do it. We should handle that before adding the default language struct in this line: https://github.com/getzola/zola/blob/next/components/config/src/config/mod.rs#L128

This one I'm a bit uncertain about though. Which part are you referring to that should be handled before adding the default language struct, @Keats?

[vcrn]

Fixing my broken logic, I went with a slightly more complicated route than I first imagined, in order to not do a merge unless necessary. If you think we should go with a simpler route, I propose something like this:

        if let Some(section_default_language_options) = self.languages.get(&self.default_language) {
            if base_default_language_options != languages::LanguageOptions::default() {
                println!("Warning: config.toml contains both default language specific information at base and under section `[languages.{}]`, \
                    which may cause merge conflicts. Please use only one to specify language specific information", self.default_language);
            }
            base_default_language_options.merge(section_default_language_options)?;
        }
        self.languages.insert(self.default_language.clone(), base_default_language_options);

        Ok(()

[vcrn]

Just wanted to check whether you believe you'll have time to check out the updated PR any time soon, @Keats ?

[Keats]

It's ok I think. I'll change some style stuff later after merging but I think we should at least correcly test the errors before merging.

[vcrn]

@Keats, I've updated the test in question. I also took a second look at your test names and gave mine ones that are more in line with yours. I also changed some of the variable names in the new tests so they are more descriptive.

[Keats]

Thanks!