Error when title = null for the current language

[axelkar]

Summary and motivation

With this config (trying to achieve /en/ and /fi/ without either of them being at top-level)

# top-level "title" missing
default_language = "zz"

[languages.en]
title = "tabi"
[languages.fi]
title = "tabi"

Zola returns this fairly cryptic error:

Error: Failed to build the site
Error: Failed to render '404.html' (error happened in 'base.html').
Error: Reason: Tried to concat a value that is not a string or a number from ident prefix

In reality it happens in template/partials/title.html:

{%- set prefix = config.title | safe -%}
...
{{- suffix ~ separator ~ prefix -}}

Implementation details

Somewhere in templates/partials/title.html. I have no idea how you can throw an error in Tera, and I guess making the error better would be in the scopes of Tera and Zola

Checklist

• I've searched existing issues to make sure this feature hasn't already been requested.
• This feature aligns with tabi's philosophy (minimal JS, accessible…)
• I'm willing to contribute to the implementation of this feature.

[welpo]

Hi!

That is a cryptic error message.

Are you interested in using tabi without a default title? Or is the request "improve error message when title is missing"?

To throw an error in tera, you can use throw:

{{ throw(message="ERROR: No `title` set in `config.toml`. tabi requires a title to function properly.") }}

[welpo]

Oh, and I'm curious about your setup. What do you expect the base URL to contain? A reference/link to the other languages? I hadn't thought of such a setup.

[axelkar]

This issue is just about the error being hard to debug. I moved title to languages.en.title and got this error.

I currently set the default language to zz and have a language switcher in content/_index.md. I might set Nginx to redirect with the Accept-Language header, and otherwise default to /en/ (content/_index.en.md).

I'll delete that language from the language picker and 404 page and change all other references to x-default the using regex in my website's Nix derivation/builder.

The zz-trick is from here: getzola/zola#1660

Maybe this is something Tabi would like to support?

Here's the Nix flake for my website's HTML/Zola portion if you're interested:

# combined with the correct lockfile and Nix installed, this "just works". the first argument is implied to be something like ".#packages.x86-64-linux.default"
nix build
# When hosted on a GitHub repo (mine currently isn't)
nix build 'github:axelkar/example-website-flake'
# Launch the development shell
nix develop

# .envrc (https://direnv.net/) for loading up the development shell
use flake

# flake.nix
{
  description = "Axel Karjalainen's personal website";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.11";
    nixpkgs-unstable.url = "github:NixOS/nixpkgs/nixos-unstable"; # for Zola v0.20.0, stable only has v0.19.2
    flake-utils.url = "github:numtide/flake-utils";
    tabi = {
      url = "github:welpo/tabi";
      flake = false;
    };
  };

  outputs = { self, nixpkgs, nixpkgs-unstable, flake-utils, tabi, ... }: flake-utils.lib.eachDefaultSystem (system:
    let
      pkgs = nixpkgs.legacyPackages.${system};
      pkgsUnstable = nixpkgs-unstable.legacyPackages.${system};
      theme = tabi;
      themeName = ((builtins.fromTOML (builtins.readFile "${theme}/theme.toml")).name);
    in
    {
      packages.default = pkgs.stdenvNoCC.mkDerivation rec {
        pname = "axka-fi-static";
        version = "2025-03-05";
        src = ./axka.fi-zola;
        nativeBuildInputs = [ pkgsUnstable.zola pkgs.just pkgs.typst ];
        configurePhase = ''
          mkdir -p "themes/${themeName}"
          cp -r ${theme}/* "themes/${themeName}"
          #just build-typst-images
        '';
        # FIXME: typst is failing without network access

        # TODO:
        # zz -> x-default https://developers.google.com/search/docs/specialty/international/localized-versions#xdefault
        # Error when remove and substitute don't do anything
        # remove zz langpicker in 404.html (<div class=dropdown-content role=menu>zz)
        # substitute <html lang=zz> -> en in 404.html
        # remove zz lines in 404.html
        # remove zz langpicker everywhere else
        # susbtitute zz -> x-default everywhere else
        buildPhase = "zola build";

        installPhase = "cp -r public $out";
      };
      devShells.default = pkgs.mkShellNoCC {
        buildInputs = [ pkgsUnstable.zola pkgs.just pkgs.typst ];
        shellHook = ''
          mkdir -p themes
          ln -sfn "${theme}" "axka.fi-zola/themes/${themeName}"
        '';
      };
    });
}

[welpo]

This issue is just about the error being hard to debug

Gotcha! Fixed in a384ac8

Maybe this is something Tabi would like to support?

In what way?

[axelkar]

Maybe this is something Tabi would like to support?

In what way?

Maybe add an option to ignore the default language in the language picker, 404 page and anything similar, and rename it in the meta tags to x-default? Or do this automatically when zz is provided.

[welpo]

@axelkar I'm not sure; your setup seems quite specific to you.

For other users, I can imagine the main page for the default language not having content and just showing links to the languages.

However: how about the menu links? Ideally they wouldn't show up if there isn't a corresponding page, but tabi currently assumes all menu items (top right) do exist.

Same with the language picker: it'll 404.

I'd like to fix those issues first, I think (and I'd take a PR for either)

[axelkar]

For other users, I can imagine the main page for the default language not having content and just showing links to the languages.

However: how about the menu links? Ideally they wouldn't show up if there isn't a corresponding page, but tabi currently assumes all menu items (top right) do exist.

Same with the language picker: it'll 404.

On the root page (https://example.com/), I hid the navbar (using CSS, not perfect) and added big buttons redirecting to the different language pages (e.g. https://example.com/en/)

[welpo]

Hmm not ideal.

I'd rather wait to see if more people request this. Ideally, the Zola discussion you linked would find a resolution that tabi could adapt to.