Multi-language search crashes with "index out of bounds" when using 3+ indexed fields

[welpo]

Bug Report

Environment

Zola version: 0.22.1 (also affects current next branch)

Expected Behavior

When building a multi-language site with search enabled and multiple indexed fields (title, description, path, content), the build should complete successfully and generate search indexes for all configured languages.

Example output:

Building site...
-> Creating 76 pages (0 orphan) and 19 sections
Done in 1.7s.

Search indexes created:

• public/search_index.en.js
• public/search_index.es.js

Current Behavior

Build crashes with an index out of bounds panic:

Building site...
-> Creating 76 pages (0 orphan) and 19 sections

thread 'main' panicked at elasticlunr-rs-3.0.2/src/lib.rs:317:37:
index out of bounds: the len is 2 but the index is 2
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Example GH action run: https://github.com/welpo/tabi/actions/runs/21471469174/job/61846221224

Steps to Reproduce

Minimal Configuration

Create a config.toml with:

base_url = "https://example.com"
build_search_index = true

default_language = "en"

[search]
include_title = true
include_description = true
include_path = true
include_content = true

[languages.es]
build_search_index = true

Content Structure

content/
  _index.md
  blog/
    _index.md
    post.md
    post.es.md

Run

zola build

Result

Panic with "index out of bounds: the len is 2 but the index is 2"

Additional context

This is a regression:

• ✅ Zola v0.22.0: Works correctly
• ❌ Zola v0.22.1: Broken
• ❌ Current next branch: Broken

Introduced in: PR #3085 (commit 790de70)

Root cause: Configuration mismatch in components/search/src/elasticlunr.rs where build_fields() uses language_options.search but fill_index() uses config.search, causing field count mismatch when building indexes for non-default languages.

Workarounds:

1. Use only 2 indexed fields (title + content):

   [search]
   include_title = true
   include_description = false
   include_path = false
   include_content = true

2. Disable multi-language search:

   [languages.es]
   build_search_index = false

3. Downgrade to v0.22.0

---

Creating PR to fix this soon.