Publishing a second "Hola mundo" through the CMS broke the first one's page:
it rendered the article, then a second copy of the entire site. Three silent
failures lined up.
Decap could not write hola-mundo.es.md twice, so it wrote hola-mundo.es-1.md.
That suffix is not a language, so Hugo stopped treating the file as a Spanish
sibling and translate.py's split_lang() skipped it — the post went live in
Spanish alone, and no German or Portuguese was ever generated. Meanwhile
permalinks used "/:slug/", and :slug falls back to the title, so both files
claimed /hola-mundo/; Hugo wrote both documents into that one index.html.
Nothing failed. The pipeline was green throughout.
Each layer now refuses its part: post permalinks carry the year and month, the
CMS prefixes new filenames with the date, and translate.py aborts on a name
ending in a clash counter rather than quietly declining to translate it. The
build also runs with --printPathWarnings --panicOnWarning, so any future pair
of pages targeting one path fails the build instead of corrupting the output.
Existing post URLs change shape (/hola-mundo/ becomes /2026/09/hola-mundo/).
That costs nothing today, with one real post and no inbound links, and gets
expensive to change later.
Verified: 16/16 pipeline checks and 15/15 markdown checks still pass, the
clash-counter name aborts with the rename instruction, and an ordinary
filename still parses.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NizVpJ2dwzCbjCrTLCjeHn
67706ee36e