Collision for lang-Variable when using specific language for pandoc-citeproc and Babel (Latex)

[esthet1cs]

It seems that both Babel and pandoc-citeproc use lang as a variable to set the language, but they don't use the same language codes, e.g. for german: ngerman (Babel) and de-DE (pandoc-citeproc), so when using Babel and pandoc-citeproc, setting another language throws an error either from Babel or from pandoc-citeproc.

What I'm trying to do: Generate a PDF from Markdown using two separate files (markdown + yaml)

pandoc -o test.pdf --csl my.csl --bibliography mybib.bib test.md test.yaml

The lang is defined in test.yaml. If I set lang: ngerman, pandoc-citeproc throws an error because it is looking for locales-ng.xml, which doesn't exist.
If I set lang: de-DE, Babel throws an error because it doesn't know that language.

Temporary Workaround

It seems, that pandoc-citeproc takes the first two letters of the lang variable and then looks for a file named locales-xx.xml, where xx are the first two letters of the lang variable, e.g. when defining lang: ngerman, pandoc-citeproc looks for locales-ng.xml.
Making a symbolic link from locales-ng.xml to locales-de-DE.xml did the trick. I haven't tried other languages, though.

[jgm]

Sorry, what pandoc version? In recent versions of pandoc, `lang` has been regularized, so de-DE should work, and pandoc will convert to 'ngerman' as needed for Babel output.

[esthet1cs]

Hi John, that's good news, thank you.
Sorry I didn't include this in my first post:

pandoc --version
pandoc 1.19.1
Compiled with pandoc-types 1.17.0.5, texmath 0.9.4.1, highlighting-kate 0.6.4

I'm using Debian Linux (Sid), pandoc 1.19.1 is the current up-to-date version in the Debian unstable repositories.

[esthet1cs]

Since this issue has already been resolved in recent versions of pandoc, I have moved it to the Debian bug tracking system: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=870248
Closing the issue here now.