output-map not working with external template

[hairyhenderson]

Discussed in #1676

^{Originally posted by dgarlitt March 15, 2023}
I was following the documentation here to learn how to use --output-map with external templates. I created the out.t file as indicated:

out.t

{{- /* .in may contain a directory name - we want to preserve that */ -}}
{{ $f := filepath.Base .in -}}
out/{{ .in | strings.ReplaceAll $f (index .filemap $f) }}.out

as well as the filemap.json file:

filemap.json

{ "eins.txt": "uno", "deux.txt": "dos" }

and stored my templates in the in directory. However, when I run the command in the example:

gomplate -t out=out.t -c filemap.json --input-dir=in --output-map='{{ template "out" }}'

I get the following error:

ERR  error="failed to gather templates for rendering: failed to render outputMap with ctx &map[ctx:0xc000a4e1b0 filemap:map[deux.txt:dos eins.txt:uno] in:deux.txt] and inPath deux.txt: failed to render template <OutputMap>: template: out:2:7: executing \"out\" at <.in>: nil data; no entry for key \"in\""

I am sure that I have a basic misunderstanding. Can someone please help point me in the right direction?

[hairyhenderson]

My response:

Hi @dgarlitt, thanks for reporting this - it looks like this is at least a bug in the documentation, and likely also a bug with how nested templates interact with output maps.

I tested this with various gomplate versions all the way back to v3.4.0 (when the output-map feature was added), and I get the same error too.

[thesuperzapper]

@hairyhenderson are you sure you did not just forget to provide the context to the template, that is:

• GOOD: --output-map='{{ template "out" . }}'
• BAD: --output-map='{{ template "out" }}'

[hairyhenderson]

😂 thanks so much @thesuperzapper - that's the issue!