fix: Missing trailing newline when using both --multi and --string options

[Sam-C]

Problem

when using both --multi and --string options, the output does not have a trailing newline.

The output has trailing newline when

• using neither --multi or --string option
• using only --multi option
• using only --string option

Reproducible with:

$ jsonnet-v0.21.0 -e '{"outfile": "x"}' --multi . --string && cat outfile | xxd
00000000: 78                                       x

xxd shows that the outfile ends with 0x78 or the x character.

Expected:

$ jsonnet -e '{"output.json": "xxxxx"}' -m . -S && tail ms.json -c 1 | xxd
00000000: 780a                                     x.

xxd shows that the outfile ends with 0x0a which is the newline/line-feed (LF) character.

Closes #518

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[rudo-thomas]

Please note that this is a breaking change. And at least one other implementation copies the behaviour: databricks/sjsonnet

FWIW, cpp-jsonnet does output the newline.

Speaking as a heavy user of jsonnet and these flags, I'd welcome another flag that would turn the extra newline on and off.

[johnbartholomew]

Thanks for the contribution, this seems like a worthwhile improvement.

Please note that this is a breaking change.

Yeah, and it's kind of painful due to how long the discrepancy has existed. I'm seeking opinions on #518 (comment)

[johnbartholomew]

I've rebased this and will include it in #843.