jd

Anyone here using semantic diffing tools in their daily work? How good are they? I use some for e.g. YAML [0] and JSON [1], and they're nice [2], but these are comparatively simple languages. I'm particularly curious because just plain diffing ASTs is more on the "syntax-aware diffing" side rather than the "semantic diffing" side, yet most semantic tooling descriptions stop at saying they use ASTs. ASTs are not necessarily in a minimal / optimized form by construction I believe, so I'm pretty sure you'll have situations where a "semantic" differ will report a difference, whereas a compiler would still compile the given translation unit to the same machine bytecode after all the optimization passes during later levels. Not even necessarily for target platform dependent reasons. But maybe this doesn't matter much or would be more confusing

> Would be nice to be able to use it as a VSCode extension! I've added support to use jd as a Git diff engine: https://github.com/josephburnett/jd?tab=readme-ov-file#use-g.... Can you configure VS Code use a custom command to show diffs?

> One feature I’ve yet to see is applying jq query syntax to the jsons before the diff Will you please add this as a feature request? https://github.com/josephburnett/jd/issues. I would like to hear more about how you would use it.

> When that happens, it computes a very long diff where it could have just said "element is missing at index N". That's exactly the problem addressed by this issue: https://github.com/josephburnett/jd/issues/50. And I've created a new v2 format to address this and other usecases. The v2 API will compute the longest common subsequence of two arrays and structure the diff around that (a standard way of producing a minimum diff). I've just released jd 1.9.1 with the `-v2` flag. Would you mind trying one of your use cases to see if the diff looks any better? I should say something exactly like that "@ (some path) - (some element)".

> I would note is that some restructurings with jq increased the quality of the diff by a lot. I would really like to know more about these restructurings. Would you mind dropping me an example here or at https://github.com/josephburnett/jd/issues please? There are somethings I won't do with jd (e.g. generic data transformations) but I do plan to add some more semantic aware metadata with the v2 API. Also, I'm glad this tool helped you! Made my day to here it :)

jd is a commandline utility and Go library for diffing and patching JSON and YAML values. It supports a native jd format (similar to unified format) as well as JSON Merge Patch (RFC 7386) and a subset of JSON Patch (RFC 6902). Try it out at http://play.jd-tool.io/.