Often enough it happens that I get this warning and truly cannot remember what I may have changed, or whether I edited the footprint in the library (or don’t really know whether some of my colleagues changed the footprint in the library), whether it was a minor change such as the size of some text attribute, etc.
I am of course terrified (as I think one should be) to do “Update footprint” (though what I often do is that I save a copy of the layout file, then update footprints and compare / try to figure it out).
It would be great if the DRC dialog had an option (e.g., context menu) to ask KiCAD to “Show me the differences” when this warning/error appears — ideally, the difference should be shown in graphical mode, but in text mode could also work — e.g., a “diff” output, or a side-by-side view of the embedded vs. library copies.
Does that feature already exist and I am unaware of it? Or, is there a workaround that effectively accomplishes the same or nearly the same?
Not in the current version but in the nightly development version (8.99), a symbol and footprint diff feature is available within the ERC and DRC dialogue. There is a textural diff identifying what has changed and a layered visual diff tool where you can compare before and after by adjusting a slider.
EDIT
As this has been marked as the solution, it has been pointed out that this IS available in 8.0.
If you had a particularly annoying instance of this DRC error you could open the project in the Nightlies version and take advantage of this feature just to understand the issue . . . just don’t save your project.
Sure, that’s true! I’ve actually done this in the past, precisely related to DRC runs (IIRC, it was close to the release of version 6, where I had learned about the additional checks that v6 would offer, and wanted to take advantage of those)
It’s unfortunate that we’ll have to wait a year or two before we can fully enjoy that feature
Not sure if I have overlooked something but this is already available in v8 stable:
select a footprint–>mainmenu bar → Inspect–>Compare footprint with library.