On Mon, Mar 05, 2018 at 12:53:07PM -0800, Junio C Hamano wrote: > Jeff King <peff@xxxxxxxx> writes: > > > It's important that the diff-filter only filter the > > individual lines, and that there remain a one-to-one mapping > > between the input and output lines. Otherwise, things like > > hunk-splitting will behave quite unexpectedly (e.g., you > > think you are splitting at one point, but it has a different > > effect in the text patch we apply). > > > > We can't detect all problematic cases, but we can at least > > catch the obvious case where we don't even have the correct > > number of lines. > > Will queue. We could probably also make sure that each of the > corresponding line pair begins with the same '-/ /+' letter, but we > need to draw a line and stop somewhere, and I think the number of > lines is probably a good enough place. I think that would break things like diff-so-fancy, which actually removes the -/+ in favor of pure coloring (not something I care for myself, but it seems a legitimate use case). So it's probably best not to look at the content, not just from a "we can only go so far" perspective but also because we actively don't know what the filter's output is supposed to look like. -Peff
