Is there a way to configure vimdiff to ignore whitespace on lines that have a non-whitespace diff?
diff, vim, vimdiff
Solution
`diff` operates on lines, not characters or words, so `-b` and `-w` determine which lines to ignore. If a line is not ignored, which is the case whenever non-whitespace changes are involved (unless you ignore case or explicitly ignore lines matching some regex), `diff` will always output something like this:
1c1
< a,b,c,d
---
> a, b, c, e
Altering `diffopt` or even `diffexpr` only affects how Vim invokes `diff`, not how it then processes the diff it receives. Since neither `-b` nor `-w` will change the above diff, Vim will consequently display the same result. Thus what you're looking for is a way to change how exactly Vim highlights the diff it receives, which I don't believe is possible.
Problem
When diffing two files in vim (e.g. vim -d file1 file2), I want all whitespace to be ignored. I almost achieved this by following the advice of Adam Katz in this question: Is there a way to configure vimdiff to ignore ALL whitespaces? That advice causes the diff command to get the -w option, so that it doesn't include lines with only whitespace differences in the results. If there's a line with both whitespace differences and non-whitespaces differences, then these are correctly returned by diff. But vim highlights the whitespace as a difference too. E.g. If the two lines being diffed are: ``` File 1: a,b,c,d File 2: a, b, c, e ``` Then the highlighted diff will be `b, c, e` instead of my desired `e`. Is there any way to tell vim to ignore whitespace in its highlighting process? I'm using vim 7.3 (gvim).