• geza42@alien.topB
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    1 year ago

    This has nothing to do with the diff program. Ediff is not able to highlight whitespace differences like it highlights non-whitespace differences. Maybe it is possible to do somehow, but by default, whitespace differences generate a diff region with no highlights (or as ediff calls it, refinements).

    It is because highlights are done on word level, and whitespaces are not words.

    • invsblduck@alien.topB
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      1 year ago

      Oh, interesting.
      I see.

      Just popped open the Ediff code and there is a significant amount of effort put into ignoring whitespace. Like, it’s not a shortcoming per se that it can’t show this content but rather a deliberate onslaught to avoid it at all costs. The author must have been really annoyed by whitespace. 😂

      I mostly use (ediff-buffers) in my day-to-day work in Spacemacs to compare two regions that I’ve narrowed to indirect buffers, and, interestingly, it does show me diffs that contain whitespace-only changes and prints the following to the echo area:

      https://preview.redd.it/587vplu76e1c1.png?width=1896&format=png&auto=webp&s=e3d559ae695972f62865560b96f23953b4b26027

      I did a quick test with other ediff functions bound in Spacemacs, and ediff-windows-linewise has the same behavior, but ediff-windows-wordwise does not -- it completely ignored diffs that were whitespace only and there was not even ## binding available in that ediff session.

      When browsing the code, I found a local variable named ediff-whitespace (which u/doolio_ has already pointed out here in reply to you, actually), which is curious:

      (defvar-local ediff-whitespace " \n\t\f\r\240"
        "Characters constituting white space.
      These characters are ignored when differing regions are split into words.")
      

      (\240 is Unicode symbol for nonbreakable whitespace.)

      I wonder whether this variable can be set to nil.

      PS:

      It is because highlights are done on word level, and whitespaces are not words.

      Apparently word splitting is configurable with ediff-forward-word-function ?