logoalt Hacker News

LiamPowell • yesterday at 7:40 PM • 7 replies • view on HN

This has come up multiple times before [1], and more generally it's come up hundreds of times with Unix style tools in general. It's always been a stupid idea for every tool to have its own barely documented file format.

This wouldn't be an issue if patches were XML or JSON with a well defined schema, but everything must be a boutique undocumented format in the world of Unix tools.

Maybe the worst part about this is that it can entirely come from a patch being exported by git and then imported straight back in to git. If you can't even handle your own undocumented format then what hope do other tools have that want to work with it?

[1]: https://mas.to/@zekjur/116022397626943871

Replies

nyrikki • yesterday at 10:24 PM

While patch[0] has problems, the issue here is not that it is undocumented.

Git recently added this doc on roundtripping, and the problem is with git.

     Any line that is of the form:
     * three-dashes and end-of-line, or
     * a line that begins with "diff -", or
     * a line that begins with "Index: "

     is taken as the beginning of a patch, and the commit log message is terminated before the first occurrence of such a line.
The patch isn't even the complicated forms with RCS, ClearCase, Perforce, or SCCS support, it is just doing what the pre-POSIX spec says.

The argument is if git should do input sanitation etc...

But `patch -p1` is doing exactly what was documented, even in the original Larry Wall usenet post of the program.

[0] https://pubs.opengroup.org/onlinepubs/9799919799/utilities/p... [1] https://github.com/git/git/blob/94f057755b7941b321fd11fec1b2...

yjftsjthsd-h • yesterday at 7:46 PM

> This wouldn't be an issue if patches were XML or JSON with a well defined schema, but everything must be a boutique undocumented format in the world of Unix tools.

Patch files are readable by humans. Replacing them with XML or JSON would fix this problem, but at the expense of removing a core feature.

➕ show 1 reply
syntheticnature • yesterday at 7:47 PM

Haha, good one. Much like Makefiles, patch format precedes a lot of more modern things (by decades!) and is good enough to stick around. Unlike Makefiles, I've never seen tool gain any acceptance at all to replace patch.

➕ show 1 reply
chrishill89 • yesterday at 8:52 PM

> Maybe the worst part about this is that it can entirely come from a patch being exported by git and then imported straight back in to git.

No one wants to apply diffs in commit messages. But some people use this technique via email:

    Finally fix it

    ---

    Changes in v2:

    - Proper formatting
    - Remove irrelevant typo fix
They’ve used the `---` commit message delimiter in the commit message itself so that everything after it won’t be applied by git-am(1). So that’s intentional loss of round tripping.

I would personally use Git notes instead though.

    Finally fix it

    ---

    Notes:
        Changes in v2: ...
Avamander • yesterday at 9:52 PM

This is where I kind-of like the idea of PowerShell, it's just that I dislike almost all other aspects of it and around it.

➕ show 1 reply
kevin_thibedeau • yesterday at 8:51 PM

  Patch: 1985
  SGML: 1986
➕ show 1 reply
pwdisswordfishs • yesterday at 8:39 PM

> This wouldn't be an issue if patches were XML or JSON

Or MIME, even.