Re: [PATCH 2/3] hash-object doc: elaborate on -w and --literally promises

[Jeff King <peff@peff.net>]

On Mon, May 20, 2019 at 11:53:11PM +0200, Ævar Arnfjörð Bjarmason wrote:

> Clarify the hash-object docs to explicitly note that the --literally
> option guarantees that a loose object will be written, but that a
> normal -w ("write") invocation doesn't.

I had to double-check here: you mean that _when_ we are writing an
object, "--literally" would always write loose, right?

> At first I thought talking about "loose object" in the docs was a
> mistake in 83115ac4a8 ("git-hash-object.txt: document --literally
> option", 2015-05-04), but as is clear from 5ba9a93b39 ("hash-object:
> add --literally option", 2014-09-11) this was intended all along.

Hmm. After reading both of those, I do think it's mostly an
implementation detail. I would not be at all surprised to find that the
test suite relies on this (e.g., cleaning up with rm
.git/objects/ab/cd1234). But I suspect we also rely on that for the
non-literal case, too. ;)

So I am on the fence. In some sense it doesn't hurt to document the
behavior, but I'm not sure I would want to lock us in to any particular
behavior, even for --literally. The intent of the option (as I recall)
really is just "let us write whatever trash we want as an object,
ignoring all quality checks".

>  --literally::
> -	Allow `--stdin` to hash any garbage into a loose object which might not
> +	Allow for hashing arbitrary data which might not
>  	otherwise pass standard object parsing or git-fsck checks. Useful for
>  	stress-testing Git itself or reproducing characteristics of corrupt or
> -	bogus objects encountered in the wild.
> +	bogus objects encountered in the wild. When writing objects guarantees
> +	that the written object will be a loose object, for ease of debugging.

I had to read this last sentence a few times to parse it. Maybe a comma
before guarantees would help? Or even:

  When writing objects, this option guarantees that the written object
  will be a loose object, for ease of debugging.

-Peff