From: Konstantin Khomoutov <kostix@bswap.ru>
Date: Thu, 27 Jul 2023 17:13:34 GMT
Subject: Re: [QUESTION] how to diff one blob with nothing
Message-ID: <20230727171334.6qg2xtecvmplg3or@carbon>
In-Reply-To: <CAOLTT8R84Zrtpd=j6o2V=Y_uD54XAS5EA7NWHsdfL+XCkD5cqA@mail.gmail.com>

>> If you haven't created one, of course it would fail.  It should help
>> to do
>>
>>     $ git hash-object -w --stdin </dev/null
>>
>> before running
>>
>>     $ git diff 00750edc e69de29bb
>>
>
> This is a viable solution, but it's a bit ugly since a read-only "diff"
> requires ”write“ an empty blob.

You could probably just do

  git cat-file -s e69de29bb

to figure out whether a blob is empty.

What is your end goal? Do you indeed want to produce a "trivial patch" which
merely "adds" all the lines of the blob you'd like to compare to an empty one
(assuming the blob conains text)?