On 04/15/2013 08:15 PM, Junio C Hamano wrote:
> Thomas Ackermann <th.acker@xxxxxxxx> writes:
>
>> Use "SHA-1" instead of "SHA1" whenever we talk about the hash function.
>> When used as a programming symbol, we keep "SHA1".
>>
>> Signed-off-by: Thomas Ackermann <th.acker@xxxxxxxx>
>> ---
>
> Thanks. Will queue as-is for now, but I wonder if we want to fix
> them to more official "object name", if we are going to the trouble
> of fixing all of these. It depends on how many places already
> correctly spell SHA-1, I guess.
I like the idea of making the Git documentation (and the source code)
more algorithm-agnostic. But personally, I think "object name" is a bad
generic term for describing object hashes. The word "name" suggests a
moniker that was intentionally given to the object. I suppose that this
is a big reason that the term "SHA-1" is used so frequently rather than
"object name"--because it is transparently obvious that an "SHA-1" is a
hash as opposed to, say, a filename.
In my opinion, rather than expand the use of the term "object name", we
should pick a better official term that makes it more obvious what we
are talking about, like "object hash".
While we are at it, if being more algorithm-agnostic is considered a
worthy goal, maybe it would be helpful to establish a source code naming
convention to be used in new code in favor of "sha1"; for example,
ohash = hash of an object of unknown type
chash = hash of a commit object
etc.
Obviously I'm not suggesting that Git should transition away from using
SHA-1s, just that the choice of hashing algorithm need not be quite so
explicit in source code that doesn't really need to care.
On a related topic, I find it shocking how often the hard-coded
constants "20", "40", and "41" appear in git source code:
$ git grep -e '\<20\>' -- '*.c' '*.h' '*.sh' '*.perl' | wc -l
689
$ git grep -e '\<4[01]\>' -- '*.c' '*.h' '*.sh' '*.perl' | wc -l
339
The vast majority of these have to do with the length of a SHA-1 hash.
I think it would aid source-code readability if there were named
constants for the lengths of object hashes in binary and hex format.
Michael
--
Michael Haggerty
mhagger@xxxxxxxxxxxx
http://softwareswirl.blogspot.com/
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