Re: [PATCH v2 2/2] doc hash-function-transition: pick SHA-256 as NewHash

On Fri, Aug 03, 2018 at 12:20:14AM -0700, Jonathan Nieder wrote:

Ævar Arnfjörð Bjarmason wrote:

quoted

 Object format
 ~~~~~~~~~~~~~
 The content as a byte sequence of a tag, commit, or tree object named
-by sha1 and newhash differ because an object named by newhash-name refers to
+by sha1 and sha256 differ because an object named by sha256-name refers to

Not about this patch: this should say SHA-1 and SHA-256, I think.
Leaving it as is in this patch as you did is the right thing.

[...]

quoted

@@ -255,10 +252,10 @@ network byte order):
   up to and not including the table of CRC32 values.
 - Zero or more NUL bytes.
 - The trailer consists of the following:
-  - A copy of the 20-byte NewHash checksum at the end of the
+  - A copy of the 20-byte SHA-256 checksum at the end of the

Not about this patch: a SHA-256 is 32 bytes.  Leaving that for a
separate patch as you did is the right thing, though.

[...]

quoted

-  - 20-byte NewHash checksum of all of the above.
+  - 20-byte SHA-256 checksum of all of the above.

Likewise.

For the record, my code for these does use 32 bytes.  I'm fine with this
being a separate patch, though.

[...]

quoted

@@ -351,12 +348,12 @@ the following steps:
    (This list only contains objects reachable from the "wants". If the
    pack from the server contained additional extraneous objects, then
    they will be discarded.)
-3. convert to newhash: open a new (newhash) packfile. Read the topologically
+3. convert to sha256: open a new (sha256) packfile. Read the topologically

Not about this patch: this one's more murky, since it's talking about
the object names instead of the hash function.  I guess "sha256"
instead of "SHA-256" for this could be right, but I worry it's going
to take time for me to figure out the exact distinction.  That seems
like a reason to just call it SHA-256 (but in a separate patch).

My assumption has been that when we are referring to the algorithm,
we'll use SHA-1 and SHA-256, and when we're referring to the input to
Git (in config files or in ^{sha256} notation), we use "sha1" and
"sha256".  I see this as analogous to "Git" and "git".

Otherwise, I'm fine with this document as it is.
-- 
brian m. carlson: Houston, Texas, US
OpenPGP: https://keybase.io/bk2204