Re: [BUG] Cannot push some grafted branches

[Thomas Rast <trast@inf.ethz.ch>]

Johannes Sixt <j.sixt@viscovery.net> writes:

> Am 12/18/2012 12:00, schrieb Yann Dirson:
>> On Mon, 17 Dec 2012 13:14:56 -0800
>> Junio C Hamano <gitster@pobox.com> wrote:
>> 
>>> Andreas Schwab <schwab@linux-m68k.org> writes:
>>>
>>>> Christian Couder <christian.couder@gmail.com> writes:
>>>>
>>>>> Yeah, at one point I wanted to have a command that created to craft a
>>>>> new commit based on an existing one.
>>>>
>>>> This isn't hard to do, you only have to resort to plumbing:
>>>>
>>>> $ git cat-file commit fef11965da875c105c40f1a9550af1f5e34a6e62 |
>>>> sed
>>>> s/bfae342c973b0be3c9e99d3d86ed2e6b152b4a6b/790c83cda92f95f1b4b91e2ddc056a52a99a055d/
>>>> | git hash-object -t commit --stdin -w
>>>> bb45cc6356eac6c7fa432965090045306dab7026
>>>
>>> Good.  I do not think an extra special-purpose command is welcome
>>> here.
>> 
>> Well, I'm not sure this is intuitive enough to be useful to the average user :)
>
> When I played with git-replace in the past, I imagined that it could be
>
>    git replace <object> --commit ...commit options...
>
> that would do the trick.
>
> We could implement it with a git-replace--commit helper script that
> generates the replacement commit using the ...commit options... (to be
> defined what this should be), and git-replace would just pick its output
> (the SHA1 of the generated commit) as a substitute for the <replacement>
> argument that would have to be given without the --commit option.

I wouldn't even want a script -- we'd end up inventing a complicated
command-line editor for what can simply be done by judicious use of an
actual text editor.  How about something like the following?


 Documentation/git-replace.txt | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git i/Documentation/git-replace.txt w/Documentation/git-replace.txt
index 51131d0..2502118 100644
--- i/Documentation/git-replace.txt
+++ w/Documentation/git-replace.txt
@@ -61,6 +61,27 @@ OPTIONS
 	Typing "git replace" without arguments, also lists all replace
 	refs.
 
+
+EXAMPLE
+-------
+
+Replacements (and before them, grafts) are often used to replace the
+parent list of a commit.  Since commits are stored in a human-readable
+format, you can in fact change any property using the following
+recipe:
+
+------------------------------------------------
+$ git cat-file commit original_commit >tmp
+$ vi tmp
+------------------------------------------------
+In the editor, adjust the commit as needed.  For example, you can edit
+the parent lists by adding/removing lines starting with "parent".
+When done, replace the original commit with the edited one:
+------------------------------------------------
+$ git replace original_commit $(git hash-object -w tmp)
+------------------------------------------------
+
+
 BUGS
 ----
 Comparing blobs or trees that have been replaced with those that


-- 
Thomas Rast
trast@{inf,student}.ethz.ch