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Re: [PATCH v3 07/11] Documentation/replace: tell that -f option bypasses the type check

From
Philip Oakley <philipoakley@iee.org>
Date
Sep 2, 2013, 21:50 UTC
Message-ID
<66A16BF0137D40568A34C316DDA6D32E@PhilipOakley>
In-Reply-To
<20130902.081157.986549849748779440.chriscool@tuxfamily.org>
From: "Christian Couder" <chriscool@tuxfamily.org>
Show 48 quoted lines
> From: "Philip Oakley" <philipoakley@iee.org>
>>
>> From: "Christian Couder" <chriscool@tuxfamily.org>
>>
>>> Maybe we can show that in an example. But I think the patch is quite
>>> clear as it is and should be enough.
>>>
>>> If we really want to correct some false beliefs, the best would be 
>>> to
>>> state the truth where those false beliefs are stated.
>>>
>> I've added a sub-comment to the original SO post that started this
>> thread (my post $gmane/231598 - SO/a/18027030/717355), but given the
>> guy's blog has comments going back to 2009 I suspect its a bit of a
>> http://xkcd.com/386/ task, hence my desire that it's explicitly
>> mentioned in the 'replace' documentation. In addition, if the guy
>> doesn't correct his post I'll mark it down in a couple of days to 
>> make
>> it plain to other readers it's in error.
>>
>> The creation of a (merge?) commit that's equivalent to a graft line
>> isn't something that jumps out (to me) as an easy couple lines of 
>> bash
>> script.
>>
>> A 'graft2replace' script (or 'git-graft' command) which takes an
>> existing graft file (or command line list) and creates the 
>> replacement
>> objects and then does the replace, all while still in a dirty tree
>> would be the holy grail for properly deprecating grafts (which are
>> sooo easy to create)
>
> You mean something like the following:
>
> $ cat  ./graft2replace.sh
> #!/bin/bash
>
> while read orig parents
> do
>        printf "%s" "git cat-file commit $orig"
>        printf "%s" " | perl -n -e 'print unless /^parent /'"
>        insn=''
>        for commit in $parents; do insn="$insn print \"parent 
> $commit\\n\";"; done
>        printf "%s" " | perl -n -e 'print; if (/^tree /) { $insn }'"
>        printf "%s\n" " > new_commit.txt"
>        printf "%s\n" 'REPL=$(git hash-object -t commit -w 
> new_commit.txt)'
Does `hash-object` do the inverese of `cat-file commit`?

I didn't find the hash-object(1) man page very informative on that matter and a (very) quick look at its code made me think it was just hashing the raw contents which wouldn't be what what was wanted.

Show 32 quoted lines
>        printf "%s\n" "git replace $orig \$REPL"
> done
>
> This generates shell instructions from a graft file. Then you only 
> need to execute the generated shell instructions.
> For example:
>
> $ cat graft_file.txt
> 5bf34fff3186254d7254583675d10ddf98df989b 
> 79fe155489351e8af829a3106e7150397c57d863 
> dcfbab6bea3df3166503f3084cec2679f10f9e80
> fb5657082148297b61fbca7e64d51c1e7870309a
>
> $ cat graft_file.txt | ./graft2replace.sh
> git cat-file commit 5bf34fff3186254d7254583675d10ddf98df989b | 
> perl -n -e 'print unless /^parent /' | perl -n -e 'print; if (/^tree 
> /) {  print "parent 79fe155489351e8af829a3106e7150397c57d863\n"; print 
> "parent dcfbab6bea3df3166503f3084cec2679f10f9e80\n"; }' > 
> new_commit.txt
> REPL=$(git hash-object -t commit -w new_commit.txt)
> git replace 5bf34fff3186254d7254583675d10ddf98df989b $REPL
> git cat-file commit fb5657082148297b61fbca7e64d51c1e7870309a | 
> perl -n -e 'print unless /^parent /' | perl -n -e 'print; if (/^tree 
> /) {  }' > new_commit.txt
> REPL=$(git hash-object -t commit -w new_commit.txt)
> git replace fb5657082148297b61fbca7e64d51c1e7870309a $REPL
>
> Note that I haven't really tested it.
>
> Best,
> Christian.
> --

I think we could call it 'git-graft', being the help function/script that converts raw grafts to proper object replacements ;-)

Philip 
Previous: Christian CouderNext: Jonathan Nieder
Message 18 of 33 in “Check replacement object type and minor updates”
  1. 00/11 Check replacement object type and minor updatesChristian Couder, Aug 31, 2013
  2. 01/11 replace: forbid replacing an object with one of a different typeChristian Couder, Aug 31, 2013
  3. Philip OakleyAug 31, 2013
  4. Christian CouderSep 1, 2013
  5. Philip OakleySep 1, 2013
  6. 02/11 Documentation/replace: state that objects must be of the same typeChristian Couder, Aug 31, 2013
  7. 03/11 t6050-replace: test that objects are of the same typeChristian Couder, Aug 31, 2013
  8. 04/11 t6050-replace: add test to clean up all the replace refsChristian Couder, Aug 31, 2013
  9. 05/11 Documentation/replace: add Creating Replacement Objects sectionChristian Couder, Aug 31, 2013
  10. Philip OakleyAug 31, 2013
  11. Christian CouderSep 1, 2013
  12. 06/11 replace: bypass the type check if -f option is usedChristian Couder, Aug 31, 2013
  13. 07/11 Documentation/replace: tell that -f option bypasses the type checkChristian Couder, Aug 31, 2013
  14. Philip OakleyAug 31, 2013
  15. Christian CouderSep 1, 2013
  16. Philip OakleySep 1, 2013
  17. Christian CouderSep 2, 2013
  18. Philip OakleySep 2, 2013
  19. Jonathan NiederSep 2, 2013
  20. Philip OakleySep 2, 2013
  21. Jonathan NiederSep 2, 2013
  22. Philip OakleySep 2, 2013
  23. Christian CouderSep 3, 2013
  24. 08/11 t6050-replace: check that -f option bypasses the type checkChristian Couder, Aug 31, 2013
  25. Eric SunshineSep 1, 2013
  26. Christian CouderSep 1, 2013
  27. 09/11 replace: allow long option namesChristian Couder, Aug 31, 2013
  28. 10/11 Documentation/replace: list long option namesChristian Couder, Aug 31, 2013
  29. 11/11 t6050-replace: use some long option namesChristian Couder, Aug 31, 2013
  30. Philip OakleyAug 31, 2013
  31. Christian CouderSep 1, 2013
  32. Eric SunshineSep 1, 2013
  33. Christian CouderSep 1, 2013

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