Re: Merging bug (wrong conflicts)

[Karl Tomlinson]

Jacob Burckhardt wrote:
> 
> I saw different results than you.  You said no conflicts with older as
> common file, but I did get conflicts.  Maybe we used different
> commands?  My command was:
> 
> cat YOURS | diff3 -E -am MINE OLDER -
> 

> Below, I show one
> reasonable interpretation of the changes (although there are other
> reasonable interpretations).  Your original files did not have any
> blank lines in it, but I have added blanks lines so I can show what I
> think diff considers to be similar lines.  I made it so that similar
> liens are on the same horizontal level so it makes it it easy to make
> your eyes horizontally scan it.  Note that I run diff3 on your
> original files with no blank lines.  I only add blank lines here as a
> way to show how I think diff is matching things up:
> 
> R means result of merge.
> 
> M  O  Y  R
> v        v
> s  s  s  s
> x  x
> m1 m1 m1 m1
> m2 m2 m2 m2
> m1 m1
> x  x
> m2 m2
> s  s  s  s
> v  v  v  v
> s  s  s  s
>    x
>          <<<<<<< MINE
> m1 m1    m1
> x  x     x
> m2 m2    m2
>          =======
>          >>>>>>> -
> m1 m1 m1 m1
> m2 m2 m2 m2
> x  x
> s  s  s  s
> v        v

That layout makes things clear thanks.

> I think it did something reasonable.  Change M deleted 1 line with an
> "x" on it, and change Y deleted that same line plus the 3 lines just
> below.  Those 3 lines are shown contained in the conflict brackets.  I
> think it is not a burden to make a human manually look at that and
> decide what to do.  And there is a good chance that deleting all 4
> lines is not the right thing to do.  So therefore cvs should not just
> assume that is right.  As long as you pick the right section of the
> conflict, it will work.  Where as with some of my other test cases, the
> unpatched cvs has a conflict where there is obviously no conflict or
> it loses one person's changes with no hint to the user that it did so.
> 
> So to summarize, I think you patch makes cvs handle this case
> reasonably.  So far, I am satisfied with your patch the way it is.

Yes I agree it should be a conflict, and would be troubled if it wasn't.

> However, I am still worried that you and I get different results with
> the unpatched diff3.  Perhaps that indicates that I am not testing
> some case I *should* be testing.  So please let me know if I ran diff3
> wrong.

You did run diff3 correctly.

Sorry, I think I must've accidentally added that "x" that only exists
in O after I tested the files, because now I get the same results as you.

> 
> BTW, I have not yet tried out your other cases in your other e-mails.
> 

To check what I sent in 

http://www.mail-archive.com/bug-cvs%40gnu.org/msg00814.html

I copied from the web site and pasted into new files

for configuration 3)

> /usr/local/bin/diff3 -E -am MINE MINE YOURS
v
s
<<<<<<< MINE
x
m
=======
>>>>>>> YOURS
m
<<<<<<< MINE
x
x
x
x
x
x
x
x
x
x
=======
>>>>>>> YOURS
s
s
s
s
s
s
s
s
s
s
v

> cat YOURS | /usr/local/bin/diff3 -E -am MINE MINE - | diff YOURS -

gives no output as expected.

For configuration 2)

> /usr/local/bin/diff3 -E -am MINE OLDER YOURS
v
s
<<<<<<< MINE
x
m
=======
>>>>>>> YOURS
m
<<<<<<< MINE
x
=======
>>>>>>> YOURS
s
v
s
<<<<<<< MINE
x
=======
>>>>>>> YOURS
m
<<<<<<< MINE
m
x
=======
>>>>>>> YOURS
s
v

> cat YOURS | /usr/local/bin/diff3 -E -am MINE OLDER -
v
s
m
s
v
s
m
s
v

For configuration 1) of
http://www.mail-archive.com/bug-cvs%40gnu.org/msg00803.html

I'm not happy with

> /usr/local/bin/diff3 -E -am MINE OLDER YOURS | diff MINE -

having no output

M  O  Y  R=M

x  x  x  x
s  s  s  s
c  a  a  c
   b  b  
s  s  s  s
b     b  b
s     s  s
y  y  y  y

as it seems to easy to loose changes in Y.

I'm happier with

> cat YOURS | /usr/local/bin/diff3 -E -am MINE OLDER -
x
s
c
s
b
s
b
s
y

M  O  Y  R

x  x  x  x
s  s  s  s
c        c
s  a  a  s
b  b  b  b
s  s  s  s
      b  b
      s  s
y  y  y  y

and would even be happy with

M  O  Y  R

x  x  x  x
s  s  s  s
         <<<<<<< MINE
c        c
s  a  a  s
      b
      s
         =======
c        
s  a  a  a
      b  b
      s  s
         >>>>>>> YOURS
b  b  b  b
s  s  s  s
y  y  y  y