Re: [PATCH 2/2] annotate: Fix bug when parsing merges with differing real and logical parents.

This does stop it from dying on Jeff King's bug report (<20060803203848.GA15121@coredump.intra.peff.net>) to annotate builtin-read-tree.c. However,...

Comparing output between "annotate" and "blame -c" on the same file shows a rather interesting differences.

(1) "annotate" blames the first line "/*" to d147e501 made on
    2006-05-23, while "blame" annotates it with 8bc9a0c7 made on
    2005-04-07.  As far as I remember this line has never been
    touched by anybody during the life of the file, so the
    latter sounds more plausible.

(2) The 13th line to #include "cache-tree.h" is blamed on
    3f69d405 by "annotate", while annotation by "blame" reads
    that it came from bad68ec9.

    3f69d405 is a merge to incorporate the line into "master"
    branch.  "git show -M 3f69d405 -- builtin-read-tree.c read-tree.c"
    starts with:

        diff --cc builtin-read-tree.c
        index ec40d01,99e7c75..716f792
        --- a/builtin-read-tree.c
        +++ b/builtin-read-tree.c
        @@@ -9,9 -9,9 +9,10 @@@

          #include "object.h"
          #include "tree.h"
        + #include "cache-tree.h"
	  #include <sys/time.h>

    Which means the line is new from the point of view of the
    "master" branch, but existed in the branch that this commit
    merges from (namely, jc/cache-tree) already.

    "git show -M bad68ec9 -- read-tree.c" shows that it is the
    one that added the #include line to the history.

(3) The 14th line to #include <sys/time.h> is blamed on d147e501
    by "annotate" but "blame" says it came from 744633cb.  It is
    obvious the latter is correct, if you look at "git show" on
    these commits.  The eye-candy was what made <sys/time.h>
    necessary (it needed to do the progress-signal stuff).

In fact, "annotate" attributes too many lines to d147e501 (839 lines).

Given that "git show -M d147e501 -- read-tree.c builtin-read-tree.c" shows only 2 insertions and 1 deletion, it does not sound right. The commit adds #include "builtin.h" and changes the function name "main" to "cmd_read_tree".

On the other hand, "blame" attributes only 1 line to this commit; the line to #include "builtin.h". The other change this commit introduces (main -> cmd_read_tree) is not counted because the third parameter to the function changes after this commit by a91af794 (which, by the way, both "annotate" and "blame" get right), and the line this commit introduces did not survive.