From mboxrd@z Thu Jan  1 00:00:00 1970
From: Junio C Hamano <junkio@cox.net>
Subject: [RFH] xdiff shows trivially redundant diff.
Date: Sun, 02 Apr 2006 01:15:42 -0800
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Cc: Davide Libenzi <davidel@xmailserver.org>,
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$ git diff-tree -p 52e8a6^2 52d8a6 -- git-fetch.sh

shows a change that trivially is redundant, like this:

    diff --git a/git-fetch.sh b/git-fetch.sh
    index b4325d9..de4f011 100755
    --- a/git-fetch.sh
    +++ b/git-fetch.sh
    @@ -320,7 +320,7 @@ fetch_main () {
         ( : subshell because we muck with IFS
           IFS="    $LF"
           (
    -         git-fetch-pack $exec $keep "$remo...
    +         git-fetch-pack $exec $keep --thin...
           ) |
           while read sha1 remote_name
           do
    @@ -367,21 +367,26 @@ fetch_main "$reflist"

     # automated tag following
     case "$no_tags$tags" in
    -'')
    -       taglist=$(IFS=" " &&
    -       git-ls-remote $upload_pack --tags "$remote" |
    ...
    -       done)
    +'')
    +       case "$reflist" in
    +       *:refs/*)
    ...

Notice the first '-' and '+' lines of second hunk are identical?

There is another interesting thing.  This is running diff
between 52e8a6^2 and 52d8a6 blobs, but if I change them slightly
so that the first hunk is not different, then this anomaly
disappears.