git-merge-one-file.shon commit show-branch --reflog: add documentation. (abc8ab1)
   1#!/bin/sh
   2#
   3# Copyright (c) Linus Torvalds, 2005
   4#
   5# This is the git per-file merge script, called with
   6#
   7#   $1 - original file SHA1 (or empty)
   8#   $2 - file in branch1 SHA1 (or empty)
   9#   $3 - file in branch2 SHA1 (or empty)
  10#   $4 - pathname in repository
  11#   $5 - original file mode (or empty)
  12#   $6 - file in branch1 mode (or empty)
  13#   $7 - file in branch2 mode (or empty)
  14#
  15# Handle some trivial cases.. The _really_ trivial cases have
  16# been handled already by git-read-tree, but that one doesn't
  17# do any merges that might change the tree layout.
  18
  19case "${1:-.}${2:-.}${3:-.}" in
  20#
  21# Deleted in both or deleted in one and unchanged in the other
  22#
  23"$1.." | "$1.$1" | "$1$1.")
  24        if [ "$2" ]; then
  25                echo "Removing $4"
  26        else
  27                # read-tree checked that index matches HEAD already,
  28                # so we know we do not have this path tracked.
  29                # there may be an unrelated working tree file here,
  30                # which we should just leave unmolested.
  31                exit 0
  32        fi
  33        if test -f "$4"; then
  34                rm -f -- "$4" &&
  35                rmdir -p "$(expr "z$4" : 'z\(.*\)/')" 2>/dev/null || :
  36        fi &&
  37                exec git-update-index --remove -- "$4"
  38        ;;
  39
  40#
  41# Added in one.
  42#
  43".$2.")
  44        # the other side did not add and we added so there is nothing
  45        # to be done.
  46        ;;
  47"..$3")
  48        echo "Adding $4"
  49        test -f "$4" || {
  50                echo "ERROR: untracked $4 is overwritten by the merge."
  51                exit 1
  52        }
  53        git-update-index --add --cacheinfo "$6$7" "$2$3" "$4" &&
  54                exec git-checkout-index -u -f -- "$4"
  55        ;;
  56
  57#
  58# Added in both, identically (check for same permissions).
  59#
  60".$3$2")
  61        if [ "$6" != "$7" ]; then
  62                echo "ERROR: File $4 added identically in both branches,"
  63                echo "ERROR: but permissions conflict $6->$7."
  64                exit 1
  65        fi
  66        echo "Adding $4"
  67        git-update-index --add --cacheinfo "$6" "$2" "$4" &&
  68                exec git-checkout-index -u -f -- "$4"
  69        ;;
  70
  71#
  72# Modified in both, but differently.
  73#
  74"$1$2$3" | ".$2$3")
  75
  76        case ",$6,$7," in
  77        *,120000,*)
  78                echo "ERROR: $4: Not merging symbolic link changes."
  79                exit 1
  80                ;;
  81        esac
  82
  83        src2=`git-unpack-file $3`
  84        case "$1" in
  85        '')
  86                echo "Added $4 in both, but differently."
  87                # This extracts OUR file in $orig, and uses git-apply to
  88                # remove lines that are unique to ours.
  89                orig=`git-unpack-file $2`
  90                sz0=`wc -c <"$orig"`
  91                diff -u -La/$orig -Lb/$orig $orig $src2 | git-apply --no-add 
  92                sz1=`wc -c <"$orig"`
  93
  94                # If we do not have enough common material, it is not
  95                # worth trying two-file merge using common subsections.
  96                expr "$sz0" \< "$sz1" \* 2 >/dev/null || : >$orig
  97                ;;
  98        *)
  99                echo "Auto-merging $4"
 100                orig=`git-unpack-file $1`
 101                ;;
 102        esac
 103
 104        # Be careful for funny filename such as "-L" in "$4", which
 105        # would confuse "merge" greatly.
 106        src1=`git-unpack-file $2`
 107        git-merge-file "$src1" "$orig" "$src2"
 108        ret=$?
 109
 110        # Create the working tree file, using "our tree" version from the
 111        # index, and then store the result of the merge.
 112        git-checkout-index -f --stage=2 -- "$4" && cat "$src1" >"$4"
 113        rm -f -- "$orig" "$src1" "$src2"
 114
 115        if [ "$6" != "$7" ]; then
 116                echo "ERROR: Permissions conflict: $5->$6,$7."
 117                ret=1
 118        fi
 119        if [ "$1" = '' ]; then
 120                ret=1
 121        fi
 122
 123        if [ $ret -ne 0 ]; then
 124                echo "ERROR: Merge conflict in $4"
 125                exit 1
 126        fi
 127        exec git-update-index -- "$4"
 128        ;;
 129
 130*)
 131        echo "ERROR: $4: Not handling case $1 -> $2 -> $3"
 132        ;;
 133esac
 134exit 1