git: correctly handle p1() on dirstate when underlying git repo is empty
This shows up in my next change, which ends up making an empty git
repo and then running hg.
Differential Revision: https://phab.mercurial-scm.org/D8271
#!/bin/sh
# Script to get stable diff output on any platform.
#
# Output of this script is almost equivalent to GNU diff with "-Nru".
#
# Use this script as "hg pdiff" via extdiff extension with preparation
# below in test scripts:
#
# $ cat >> $HGRCPATH <<EOF
# > [extdiff]
# > pdiff = sh "$RUNTESTDIR/pdiff"
# > EOF
filediff(){
# USAGE: filediff file1 file2 [header]
# compare with /dev/null if file doesn't exist (as "-N" option)
file1="$1"
if test ! -f "$file1"; then
file1=/dev/null
fi
file2="$2"
if test ! -f "$file2"; then
file2=/dev/null
fi
if cmp -s "$file1" "$file2" 2> /dev/null; then
# Return immediately, because comparison isn't needed. This
# also avoids redundant message of diff like "No differences
# encountered" (on Solaris)
return
fi
if test -n "$3"; then
# show header only in recursive case
echo "$3"
fi
# replace "/dev/null" by corresponded filename (as "-N" option)
diff -u "$file1" "$file2" |
sed "s@^--- /dev/null\(.*\)\$@--- $1\1@" |
sed "s@^\+\+\+ /dev/null\(.*\)\$@+++ $2\1@"
# in this case, files differ from each other
return 1
}
if test -d "$1" -o -d "$2"; then
# ensure comparison in dictionary order
(
if test -d "$1"; then (cd "$1" && find . -type f); fi
if test -d "$2"; then (cd "$2" && find . -type f); fi
) |
sed 's@^\./@@g' | sort | uniq |
while read file; do
filediff "$1/$file" "$2/$file" "diff -Nru $1/$file $2/$file"
done
# TODO: there is no portable way for current while-read based
# implementation to return 1 at detecting changes.
#
# On bash and dash, assignment to variable inside while-block
# doesn't affect outside, because inside while-block is executed
# in sub-shell. BTW, it affects outside while-block on ksh (as sh
# on Solaris).
else
filediff "$1" "$2"
fi