Junio C Hamano <gitster@xxxxxxxxx> writes:
> Ouch. These apparently come from
>
> process_diffs () {
> ...
> }
>
> Hash-independence may be good, but it should not munge expected mode
> bits from 100644 to ffff44, which I think is a bug in the original
> introduced in 72f936b1 (t4013: make test hash independent,
> 2020-02-07).
>
> When we are adjusting the abbrev length of the index line, of course
> $_x07 would not be sufficient to match the abbreviated object name
> in full, so a79 vs 895 can be explained and is a bug in this patch
> that did not update the process_diffs helper.
>
> Another thing that I find somewhat problematic in the original
> (brian cc'ed) is that it does not special case all-zero object name
> specially. By turning any and all instances of $_x40 to $ZERO_OID,
> we lose the distinction between a random-looking object name which
> got turned into $ZERO_OID by the processing, and an object name that
> was $ZERO_OID from the beginning, so we won't catch a possible
> future bug where new file's preimage object name is not $ZERO_OID
> (this is plausible when you try to show an intent-to-add entry; the
> diff between the index and the working tree would be "new file"
> patch, but the index entry records the object name for an empty
> blob, e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 instead of $ZERO_OID
> can easily be emitted by a mistaken implementation).
So here is what I came up with as a possible starting point. The
idea is to grab hexadecimal strings at locations the original tried
to isolate with various contexts, and
- if the input happens to be all zero, use '0', otherwise use 'f'
- if the input is 40-bytes (i.e. unabbreviated object name in the
SHA-1 world), repeat the character chosen in the first step as
many times as there are chars in $ZERO_OID
- otherwise, repeat the character chosen in the first step as many
times as there are chars in the input.
- regardless of all of the above, special case possible in-tree
blob modes (100644, 100755 and 120000) and don't munge them.
I haven't tried it with the patch that started this discussion
thread, nor with SHA-256 build, though.
t/t4013-diff-various.sh | 58 +++++++++++++++++++++++++++++++------------------
1 file changed, 37 insertions(+), 21 deletions(-)
diff --git a/t/t4013-diff-various.sh b/t/t4013-diff-various.sh
index 43267d6024..b33e60ab9d 100755
--- a/t/t4013-diff-various.sh
+++ b/t/t4013-diff-various.sh
@@ -130,27 +130,43 @@ test_expect_success setup '
EOF
process_diffs () {
- _x04="[0-9a-f][0-9a-f][0-9a-f][0-9a-f]" &&
- _x07="$_x05[0-9a-f][0-9a-f]" &&
- sed -e "s/$OID_REGEX/$ZERO_OID/g" \
- -e "s/From $_x40 /From $ZERO_OID /" \
- -e "s/from $_x40)/from $ZERO_OID)/" \
- -e "s/commit $_x40\$/commit $ZERO_OID/" \
- -e "s/commit $_x40 (/commit $ZERO_OID (/" \
- -e "s/$_x40 $_x40 $_x40/$ZERO_OID $ZERO_OID $ZERO_OID/" \
- -e "s/$_x40 $_x40 /$ZERO_OID $ZERO_OID /" \
- -e "s/^$_x40 $_x40$/$ZERO_OID $ZERO_OID/" \
- -e "s/^$_x40 /$ZERO_OID /" \
- -e "s/^$_x40$/$ZERO_OID/" \
- -e "s/$_x07\.\.$_x07/fffffff..fffffff/g" \
- -e "s/$_x07,$_x07\.\.$_x07/fffffff,fffffff..fffffff/g" \
- -e "s/$_x07 $_x07 $_x07/fffffff fffffff fffffff/g" \
- -e "s/$_x07 $_x07 /fffffff fffffff /g" \
- -e "s/Merge: $_x07 $_x07/Merge: fffffff fffffff/g" \
- -e "s/$_x07\.\.\./fffffff.../g" \
- -e "s/ $_x04\.\.\./ ffff.../g" \
- -e "s/ $_x04/ ffff/g" \
- "$1"
+ perl -e '
+ my $oid_length = length($ARGV[0]);
+ my $x40 = "[0-9a-f]{40}";
+ my $xab = "[0-9a-f]{4,16}";
+ my $orx = "[0-9a-f]" x $oid_length;
+
+ sub munge_oid {
+ my ($oid) = @_;
+ my $x;
+
+ if ($oid =~ /^(100644|100755|120000)$/) {
+ return $oid;
+ }
+
+ if ($oid =~ /^0*$/) {
+ $x = "0";
+ } else {
+ $x = "f";
+ }
+
+ if (length($oid) == 40) {
+ return $x x $oid_length;
+ } else {
+ return $x x length($oid);
+ }
+ }
+
+ while (<STDIN>) {
+ s/($orx)/munge_oid($1)/ge;
+ s/From ($x40)( |\))/"From " . munge_oid($1) . $2/ge;
+ s/commit ($x40)($| \()/"commit " . munge_oid($1) . $2/ge;
+ s/($x40) /munge_oid($1) . " "/ge;
+ s/^($x40)($| )/munge_oid($1) . $2/e;
+ s/($xab)(\.\.|,| |\.\.\.|$)/munge_oid($1) . $2/ge;
+ print;
+ }
+ ' "$ZERO_OID" <"$1"
}
V=$(git version | sed -e 's/^git version //' -e 's/\./\\./g')
