On 2020-08-14 at 18:59:53, Junio C Hamano wrote: > Junio C Hamano 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). Yeah, it wasn't intended that we munge mode bits, and I definitely agree we'd be better off distinguishing between all-zero and non-zero OIDs. As you might imagine, this is not my favorite test because have a large amount of diff formats, and even I think the giant list of sed expressions I wrote is hideous. It is, however, reasonably comprehensive, which is pretty much the only nice thing that can be said about it. > 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 $ZERO_OID > > - otherwise, repeat the character chosen in the first step as many > times as there are chars in the input. > > - regardless of all of the above, special case possible in-tree > blob modes (100644, 100755 and 120000) and don't munge them. > > I haven't tried it with the patch that started this discussion > thread, nor with SHA-256 build, though. This seems like a sane approach. > diff --git a/t/t4013-diff-various.sh b/t/t4013-diff-various.sh > index 43267d6024..b33e60ab9d 100755 > --- a/t/t4013-diff-various.sh > +++ b/t/t4013-diff-various.sh > @@ -130,27 +130,43 @@ test_expect_success setup ' > EOF > > process_diffs () { > - _x04="[0-9a-f][0-9a-f][0-9a-f][0-9a-f]" && > - _x07="$_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 () { > + s/($orx)/munge_oid($1)/ge; > + s/From ($x40)( |\))/"From " . munge_oid($1) . $2/ge; > + s/commit ($x40)($| \()/"commit " . munge_oid($1) . $2/ge; > + s/($x40) /munge_oid($1) . " "/ge; > + s/^($x40)($| )/munge_oid($1) . $2/e; > + s/($xab)(\.\.|,| |\.\.\.|$)/munge_oid($1) . $2/ge; > + print; > + } > + ' "$ZERO_OID" <"$1" > } This is much nicer, but I think we need the following on top of it because we have a couple of tricky cases the original didn't consider: * Some of our 64-bit object IDs get processed twice, turning them into 88-character object IDs, which don't match. We therefore need "\b". * The new unabbreviated index lines aren't accounted for, so I included them by possibly matching "\.\.". * We have some lines that look like "commit $OID (from $OID)" that aren't accounted for. Because we now have an optional OID in munge_oid, I had to account for that as well. So this is what's on top: diff --git a/t/t4013-diff-various.sh b/t/t4013-diff-various.sh index b5c7e1a63b..dfc87a0d19 100755 --- a/t/t4013-diff-various.sh +++ b/t/t4013-diff-various.sh @@ -140,6 +140,8 @@ process_diffs () { my ($oid) = @_; my $x; + return "" unless length $oid; + if ($oid =~ /^(100644|100755|120000)$/) { return $oid; } @@ -160,8 +162,8 @@ process_diffs () { while () { s/($orx)/munge_oid($1)/ge; s/From ($x40)( |\))/"From " . munge_oid($1) . $2/ge; - s/commit ($x40)($| \()/"commit " . munge_oid($1) . $2/ge; - s/($x40) /munge_oid($1) . " "/ge; + s/commit ($x40)($| \(from )($x40?)/"commit " . munge_oid($1) . $2 . munge_oid($3)/ge; + s/\b($x40)( |\.\.|$)/munge_oid($1) . $2/ge; s/^($x40)($| )/munge_oid($1) . $2/e; s/($xab)(\.\.|,| |\.\.\.|$)/munge_oid($1) . $2/ge; print; Or, a fresh original version: -- %< -- diff --git a/t/t4013-diff-various.sh b/t/t4013-diff-various.sh index e6eb4dd4c7..dfc87a0d19 100755 --- a/t/t4013-diff-various.sh +++ b/t/t4013-diff-various.sh @@ -130,27 +130,45 @@ test_expect_success setup ' EOF process_diffs () { - _x04="[0-9a-f][0-9a-f][0-9a-f][0-9a-f]" && - _x07="$_x05[0-9a-f][0-9a-f]" && - sed -e "s/$OID_REGEX/$ZERO_OID/g" \ - -e "s/From $_x40 /From $ZERO_OID /" \ - -e "s/from $_x40)/from $ZERO_OID)/" \ - -e "s/commit $_x40\$/commit $ZERO_OID/" \ - -e "s/commit $_x40 (/commit $ZERO_OID (/" \ - -e "s/$_x40 $_x40 $_x40/$ZERO_OID $ZERO_OID $ZERO_OID/" \ - -e "s/$_x40 $_x40 /$ZERO_OID $ZERO_OID /" \ - -e "s/^$_x40 $_x40$/$ZERO_OID $ZERO_OID/" \ - -e "s/^$_x40 /$ZERO_OID /" \ - -e "s/^$_x40$/$ZERO_OID/" \ - -e "s/$_x07\.\.$_x07/fffffff..fffffff/g" \ - -e "s/$_x07,$_x07\.\.$_x07/fffffff,fffffff..fffffff/g" \ - -e "s/$_x07 $_x07 $_x07/fffffff fffffff fffffff/g" \ - -e "s/$_x07 $_x07 /fffffff fffffff /g" \ - -e "s/Merge: $_x07 $_x07/Merge: fffffff fffffff/g" \ - -e "s/$_x07\.\.\./fffffff.../g" \ - -e "s/ $_x04\.\.\./ ffff.../g" \ - -e "s/ $_x04/ ffff/g" \ - "$1" + perl -e ' + my $oid_length = length($ARGV[0]); + my $x40 = "[0-9a-f]{40}"; + my $xab = "[0-9a-f]{4,16}"; + my $orx = "[0-9a-f]" x $oid_length; + + sub munge_oid { + my ($oid) = @_; + my $x; + + return "" unless length $oid; + + if ($oid =~ /^(100644|100755|120000)$/) { + return $oid; + } + + if ($oid =~ /^0*$/) { + $x = "0"; + } else { + $x = "f"; + } + + if (length($oid) == 40) { + return $x x $oid_length; + } else { + return $x x length($oid); + } + } + + while () { + s/($orx)/munge_oid($1)/ge; + s/From ($x40)( |\))/"From " . munge_oid($1) . $2/ge; + s/commit ($x40)($| \(from )($x40?)/"commit " . munge_oid($1) . $2 . munge_oid($3)/ge; + s/\b($x40)( |\.\.|$)/munge_oid($1) . $2/ge; + s/^($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') -- %< -- Anyone is welcome to have my sign-off if they pick up any part of this patch. -- brian m. carlson: Houston, Texas, US