mdiff: don't emit a diff header for empty trivial deltas
An empty trivial delta, coded as (0, 0, 0) makes the delta application
do nothing, but still takes 12 bytes, while skipping it altogether works
as much, without taking any space at all.
--- a/mercurial/mdiff.py Mon Jan 11 09:49:48 2016 -0800
+++ b/mercurial/mdiff.py Mon Jan 11 22:00:07 2016 -0500
@@ -376,7 +376,7 @@
return [(d[0], d[2], d[1] - d[0]) for d in bdiff.blocks(a, b)]
def trivialdiffheader(length):
- return struct.pack(">lll", 0, 0, length)
+ return struct.pack(">lll", 0, 0, length) if length else ''
def replacediffheader(oldlen, newlen):
return struct.pack(">lll", 0, oldlen, newlen)
--- a/tests/test-clonebundles.t Mon Jan 11 09:49:48 2016 -0800
+++ b/tests/test-clonebundles.t Mon Jan 11 22:00:07 2016 -0500
@@ -131,7 +131,7 @@
changes. If this output changes, we could break old clients.
$ f --size --hexdump partial.hg
- partial.hg: size=208
+ partial.hg: size=207
0000: 48 47 31 30 47 5a 78 9c 63 60 60 98 17 ac 12 93 |HG10GZx.c``.....|
0010: f0 ac a9 23 45 70 cb bf 0d 5f 59 4e 4a 7f 79 21 |...#Ep..._YNJ.y!|
0020: 9b cc 40 24 20 a0 d7 ce 2c d1 38 25 cd 24 25 d5 |..@$ ...,.8%.$%.|
@@ -143,8 +143,8 @@
0080: 41 d6 24 59 18 a4 a4 9a a6 18 1a 5b 98 9b 5a 98 |A.$Y.......[..Z.|
0090: 9a 18 26 9b a6 19 98 1a 99 99 26 a6 18 9a 98 24 |..&.......&....$|
00a0: 26 59 a6 25 5a 98 a5 18 a6 24 71 41 35 b1 43 dc |&Y.%Z....$qA5.C.|
- 00b0: 96 b0 83 f7 e9 45 8b d2 56 c7 a3 1f 82 52 d7 8a |.....E..V....R..|
- 00c0: 78 ed fc d5 76 f1 36 95 dc 05 07 00 ad 39 5e d3 |x...v.6......9^.|
+ 00b0: 16 b2 83 f7 e9 45 8b d2 56 c7 a3 1f 82 52 d7 8a |.....E..V....R..|
+ 00c0: 78 ed fc d5 76 f1 36 35 dc 05 00 36 ed 5e c7 |x...v.65...6.^.|
$ echo "http://localhost:$HGPORT1/partial.hg" > server/.hg/clonebundles.manifest
$ hg clone -U http://localhost:$HGPORT partial-bundle
@@ -189,11 +189,11 @@
by old clients.
$ f --size --hexdump full.hg
- full.hg: size=408
+ full.hg: size=406
0000: 48 47 32 30 00 00 00 0e 43 6f 6d 70 72 65 73 73 |HG20....Compress|
0010: 69 6f 6e 3d 47 5a 78 9c 63 60 60 90 e5 76 f6 70 |ion=GZx.c``..v.p|
0020: f4 73 77 75 0f f2 0f 0d 60 00 02 46 06 76 a6 b2 |.swu....`..F.v..|
- 0030: d4 a2 e2 cc fc 3c 03 23 06 06 e6 7d 40 b1 4d c1 |.....<.#...}@.M.|
+ 0030: d4 a2 e2 cc fc 3c 03 23 06 06 e6 65 40 b1 4d c1 |.....<.#...e@.M.|
0040: 2a 31 09 cf 9a 3a 52 04 b7 fc db f0 95 e5 a4 f4 |*1...:R.........|
0050: 97 17 b2 c9 0c 14 00 02 e6 d9 99 25 1a a7 a4 99 |...........%....|
0060: a4 a4 1a 5b 58 a4 19 27 9b a4 59 a4 1a 59 a4 99 |...[X..'..Y..Y..|
@@ -212,10 +212,10 @@
0130: 34 31 c5 d0 c4 24 31 c9 32 2d d1 c2 2c c5 30 25 |41...$1.2-..,.0%|
0140: 09 e4 ee 85 8f 85 ff 88 ab 89 36 c7 2a c4 47 34 |..........6.*.G4|
0150: fe f8 ec 7b 73 37 3f c3 24 62 1d 8d 4d 1d 9e 40 |...{s7?.$b..M..@|
- 0160: 06 3b 10 14 36 a4 38 10 04 d8 21 01 5a b2 83 f7 |.;..6.8...!.Z...|
+ 0160: 06 3b 10 14 36 a4 38 10 04 d8 21 01 9a b1 83 f7 |.;..6.8...!.....|
0170: e9 45 8b d2 56 c7 a3 1f 82 52 d7 8a 78 ed fc d5 |.E..V....R..x...|
- 0180: 76 f1 36 25 81 49 c0 ad 30 c0 0e 49 8f 54 b7 9e |v.6%.I..0..I.T..|
- 0190: d4 1c 09 00 bb 8d f0 bd |........|
+ 0180: 76 f1 36 25 81 89 c7 ad ec 90 34 48 75 2b 89 49 |v.6%......4Hu+.I|
+ 0190: bf 00 d6 97 f0 8d |......|
$ echo "http://localhost:$HGPORT1/full.hg" > server/.hg/clonebundles.manifest
$ hg clone -U http://localhost:$HGPORT full-bundle
--- a/tests/test-debugbundle.t Mon Jan 11 09:49:48 2016 -0800
+++ b/tests/test-debugbundle.t Mon Jan 11 22:00:07 2016 -0500
@@ -11,8 +11,8 @@
uncompressed size of bundle content:
332 (changelog)
282 (manifests)
- 105 b
- 105 c
+ 93 b
+ 93 c
Terse output:
@@ -34,9 +34,9 @@
ae25a31b30b3490a981e7b96a3238cc69583fda1 686dbf0aeca417636fa26a9121c681eabbb15a20 0000000000000000000000000000000000000000 991a3460af53952d10ec8a295d3d2cc2e5fa9690 686dbf0aeca417636fa26a9121c681eabbb15a20 55
b
- b80de5d138758541c5f05265ad144ab9fa86d1db 0000000000000000000000000000000000000000 0000000000000000000000000000000000000000 0e067c57feba1a5694ca4844f05588bb1bf82342 0000000000000000000000000000000000000000 12
+ b80de5d138758541c5f05265ad144ab9fa86d1db 0000000000000000000000000000000000000000 0000000000000000000000000000000000000000 0e067c57feba1a5694ca4844f05588bb1bf82342 0000000000000000000000000000000000000000 0
c
- b80de5d138758541c5f05265ad144ab9fa86d1db 0000000000000000000000000000000000000000 0000000000000000000000000000000000000000 991a3460af53952d10ec8a295d3d2cc2e5fa9690 0000000000000000000000000000000000000000 12
+ b80de5d138758541c5f05265ad144ab9fa86d1db 0000000000000000000000000000000000000000 0000000000000000000000000000000000000000 991a3460af53952d10ec8a295d3d2cc2e5fa9690 0000000000000000000000000000000000000000 0
$ cd ..