[PATCH 5 of 5 rfc] bdiff: make sure we append to repeated lines instead of inserting into range

[Mads Kiilerich]

# HG changeset patch
# User Mads Kiilerich <madski at unity3d.com>
# Date 1478208837 -3600
#      Thu Nov 03 22:33:57 2016 +0100
# Node ID be83c5f4ec8931cb7e771a80a3ef5e2042a005c1
# Parent  3e0216b2a0995cb21946bc13fb21391013332c57
bdiff: make sure we append to repeated lines instead of inserting into range

This will mitigate the symptoms that tests exposed in the previous changeset.

Arguably, we need similar handling for longer sequences of repeated lines...

But also, we already have examples of how the heuristics handle other cases in
a similar way.

diff --git a/mercurial/bdiff.c b/mercurial/bdiff.c
--- a/mercurial/bdiff.c
+++ b/mercurial/bdiff.c
@@ -187,7 +187,7 @@ static int longest_match(struct bdiff_li
 				} else if (i == mi && findbetterb) {
 					/* better j in first upper half */
 					mj = j;
-					if (j <= bhalf)
+					if (j <= bhalf && !(j > 0 && k == 1 && b[j - 1].e == b[j].e))
 						findbetterb = 0;
 				}
 			}
diff --git a/tests/test-annotate.t b/tests/test-annotate.t
--- a/tests/test-annotate.t
+++ b/tests/test-annotate.t
@@ -91,8 +91,8 @@ annotate (JSON)
 annotate -n b
 
   $ hg annotate -n b
+  0: a
   1: a
-  0: a
   1: a
   3: b4
   3: b5
@@ -111,8 +111,8 @@ annotate --no-follow b
 annotate -nl b
 
   $ hg annotate -nl b
-  1:1: a
   0:1: a
+  1:2: a
   1:3: a
   3:4: b4
   3:5: b5
@@ -121,8 +121,8 @@ annotate -nl b
 annotate -nf b
 
   $ hg annotate -nf b
+  0 a: a
   1 a: a
-  0 a: a
   1 a: a
   3 b: b4
   3 b: b5
@@ -131,8 +131,8 @@ annotate -nf b
 annotate -nlf b
 
   $ hg annotate -nlf b
-  1 a:1: a
   0 a:1: a
+  1 a:2: a
   1 a:3: a
   3 b:4: b4
   3 b:5: b5
@@ -156,8 +156,8 @@ annotate -nlf b
 annotate after merge
 
   $ hg annotate -nf b
+  0 a: a
   1 a: a
-  0 a: a
   1 a: a
   3 b: b4
   4 b: c
@@ -166,8 +166,8 @@ annotate after merge
 annotate after merge with -l
 
   $ hg annotate -nlf b
-  1 a:1: a
   0 a:1: a
+  1 a:2: a
   1 a:3: a
   3 b:4: b4
   4 b:5: c
@@ -198,7 +198,7 @@ annotate after merge with -l
 annotate after rename merge
 
   $ hg annotate -nf b
-  1 a: a
+  0 a: a
   6 b: z
   1 a: a
   3 b: b4
@@ -209,7 +209,7 @@ annotate after rename merge
 annotate after rename merge with -l
 
   $ hg annotate -nlf b
-  1 a:1: a
+  0 a:1: a
   6 b:2: z
   1 a:3: a
   3 b:4: b4
@@ -226,7 +226,7 @@ Issue2807: alignment of line numbers wit
   $ echo more >> b
   $ hg ci -mmore -d '7 0'
   $ hg annotate -nlf b
-   1 a: 1: a
+   0 a: 1: a
    6 b: 2: z
    1 a: 3: a
    3 b: 4: b4
@@ -240,15 +240,15 @@ Issue2807: alignment of line numbers wit
 linkrev vs rev
 
   $ hg annotate -r tip -n a
+  0: a
   1: a
-  0: a
   1: a
 
 linkrev vs rev with -l
 
   $ hg annotate -r tip -nl a
-  1:1: a
   0:1: a
+  1:2: a
   1:3: a
 
 Issue589: "undelete" sequence leads to crash
diff --git a/tests/test-bhalf.t b/tests/test-bhalf.t
--- a/tests/test-bhalf.t
+++ b/tests/test-bhalf.t
@@ -105,8 +105,8 @@ Explore some bdiff implementation edge c
   --- a/x
   +++ b/x
   @@ -1,1 +1,3 @@
+   a
   +a
-   a
   +a
   diff --git a/y b/y
   --- a/y
diff --git a/tests/test-commit-amend.t b/tests/test-commit-amend.t
--- a/tests/test-commit-amend.t
+++ b/tests/test-commit-amend.t
@@ -47,8 +47,8 @@ Amending changeset with changes in worki
   --- a/a	Thu Jan 01 00:00:00 1970 +0000
   +++ b/a	Thu Jan 01 00:00:00 1970 +0000
   @@ -1,1 +1,3 @@
+   a
   +a
-   a
   +a
   $ hg log
   changeset:   1:43f1ba15f28a
@@ -122,13 +122,13 @@ No changes, just a different message:
   uncompressed size of bundle content:
        254 (changelog)
        163 (manifests)
-       141  a
+       129  a
   saved backup bundle to $TESTTMP/.hg/strip-backup/74609c7f506e-1bfde511-amend-backup.hg (glob)
   1 changesets found
   uncompressed size of bundle content:
        250 (changelog)
        163 (manifests)
-       141  a
+       129  a
   adding branch
   adding changesets
   adding manifests
@@ -140,8 +140,8 @@ No changes, just a different message:
   --- a/a	Thu Jan 01 00:00:00 1970 +0000
   +++ b/a	Thu Jan 01 00:00:00 1970 +0000
   @@ -1,1 +1,3 @@
+   a
   +a
-   a
   +a
   $ hg log
   changeset:   1:1cd866679df8
@@ -266,13 +266,13 @@ then, test editing custom commit message
   uncompressed size of bundle content:
        249 (changelog)
        163 (manifests)
-       143  a
+       131  a
   saved backup bundle to $TESTTMP/.hg/strip-backup/5f357c7560ab-e7c84ade-amend-backup.hg (glob)
   1 changesets found
   uncompressed size of bundle content:
        257 (changelog)
        163 (manifests)
-       143  a
+       131  a
   adding branch
   adding changesets
   adding manifests
@@ -309,13 +309,13 @@ Same, but with changes in working dir (d
   uncompressed size of bundle content:
        464 (changelog)
        322 (manifests)
-       261  a
+       249  a
   saved backup bundle to $TESTTMP/.hg/strip-backup/7ab3bf440b54-8e3b5088-amend-backup.hg (glob)
   1 changesets found
   uncompressed size of bundle content:
        257 (changelog)
        163 (manifests)
-       145  a
+       133  a
   adding branch
   adding changesets
   adding manifests