discovery: drop findoutgoing and simplify findcommonincoming's api
This is a long desired cleanup and paves the way for new discovery.
To specify subsets for bundling changes, all code should use the heads
of the desired subset ("heads") and the heads of the common subset
("common") to be excluded from the bundled set. These can be used
revlog.findmissing instead of revlog.nodesbetween.
This fixes an actual bug exposed by the change in test-bundle-r.t
where we try to bundle a changeset while specifying that said changeset
is to be assumed already present in the target. This used to still
bundle the changeset. It no longer does. This is similar to the bugs
fixed by the recent switch to heads/common for incoming/pull.
$ hg init repo
$ cd repo
$ cat > a <<EOF
> c
> c
> a
> a
> b
> a
> a
> c
> c
> EOF
$ hg ci -Am adda
adding a
$ cat > a <<EOF
> c
> c
> a
> a
> dd
> a
> a
> c
> c
> EOF
default context
$ hg diff --nodates
diff -r cf9f4ba66af2 a
--- a/a
+++ b/a
@@ -2,7 +2,7 @@
c
a
a
-b
+dd
a
a
c
invalid --unified
$ hg diff --nodates -U foo
abort: diff context lines count must be an integer, not 'foo'
[255]
$ hg diff --nodates -U 2
diff -r cf9f4ba66af2 a
--- a/a
+++ b/a
@@ -3,5 +3,5 @@
a
a
-b
+dd
a
a
$ hg --config diff.unified=2 diff --nodates
diff -r cf9f4ba66af2 a
--- a/a
+++ b/a
@@ -3,5 +3,5 @@
a
a
-b
+dd
a
a
$ hg diff --nodates -U 1
diff -r cf9f4ba66af2 a
--- a/a
+++ b/a
@@ -4,3 +4,3 @@
a
-b
+dd
a
invalid diff.unified
$ hg --config diff.unified=foo diff --nodates
abort: diff context lines count must be an integer, not 'foo'
[255]
test off-by-one error with diff -p
$ hg init diffp
$ cd diffp
$ echo a > a
$ hg ci -Ama
adding a
$ rm a
$ echo b > a
$ echo a >> a
$ echo c >> a
$ hg diff -U0 -p --nodates
diff -r cb9a9f314b8b a
--- a/a
+++ b/a
@@ -1,0 +1,1 @@
+b
@@ -2,0 +3,1 @@ a
+c