revlog: calculate base revisions iteratively
This is in preparation for generaldelta, where the revlog entry base field is
reinterpreted as the deltaparent. For that reason we also rename the base
function to chainbase.
Without generaldelta, performance is unaffected, but generaldelta will suffer
from this in _addrevision, since delta chains will be walked repeatedly.
A cache has been added to eliminate this problem completely.
Testing diff --change
$ hg init a
$ cd a
$ echo "first" > file.txt
$ hg add file.txt
$ hg commit -m 'first commit' # 0
$ echo "second" > file.txt
$ hg commit -m 'second commit' # 1
$ echo "third" > file.txt
$ hg commit -m 'third commit' # 2
$ hg diff --nodates --change 1
diff -r 4bb65dda5db4 -r e9b286083166 file.txt
--- a/file.txt
+++ b/file.txt
@@ -1,1 +1,1 @@
-first
+second
$ hg diff --change e9b286083166
diff -r 4bb65dda5db4 -r e9b286083166 file.txt
--- a/file.txt Thu Jan 01 00:00:00 1970 +0000
+++ b/file.txt Thu Jan 01 00:00:00 1970 +0000
@@ -1,1 +1,1 @@
-first
+second
Testing diff --change when merge:
$ for i in 1 2 3 4 5 6 7 8 9 10; do
$ echo $i >> file.txt
$ done
$ hg commit -m "lots of text" # 3
$ sed -e 's,^2$,x,' file.txt > file.txt.tmp
$ mv file.txt.tmp file.txt
$ hg commit -m "change 2 to x" # 4
$ hg up -r 3
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ sed -e 's,^8$,y,' file.txt > file.txt.tmp
$ mv file.txt.tmp file.txt
$ hg commit -m "change 8 to y"
created new head
$ hg up -C -r 4
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg merge -r 5
merging file.txt
0 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg commit -m "merge 8 to y" # 6
$ hg diff --change 5
diff -r ae119d680c82 -r 9085c5c02e52 file.txt
--- a/file.txt Thu Jan 01 00:00:00 1970 +0000
+++ b/file.txt Thu Jan 01 00:00:00 1970 +0000
@@ -6,6 +6,6 @@
5
6
7
-8
+y
9
10
must be similar to 'hg diff --change 5':
$ hg diff -c 6
diff -r 273b50f17c6d -r 979ca961fd2e file.txt
--- a/file.txt Thu Jan 01 00:00:00 1970 +0000
+++ b/file.txt Thu Jan 01 00:00:00 1970 +0000
@@ -6,6 +6,6 @@
5
6
7
-8
+y
9
10