convert: add a mode where mercurial_sink skips empty revisions.
The getchanges function of some converter_source classes can return
some false positives. I.e. they sometimes claim that a file "foo"
was changed in some revision, even though its contents are still the
same.
convert_svn is particularly bad, but I think this can also happen with
convert_cvs and, at least in theory, with mercurial_source.
For regular conversions this is not really a problem - as long as
getfile returns the right contents, we'll get a converted revision
with the right contents. But when we use --filemap, this could lead
to superfluous revisions being converted.
Instead of fixing every converter_source, I decided to change
mercurial_sink to work around this problem.
When --filemap is used, we're interested only in revisions that touch
some specific files. If a revision doesn't change any of these files,
then we're not interested in it (at least for revisions with a single
parent; merges are special).
For mercurial_sink, we abuse this property and rollback a commit if
the manifest text hasn't changed. This avoids duplicating the logic
from localrepo.filecommit to detect unchanged files.
quiet:
--- a/foo Mon Jan 12 13:46:40 1970 +0000
+++ b/foo Mon Jan 12 13:46:41 1970 +0000
@@ -1,1 +1,1 @@ bar
-bar
+foobar
normal:
diff -r 74de3f1392e2 -r b8b5f023a6ad foo
--- a/foo Mon Jan 12 13:46:40 1970 +0000
+++ b/foo Mon Jan 12 13:46:41 1970 +0000
@@ -1,1 +1,1 @@ bar
-bar
+foobar
verbose:
diff -r 74de3f1392e2 -r b8b5f023a6ad foo
--- a/foo Mon Jan 12 13:46:40 1970 +0000
+++ b/foo Mon Jan 12 13:46:41 1970 +0000
@@ -1,1 +1,1 @@ bar
-bar
+foobar
debug:
diff -r 74de3f1392e2d67856fb155963441f2610494e1a -r b8b5f023a6ad77fc378bd95cf3fa00cd1414d107 foo
--- a/foo Mon Jan 12 13:46:40 1970 +0000
+++ b/foo Mon Jan 12 13:46:41 1970 +0000
@@ -1,1 +1,1 @@ bar
-bar
+foobar