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.

     1

EVERYTHING

     2

diff -r ec612a6291f1 alpha/one

     3

--- a/alpha/one

     4

+++ b/alpha/one

     5

@@ -0,0 +1,1 @@

     6

+1

     7

diff -r ec612a6291f1 beta/two

     8

--- a/beta/two

     9

+++ b/beta/two

    10

@@ -0,0 +1,1 @@

    11

+2

    12

BETA ONLY

    13

diff -r ec612a6291f1 beta/two

    14

--- a/beta/two

    15

+++ b/beta/two

    16

@@ -0,0 +1,1 @@

    17

+2

    18

INSIDE BETA

    19

diff -r ec612a6291f1 beta/two

    20

--- a/beta/two

    21

+++ b/beta/two

    22

@@ -0,0 +1,1 @@

    23

+2