[PATCH] cvsimport: skip commits that are too recent

[Martin Langhoff <martin@catalyst.net.nz>]

With this patch, cvsimport will skip commits made
in the last 10 minutes. The recent-ness test is of
5 minutes + cvsps fuzz window (5 minutes default).

To force recent commits to be imported, pass the
-a(ll) flag.

When working with a CVS repository that is in use,
importing commits that are too recent can lead to
partially incorrect trees. This is mainly due to

 - Commits that are within the cvsps fuzz window may later
   be found to have affected more files.

 - When performing incremental imports, clock drift between
   the systems may lead to skipped commits.

This commit helps keep incremental imports of in-use
CVS repositories sane.

Signed-off-by: Martin Langhoff <martin@catalyst.net.nz>
---
 Documentation/git-cvsimport.txt |    7 ++++++-
 git-cvsimport.perl              |   20 ++++++++++++++++++--
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/Documentation/git-cvsimport.txt b/Documentation/git-cvsimport.txt
index d21d66b..6deee94 100644
--- a/Documentation/git-cvsimport.txt
+++ b/Documentation/git-cvsimport.txt
@@ -90,7 +90,8 @@ If you need to pass multiple options, separate them with a comma.
 	Print a short usage message and exit.
 
 -z <fuzz>::
-        Pass the timestamp fuzz factor to cvsps.
+	Pass the timestamp fuzz factor to cvsps, in seconds. If unset,
+	cvsps defaults to 300s.
 
 -s <subst>::
 	Substitute the character "/" in branch names with <subst>
@@ -99,6 +100,10 @@ If you need to pass multiple options, separate them with a comma.
 	CVS by default uses the unix username when writing its
 	commit logs. Using this option and an author-conv-file
 	in this format
+
+-a::
+	Import all commits, including recent ones. cvsimport by default
+	skips commits that have a timestamp less than 10 minutes ago.
 +
 ---------
 	exon=Andreas Ericsson <ae@op5.se>
diff --git a/git-cvsimport.perl b/git-cvsimport.perl
index c5bf2d1..a75aaa3 100755
--- a/git-cvsimport.perl
+++ b/git-cvsimport.perl
@@ -29,7 +29,7 @@ use IPC::Open2;
 $SIG{'PIPE'}="IGNORE";
 $ENV{'TZ'}="UTC";
 
-our ($opt_h,$opt_o,$opt_v,$opt_k,$opt_u,$opt_d,$opt_p,$opt_C,$opt_z,$opt_i,$opt_P, $opt_s,$opt_m,$opt_M,$opt_A,$opt_S,$opt_L);
+our ($opt_h,$opt_o,$opt_v,$opt_k,$opt_u,$opt_d,$opt_p,$opt_C,$opt_z,$opt_i,$opt_P, $opt_s,$opt_m,$opt_M,$opt_A,$opt_S,$opt_L, $opt_a);
 my (%conv_author_name, %conv_author_email);
 
 sub usage() {
@@ -37,7 +37,7 @@ sub usage() {
 Usage: ${\basename $0}     # fetch/update GIT from CVS
        [-o branch-for-HEAD] [-h] [-v] [-d CVSROOT] [-A author-conv-file]
        [-p opts-for-cvsps] [-C GIT_repository] [-z fuzz] [-i] [-k] [-u]
-       [-s subst] [-m] [-M regex] [-S regex] [CVS_module]
+       [-s subst] [-a] [-m] [-M regex] [-S regex] [CVS_module]
 END
 	exit(1);
 }
@@ -105,6 +105,8 @@ if ($opt_d) {
 }
 $opt_o ||= "origin";
 $opt_s ||= "-";
+$opt_a ||= 0;
+
 my $git_tree = $opt_C;
 $git_tree ||= ".";
 
@@ -129,6 +131,11 @@ if ($opt_M) {
 	push (@mergerx, qr/$opt_M/);
 }
 
+# Remember UTC of our starting time
+# we'll want to avoid importing commits
+# that are too recent
+our $starttime = time();
+
 select(STDERR); $|=1; select(STDOUT);
 
 
@@ -824,6 +831,15 @@ while (<CVS>) {
 			$state = 11;
 			next;
 		}
+		if ( !$opt_a && $starttime - 300 - (defined $opt_z ? $opt_z : 300) <= $date) {
+			# skip if the commit is too recent
+			# that the cvsps default fuzz is 300s, we give ourselves another
+			# 300s just in case -- this also prevents skipping commits
+			# due to server clock drift
+			print "skip patchset $patchset: $date too recent\n" if $opt_v;
+			$state = 11;
+			next;
+		}
 		if (exists $ignorebranch{$branch}) {
 			print STDERR "Skipping $branch\n";
 			$state = 11;
-- 
1.5.0.rc0.g4017-dirty