index: --reindex w/ --{since,until,before,after}

This lets administrators reindex specific time ranges
according to git "approxidate" formats.  These arguments
are passed directly to underlying git-log(1) invocations
and may still reach into old epochs.

Since these options rely on git committer dates (which we infer
from the most recent Received: header), they are not guaranteed
to be strictly tied to git history and it's possible to
over/under-reindex some messages.  It's probably not a major
problem in practice, though; reindexing a few extra messages
is generally harmless aside from some extra device wear.

Since this currently relies on git-log, these options do not
affect -extindex, yet.

1 files changed, 7 insertions, 1 deletions

diff --git a/lib/PublicInbox/V2Writable.pm b/lib/PublicInbox/V2Writable.pm
index 971b007b..36b84f57 100644
--- a/lib/PublicInbox/V2Writable.pm
+++ b/lib/PublicInbox/V2Writable.pm
@@ -876,6 +876,11 @@ sub update_last_commit {
                 chomp(my $n = $unit->{git}->qx(@cmd));
                 return if $n ne '' && $n == 0;
         }
+        # don't rewind if --{since,until,before,after} are in use
+        return if (defined($last) &&
+                        grep(defined, @{$sync->{-opt}}{qw(since until)}) &&
+                        is_ancestor($self->git, $latest_cmt, $last));
+
         last_epoch_commit($self, $unit->{epoch}, $latest_cmt);
 }
 
@@ -1337,7 +1342,8 @@ sub index_sync {
         }
 
         # reindex does not pick up new changes, so we rerun w/o it:
-        if ($opt->{reindex} && !$sync->{quit}) {
+        if ($opt->{reindex} && !$sync->{quit} &&
+                        !grep(defined, @$opt{qw(since until)})) {
                 my %again = %$opt;
                 $sync = undef;
                 delete @again{qw(rethread reindex -skip_lock)};