handle receiving same file more than once

`scan-dir`, because of `IO.watch`, can emit the same path multiple
times; we don't want messing up the index (especially the bayesian
one!) because of that

1 files changed, 5 insertions, 1 deletions

diff --git a/lib/MaildirIndexer/Index/ByAddresses.rakumod b/lib/MaildirIndexer/Index/ByAddresses.rakumod
index b83a239..ab0d5bb 100644
--- a/lib/MaildirIndexer/Index/ByAddresses.rakumod
+++ b/lib/MaildirIndexer/Index/ByAddresses.rakumod
@@ -31,6 +31,10 @@ submethod account-for(Str @addresses,Str $mailbox,Int $step) {
 
 method add-mail(MaildirIndexer::Email:D $email, Str:D $mailbox --> Nil) {
     MaildirIndexer::LogTimelineSchema::Index::Add.log: :class('ByAddresses'),:$mailbox, -> {
+        # ignore adding the same file twice, files in maildirs are
+        # immutable
+        return if %!addresses-for-file{ $email.path }:exists;
+
         my Str @addresses = $email.addresses or return;
         %!addresses-for-file{ $email.path } = @addresses;
 
@@ -42,7 +46,7 @@ method add-mail(MaildirIndexer::Email:D $email, Str:D $mailbox --> Nil) {
 
 method del-path(IO:D $file, Str:D $mailbox --> Nil) {
     MaildirIndexer::LogTimelineSchema::Index::Rm.log: :class('ByAddresses'),:$mailbox, -> {
-        my Str @addresses = %!addresses-for-file{$file.path} or return;
+        my Str @addresses = %!addresses-for-file{$file.path}:delete or return;
 
         self.account-for(@addresses,$mailbox,-1);