import: take advantage of some Perl 5.10.x features

We can save a few lines of code this way and reduce the
verbosity of some lines we keep.

diff --git a/lib/PublicInbox/Import.pm b/lib/PublicInbox/Import.pm
index 60ce7b66419b3ee0e9ad2dca4b93644497539378..aef49033cc4e0d4767a67d1ec78643b6ab05be2d 100644 (file)
--- a/lib/PublicInbox/Import.pm
+++ b/lib/PublicInbox/Import.pm
@@ -1,4 +1,4 @@
-# Copyright (C) 2016-2021 all contributors <meta@public-inbox.org>
+# Copyright (C) all contributors <meta@public-inbox.org>
 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
 #
 # git fast-import-based ssoma-mda MDA replacement
@@ -103,7 +103,7 @@ sub _check_path ($$$$) {
        return if $tip eq '';
        print $w "ls $tip $path\n" or wfail;
        local $/ = "\n";
-       defined(my $info = <$r>) or die "EOF from fast-import: $!";
+       my $info = <$r> // die "EOF from fast-import: $!";
        $info =~ /\Amissing / ? undef : $info;
 }
 
@@ -111,22 +111,21 @@ sub _cat_blob ($$$) {
        my ($r, $w, $oid) = @_;
        print $w "cat-blob $oid\n" or wfail;
        local $/ = "\n";
-       my $info = <$r>;
-       defined $info or die "EOF from fast-import / cat-blob: $!";
+       my $info = <$r> // die "EOF from fast-import / cat-blob: $!";
        $info =~ /\A[a-f0-9]{40,} blob ([0-9]+)\n\z/ or return;
        my $left = $1;
        my $offset = 0;
        my $buf = '';
        my $n;
        while ($left > 0) {
-               $n = read($r, $buf, $left, $offset);
-               defined($n) or die "read cat-blob failed: $!";
+               $n = read($r, $buf, $left, $offset) //
+                       die "read cat-blob failed: $!";
                $n == 0 and die 'fast-export (cat-blob) died';
                $left -= $n;
                $offset += $n;
        }
-       $n = read($r, my $lf, 1);
-       defined($n) or die "read final byte of cat-blob failed: $!";
+       $n = read($r, my $lf, 1) //
+               die "read final byte of cat-blob failed: $!";
        die "bad read on final byte: <$lf>" if $lf ne "\n";
 
        # fixup some bugginess in old versions:
@@ -148,10 +147,8 @@ sub check_remove_v1 {
        my $oid = $1;
        my $msg = _cat_blob($r, $w, $oid) or die "BUG: cat-blob $1 failed";
        my $cur = PublicInbox::Eml->new($msg);
-       my $cur_s = $cur->header('Subject');
-       $cur_s = '' unless defined $cur_s;
-       my $cur_m = $mime->header('Subject');
-       $cur_m = '' unless defined $cur_m;
+       my $cur_s = $cur->header('Subject') // '';
+       my $cur_m = $mime->header('Subject') // '';
        if ($cur_s ne $cur_m || norm_body($cur) ne norm_body($mime)) {
                return ('MISMATCH', $cur);
        }
@@ -219,7 +216,7 @@ sub get_mark {
        die "not active\n" unless $self->{in};
        my ($r, $w) = $self->gfi_start;
        print $w "get-mark $mark\n" or wfail;
-       defined(my $oid = <$r>) or die "get-mark failed, need git 2.6.0+\n";
+       my $oid = <$r> // die "get-mark failed, need git 2.6.0+\n";
        chomp($oid);
        $oid;
 }