add version check to CI deploy

.github/workflows/tests.yml

@@ -64,6 +64,7 @@ jobs:
             submodules: recursive
       - run: perl -V
       - run: cpanm --notest --installdeps --verbose .
+      - run: cpanm MetaCPAN::Client
       - run: perl Build.PL
       - run: ./Build
       - run: ./Build deploy

Build.PL

@@ -10,9 +10,21 @@ my $deployer = Module::Build->subclass(
 sub ACTION_deploy {
 
     require CPAN::Uploader;
+    require MetaCPAN::Client;
+    use version;
+
     my $self = shift;
     $self->depends_on("dist");
 
+    # check that this is a newer version
+    my $name = $self->dist_name;
+    my $mpan = MetaCPAN::Client->new();
+    my $existing = $mpan->release($name)->version;
+    if (version->parse($existing) >= version->parse($self->dist_version)) {
+        warn "This version is <= the version on CPAN, aborting nicely\n";
+        return 1;
+    }
+
     my $tarball = $self->dist_dir() . '.tar.gz';
     die "tarball not found"
         if (! -e $tarball);