Enhance warning about RPMs that were not validate by RPM

DNF5 informs about number of packages that signature was not
verified, but without any additional detail. The ID of repository
provides a good hint for user why the check was skipped. The behavior
is related to configuration options which some of them  are repo
specific or specific for commandline repository. If user wants to verify
everything, the hint provides sufficient information which configuration
of repository should be modified.

Closes: #1311

libdnf5/base/transaction.cpp

@@ -1315,7 +1315,8 @@ bool Transaction::Impl::check_gpg_signatures() {
     // TODO(mblaha): DNSsec key verification
     libdnf5::rpm::RpmSignature rpm_signature(base);
     std::set<std::string> processed_repos{};
-    int num_checks_skipped = 0;
+    unsigned long num_checks_skipped = 0;
+    std::set<std::string> repos_with_skipped_checks;
     for (const auto & trans_pkg : packages) {
         if (transaction_item_action_is_inbound(trans_pkg.get_action())) {
             auto const & pkg = trans_pkg.get_package();
@@ -1328,6 +1329,7 @@ bool Transaction::Impl::check_gpg_signatures() {
             auto check_result = rpm_signature.check_package_signature(pkg);
             if (check_result == libdnf5::rpm::RpmSignature::CheckResult::SKIPPED) {
                 num_checks_skipped += 1;
+                repos_with_skipped_checks.insert(pkg.get_repo_id());
             } else if (check_result != libdnf5::rpm::RpmSignature::CheckResult::OK) {
                 // these two errors are possibly recoverable by importing the correct public key
                 auto is_error_recoverable =
@@ -1366,7 +1368,17 @@ bool Transaction::Impl::check_gpg_signatures() {
         }
     }
     if (num_checks_skipped > 0) {
-        auto warning_msg = utils::sformat(_("Warning: skipped PGP checks for {} package(s)."), num_checks_skipped);
+        auto repo_string = libdnf5::utils::string::join(
+            repos_with_skipped_checks, C_("It is a joining character for repositories IDs", ", "));
+        auto warning_msg =
+            (num_checks_skipped == 1)
+                ? utils::sformat(_("Warning: skipped PGP checks for 1 package from repository: {}"), repo_string)
+                : utils::sformat(
+                      P_("Warning: skipped PGP checks for {0} packages from repository: {1}",
+                         "Warning: skipped PGP checks for {0} packages from repositories: {1}",
+                         repos_with_skipped_checks.size()),
+                      num_checks_skipped,
+                      repo_string);
         signature_problems.push_back(warning_msg);
     }
     return result;

test/libdnf5/base/test_transaction.cpp

@@ -38,7 +38,8 @@ void BaseTransactionTest::test_check_gpg_signatures_no_gpgcheck() {
     CPPUNIT_ASSERT(transaction.check_gpg_signatures());
     CPPUNIT_ASSERT_EQUAL((size_t)1, transaction.get_gpg_signature_problems().size());
     CPPUNIT_ASSERT_EQUAL(
-        std::string("Warning: skipped PGP checks for 1 package(s)."), transaction.get_gpg_signature_problems()[0]);
+        std::string("Warning: skipped PGP checks for 1 package from repository: repomd-repo1"),
+        transaction.get_gpg_signature_problems()[0]);
 }
 
 void BaseTransactionTest::test_check_gpg_signatures_fail() {

test/python3/libdnf5/base/test_transaction.py

@@ -32,7 +32,7 @@ def test_check_gpg_signatures_no_gpgcheck(self):
 
         self.assertEqual(1, transaction.get_transaction_packages_count())
         self.assertTrue(transaction.check_gpg_signatures())
-        self.assertEqual(('Warning: skipped PGP checks for 1 package(s).',),
+        self.assertEqual(('Warning: skipped PGP checks for 1 package from repository: repomd-repo1',),
                          transaction.get_gpg_signature_problems())
 
     def test_check_gpg_signatures_fail(self):