Print diagnostic messages on stderr, not stdout

dnf5-plugins/automatic_plugin/automatic.cpp

@@ -306,6 +306,7 @@ void AutomaticCommand::pre_configure() {
     }
 
     context.set_output_stream(output_stream);
+    context.set_error_stream(output_stream);
 }
 
 void AutomaticCommand::configure() {

dnf5-plugins/copr_plugin/copr_repo.cpp

@@ -395,7 +395,7 @@ std::string CoprRepo::get_projectname() {
 
 
 void CoprRepo::save_interactive() {
-    std::cout << COPR_THIRD_PARTY_WARNING;
+    std::cerr << COPR_THIRD_PARTY_WARNING;
     if (!libdnf5::cli::utils::userconfirm::userconfirm(base->get_config()))
         return;
 
@@ -416,9 +416,9 @@ void CoprRepo::save_interactive() {
             the_list << "     baseurl=" << repo.get_baseurl() << std::endl;
         }
 
-        std::cout << std::endl;
-        std::cout << libdnf5::utils::sformat(COPR_EXTERNAL_DEPS_WARNING, the_list.str());
-        std::cout << std::endl;
+        std::cerr << std::endl;
+        std::cerr << libdnf5::utils::sformat(COPR_EXTERNAL_DEPS_WARNING, the_list.str());
+        std::cerr << std::endl;
         if (!libdnf5::cli::utils::userconfirm::userconfirm(base->get_config())) {
             for (auto & p : repositories) {
                 auto & repo = p.second;

dnf5/commands/history/history_store.cpp

@@ -62,7 +62,7 @@ void HistoryStoreCommand::run() {
     trans_file_path /= TRANSACTION_JSON;
 
     if (std::filesystem::exists(trans_file_path)) {
-        std::cout << libdnf5::utils::sformat(
+        std::cerr << libdnf5::utils::sformat(
             _("File \"{}\" already exists, it will be overwritten.\n"), trans_file_path.string());
         // ask user for the file overwrite confirmation
         if (!libdnf5::cli::utils::userconfirm::userconfirm(get_context().get_base().get_config())) {

dnf5/context.cpp

@@ -70,18 +70,18 @@ class KeyImportRepoCB : public libdnf5::repo::RepoCallbacks {
             return false;
         }
 
-        std::cout << "Importing PGP key 0x" << key_info.get_short_key_id() << ":\n";
+        std::cerr << "Importing PGP key 0x" << key_info.get_short_key_id() << ":\n";
         for (auto & user_id : key_info.get_user_ids()) {
-            std::cout << " Userid     : \"" << user_id << "\"\n";
+            std::cerr << " Userid     : \"" << user_id << "\"\n";
         }
-        std::cout << " Fingerprint: " << key_info.get_fingerprint() << "\n";
-        std::cout << " From       : " << key_info.get_url() << std::endl;
+        std::cerr << " Fingerprint: " << key_info.get_fingerprint() << "\n";
+        std::cerr << " From       : " << key_info.get_url() << std::endl;
 
         return libdnf5::cli::utils::userconfirm::userconfirm(*config);
     }
 
     void repokey_imported([[maybe_unused]] const libdnf5::rpm::KeyInfo & key_info) override {
-        std::cout << _("The key was successfully imported.") << std::endl;
+        std::cerr << _("The key was successfully imported.") << std::endl;
     }
 
 private:
@@ -163,9 +163,12 @@ class Context::Impl {
     void set_load_available_repos(LoadAvailableRepos which) { load_available_repos = which; }
     LoadAvailableRepos get_load_available_repos() const noexcept { return load_available_repos; }
 
+    void print_output(std::string_view msg) const;
     void print_info(std::string_view msg) const;
+    void print_error(std::string_view msg) const;
 
-    void set_output_stream(std::ostream & new_output_stream) { output_stream = new_output_stream; }
+    void set_output_stream(std::ostream & new_output_stream) { out_stream = new_output_stream; }
+    void set_error_stream(std::ostream & new_error_stream) { err_stream = new_error_stream; }
 
     void set_transaction_store_path(std::filesystem::path path) { transaction_store_path = path; }
     const std::filesystem::path & get_transaction_store_path() const { return transaction_store_path; }
@@ -223,7 +226,8 @@ class Context::Impl {
     bool show_new_leaves{false};
     std::string get_cmd_line();
 
-    std::reference_wrapper<std::ostream> output_stream = std::cout;
+    std::reference_wrapper<std::ostream> out_stream = std::cout;
+    std::reference_wrapper<std::ostream> err_stream = std::cerr;
 
     std::unique_ptr<Plugins> plugins;
     std::unique_ptr<libdnf5::Goal> goal;
@@ -251,7 +255,7 @@ void Context::Impl::apply_repository_setopts() {
                 repo->get_config().opt_binds().at(key).new_string(
                     libdnf5::Option::Priority::COMMANDLINE, setopt.second);
             } catch (const std::exception & ex) {
-                std::cout << "setopt: \"" + setopt.first + "." + setopt.second + "\": " + ex.what() << std::endl;
+                print_error("setopt: \"" + setopt.first + "." + setopt.second + "\": " + ex.what());
             }
         }
     }
@@ -330,9 +334,9 @@ void Context::Impl::store_offline(libdnf5::base::Transaction & transaction) {
 
     auto & offline_data = state.get_data();
     if (offline_data.get_status() != libdnf5::offline::STATUS_DOWNLOAD_INCOMPLETE) {
-        std::cout << "There is already an offline transaction queued, initiated by the following command:" << std::endl
-                  << "\t" << offline_data.get_cmd_line() << std::endl
-                  << "Continuing will cancel the old offline transaction and replace it with this one." << std::endl;
+        print_error("There is already an offline transaction queued, initiated by the following command:");
+        print_error(fmt::format("\t{}", offline_data.get_cmd_line()));
+        print_error("Continuing will cancel the old offline transaction and replace it with this one.");
         if (!libdnf5::cli::utils::userconfirm::userconfirm(base.get_config())) {
             throw libdnf5::cli::AbortedByUserError();
         }
@@ -361,19 +365,19 @@ void Context::Impl::store_offline(libdnf5::base::Transaction & transaction) {
     print_info("Testing offline transaction");
     auto result = test_transaction.run();
     if (result != libdnf5::base::Transaction::TransactionRunResult::SUCCESS) {
-        std::cerr << "Transaction failed: " << libdnf5::base::Transaction::transaction_result_to_string(result)
-                  << std::endl;
+        print_error(
+            fmt::format("Transaction failed: {}", libdnf5::base::Transaction::transaction_result_to_string(result)));
         for (auto const & entry : transaction.get_gpg_signature_problems()) {
-            std::cerr << entry << std::endl;
+            print_error(entry);
         }
         for (auto & problem : test_transaction.get_transaction_problems()) {
-            std::cerr << "  - " << problem << std::endl;
+            print_error(fmt::format("  - {}", problem));
         }
         throw libdnf5::cli::SilentCommandExitError(1);
     }
 
     for (auto const & entry : test_transaction.get_gpg_signature_problems()) {
-        std::cerr << entry << std::endl;
+        print_error(entry);
     }
 
     // Download and transaction test complete. Fill out entries in offline
@@ -411,9 +415,9 @@ void Context::Impl::download_and_run(libdnf5::base::Transaction & transaction) {
         constexpr const char * comps_in_trans_dir{"./comps"};
         auto comps_location = transaction_store_path / comps_in_trans_dir;
         if (std::filesystem::exists(transaction_location)) {
-            std::cout << libdnf5::utils::sformat(
-                _("Location \"{}\" already contains a stored transaction, it will be overwritten.\n"),
-                transaction_store_path.string());
+            print_error(libdnf5::utils::sformat(
+                _("Location \"{}\" already contains a stored transaction, it will be overwritten."),
+                transaction_store_path.string()));
             if (libdnf5::cli::utils::userconfirm::userconfirm(base.get_config())) {
                 std::filesystem::remove_all(packages_location);
                 std::filesystem::remove_all(comps_location);
@@ -448,10 +452,10 @@ void Context::Impl::download_and_run(libdnf5::base::Transaction & transaction) {
 
     if (should_store_offline) {
         store_offline(transaction);
-        std::cout << "Transaction stored to be performed offline. Run `dnf5 offline reboot` to reboot and run the "
-                     "transaction. To cancel the transaction and delete the downloaded files, use `dnf5 "
-                     "offline clean`."
-                  << std::endl;
+        print_info(
+            "Transaction stored to be performed offline. Run `dnf5 offline reboot` to reboot and run the "
+            "transaction. To cancel the transaction and delete the downloaded files, use `dnf5 "
+            "offline clean`.");
         return;
     }
 
@@ -483,19 +487,19 @@ void Context::Impl::download_and_run(libdnf5::base::Transaction & transaction) {
     auto result = transaction.run();
     print_info("");
     if (result != libdnf5::base::Transaction::TransactionRunResult::SUCCESS) {
-        std::cerr << "Transaction failed: " << libdnf5::base::Transaction::transaction_result_to_string(result)
-                  << std::endl;
+        print_error(
+            fmt::format("Transaction failed: {}", libdnf5::base::Transaction::transaction_result_to_string(result)));
         for (auto const & entry : transaction.get_gpg_signature_problems()) {
-            std::cerr << entry << std::endl;
+            print_error(entry);
         }
         for (auto & problem : transaction.get_transaction_problems()) {
-            std::cerr << "  - " << problem << std::endl;
+            print_error(problem);
         }
         throw libdnf5::cli::SilentCommandExitError(1);
     }
 
     for (auto const & entry : transaction.get_gpg_signature_problems()) {
-        std::cerr << entry << std::endl;
+        print_error(entry);
     }
     // TODO(mblaha): print a summary of successful transaction
 }
@@ -507,11 +511,17 @@ libdnf5::Goal * Context::Impl::get_goal(bool new_if_not_exist) {
     return goal.get();
 }
 
+void Context::Impl::print_output(std::string_view msg) const {
+    out_stream.get() << msg << std::endl;
+}
 void Context::Impl::print_info(std::string_view msg) const {
     if (!quiet) {
-        output_stream.get() << msg << std::endl;
+        err_stream.get() << msg << std::endl;
     }
 }
+void Context::Impl::print_error(std::string_view msg) const {
+    err_stream.get() << msg << std::endl;
+}
 
 
 Context::Context(std::vector<std::unique_ptr<libdnf5::Logger>> && loggers)
@@ -645,12 +655,21 @@ Context::LoadAvailableRepos Context::get_load_available_repos() const noexcept {
     return p_impl->get_load_available_repos();
 }
 
+void Context::print_output(std::string_view msg) const {
+    p_impl->print_output(msg);
+}
 void Context::print_info(std::string_view msg) const {
     p_impl->print_info(msg);
 }
+void Context::print_error(std::string_view msg) const {
+    p_impl->print_error(msg);
+}
 void Context::set_output_stream(std::ostream & new_output_stream) {
     p_impl->set_output_stream(new_output_stream);
 }
+void Context::set_error_stream(std::ostream & new_error_stream) {
+    p_impl->set_error_stream(new_error_stream);
+}
 
 void Context::set_transaction_store_path(std::filesystem::path path) {
     p_impl->set_transaction_store_path(path);

dnf5/download_callbacks.cpp

@@ -104,7 +104,7 @@ int DownloadCallbacks::mirror_failure(void * user_cb_data, const char * msg, con
 void DownloadCallbacks::reset_progress_bar() {
     multi_progress_bar.reset();
     if (printed) {
-        std::cout << std::endl;
+        std::cerr << std::endl;
         printed = false;
     }
 }

dnf5/include/dnf5/context.hpp

@@ -136,11 +136,19 @@ class DNF_API Context : public libdnf5::cli::session::Session {
     void set_load_available_repos(LoadAvailableRepos which);
     LoadAvailableRepos get_load_available_repos() const noexcept;
 
-    /// If quiet mode is not active, it will print `msg` to standard output.
+    /// Print `msg` to the output stream, which by default is stdout.
+    void print_output(std::string_view msg) const;
+
+    /// If quiet mode is not active, it will print `msg` to the error stream, which by default is stderr.
     void print_info(std::string_view msg) const;
 
+    /// Print `msg` to the error stream, which by default is stderr.
+    void print_error(std::string_view msg) const;
+
     void set_output_stream(std::ostream & new_output_stream);
 
+    void set_error_stream(std::ostream & new_error_stream);
+
     // When set current transaction is not executed but rather stored to the specified path.
     void set_transaction_store_path(std::filesystem::path path);
     const std::filesystem::path & get_transaction_store_path() const;