fix: let dashd -version, -help and first start work without an existing data directory

doc/release-notes-8029.md

@@ -0,0 +1,4 @@
+Configuration
+-------------
+
+- `dashd` no longer creates an empty `dash.conf` when none exists, matching Bitcoin Core. `dash-qt`'s "Open Configuration File" still creates it on demand. (#8029)

src/qt/guiutil.cpp

@@ -599,6 +599,10 @@ void openConfigfile()
 {
     fs::path pathConfig = gArgs.GetConfigFilePath();
 
+    /* Create the file */
+    std::ofstream configFile{pathConfig, std::ios_base::app};
+    configFile.close();
+
     /* Open dash.conf with the associated application */
     if (fs::exists(pathConfig)) {
         // Workaround for macOS-specific behavior; see #15409.

src/util/system.cpp

@@ -990,13 +990,6 @@ bool ArgsManager::ReadConfigFiles(std::string& error, bool ignore_invalid_keys)
                 tfm::format(std::cerr, "warning: -includeconf cannot be used from included files; ignoring -includeconf=%s\n", conf_file_name);
             }
         }
-    } else {
-        // Create an empty dash.conf if it does not exist
-        std::ofstream configFile{conf_path, std::ios_base::app};
-        if (!configFile.good())
-            return false;
-        configFile.close();
-        return true; // Nothing to read, so just return
     }
 
     // If datadir is changed in .conf file:

test/functional/feature_config_args.py

@@ -336,6 +336,27 @@ def test_ignored_conf(self):
         self.start_node(0, [f'-conf={node.datadir}/dash.conf'])
         self.stop_node(0)
 
+    def test_missing_default_datadir(self):
+        # Overriding the default datadir through the environment does not work on Windows
+        if sys.platform == "win32":
+            return
+
+        self.log.info('Test -version, -help and a first start without a default data directory')
+        node = self.nodes[0]
+        node_args = node.args
+        node.args = [arg for arg in node.args if not arg.startswith("-datadir=")]
+        for name, extra_args in [("version", ["-version"]), ("help", ["-help"]), ("start", ["-regtest", "-listen=0", "-server=0"])]:
+            env, default_datadir = util.get_temp_default_datadir(pathlib.Path(self.options.tmpdir, "no_datadir", name))
+            default_datadir.parent.mkdir(parents=True)
+            node.start(extra_args, env=env)
+            if name == "start":
+                debug_log = default_datadir / "regtest" / "debug.log"
+                self.wait_until(lambda: node.process.poll() is not None or (debug_log.exists() and "Done loading" in debug_log.read_text(encoding="utf-8")))
+                assert node.process.poll() is None
+                node.process.terminate()
+            node.wait_until_stopped()
+        node.args = node_args
+
     def test_ignored_default_conf(self):
         # Disable this test for windows currently because trying to override
         # the default datadir through the environment does not seem to work.
@@ -394,6 +415,7 @@ def run_test(self):
         self.test_config_file_log()
         self.test_invalid_command_line_options()
         self.test_ignored_conf()
+        self.test_missing_default_datadir()
         self.test_ignored_default_conf()
         self.test_acceptstalefeeestimates_arg_support()