[fix] Update prompt to handle case with a socket and a host of None (resolves #707)

changelog.md

@@ -1,6 +1,15 @@
 Upcoming (TBD)
 ==============
 
+Bug Fixes
+--------
+* Update the prompt display logic to handle an edge case where a socket is used without
+  a host being parsed from any other method (#707).
+
+
+1.42.0 (2025/12/20)
+==============
+
 Features
 --------
 * Add support for the automatic displaying of warnings after a SQL statement is executed.

mycli/main.py

@@ -1193,10 +1193,15 @@ def get_prompt(self, string: str) -> str:
         assert sqlexecute is not None
         assert sqlexecute.server_info is not None
         assert sqlexecute.server_info.species is not None
-        host = self.login_path if self.login_path and self.login_path_as_host else sqlexecute.host
+        if self.login_path and self.login_path_as_host:
+            prompt_host = self.login_path
+        elif sqlexecute.host is not None:
+            prompt_host = sqlexecute.host
+        else:
+            prompt_host = "localhost"
         now = datetime.now()
         string = string.replace("\\u", sqlexecute.user or "(none)")
-        string = string.replace("\\h", host or "(none)")
+        string = string.replace("\\h", prompt_host or "(none)")
         string = string.replace("\\d", sqlexecute.dbname or "(none)")
         string = string.replace("\\t", sqlexecute.server_info.species.name)
         string = string.replace("\\n", "\n")

test/test_main.py

@@ -11,7 +11,7 @@
 
 from mycli.main import MyCli, cli, thanks_picker
 from mycli.packages.special.main import COMMANDS as SPECIAL_COMMANDS
-from mycli.sqlexecute import ServerInfo
+from mycli.sqlexecute import ServerInfo, SQLExecute
 from test.utils import HOST, PASSWORD, PORT, USER, dbtest, run
 
 test_dir = os.path.abspath(os.path.dirname(__file__))
@@ -37,6 +37,21 @@
 ]
 
 
+@dbtest
+def test_prompt_no_host_only_socket(executor):
+    mycli = MyCli()
+    mycli.prompt_format = "\\t \\u@\\h:\\d> "
+    mycli.sqlexecute = SQLExecute
+    mycli.sqlexecute.server_info = ServerInfo.from_version_string("8.0.44-0ubuntu0.24.04.1")
+    mycli.sqlexecute.host = None
+    mycli.sqlexecute.socket = "/var/run/mysqld/mysqld.sock"
+    mycli.sqlexecute.user = "root"
+    mycli.sqlexecute.dbname = "mysql"
+    mycli.sqlexecute.port = "3306"
+    prompt = mycli.get_prompt(mycli.prompt_format)
+    assert prompt == "MySQL root@localhost:mysql> "
+
+
 @dbtest
 def test_enable_show_warnings(executor):
     mycli = MyCli()