Move sys.stdout redirect to top.

* In `develop` config import will set up logging, so let's head that off
  at the pass and put the redirect right at the top.
* Also moved the EDMCLogging import to right after the config import's
  new position, to emulate `develop` behaviour.
* We *append* on the initial open of the redirect log file.  Then once
  we're sure we're the only process we truncate this.

EDMarketConnector.py

@@ -15,11 +15,25 @@ from sys import platform
 from time import localtime, strftime, time
 from typing import TYPE_CHECKING
 
-from config import appversion, appversion_nobuild, config, copyright
 from constants import applongname, appname, protocolhandler_redirect
 
 # config will now cause an appname logger to be set up, so we need the
 # console redirect before this
+if __name__ == '__main__':
+    # Keep this as the very first code run to be as sure as possible of no
+    # output until after this redirect is done, if needed.
+    if getattr(sys, 'frozen', False):
+        # By default py2exe tries to write log to dirname(sys.executable) which fails when installed
+        import tempfile
+
+        # unbuffered not allowed for text in python3, so use `1 for line buffering
+        sys.stdout = sys.stderr = open(join(tempfile.gettempdir(), f'{appname}.log'), mode='a', buffering=1)
+    # TODO: Test: Make *sure* this redirect is working, else py2exe is going to cause an exit popup
+
+# After the redirect in case config does logging setup
+from config import appversion, appversion_nobuild, config, copyright
+from EDMCLogging import edmclogger, logger, logging
+
 if __name__ == '__main__':
     # Command-line arguments
     parser = argparse.ArgumentParser(
@@ -165,16 +179,9 @@ if __name__ == '__main__':
         root.mainloop()
 
     if not no_other_instance_running():
-        # There's a copy already running.  We want to inform the user by
-        # **appending** to the log file, not truncating it.
-        if getattr(sys, 'frozen', False):
-            # By default py2exe tries to write log to dirname(sys.executable) which fails when installed
-            import tempfile
+        # There's a copy already running.
 
-            # unbuffered not allowed for text in python3, so use `1 for line buffering
-            sys.stdout = sys.stderr = open(join(tempfile.gettempdir(), f'{appname}.log'), mode='a', buffering=1)
-
-        # Logging isn't set up yet.
+        # Logging isn't set up yet. # TODO: Actually it will be by now in `develop`
         # We'll keep this print, but it will be over-written by any subsequent
         # write by the already-running process.
         print("An EDMarketConnector.exe process was already running, exiting.")
@@ -185,18 +192,10 @@ if __name__ == '__main__':
         # reach here.
         sys.exit(0)
 
-    # Keep this as the very first code run to be as sure as possible of no
-    # output until after this redirect is done, if needed.
     if getattr(sys, 'frozen', False):
-        # By default py2exe tries to write log to dirname(sys.executable) which fails when installed
-        import tempfile
+        # Now that we're sure we're the only instance running we can truncate the logfile
+        sys.stdout.truncate()
 
-        # unbuffered not allowed for text in python3, so use `1 for line buffering
-        sys.stdout = sys.stderr = open(join(tempfile.gettempdir(), f'{appname}.log'), mode='wt', buffering=1)
-    # TODO: Test: Make *sure* this redirect is working, else py2exe is going to cause an exit popup
-
-
-from EDMCLogging import edmclogger, logger, logging
 
 # See EDMCLogging.py docs.
 # isort: off