Have load_config() and write_(min_)config() return messages

Hardcoding load_config() and write_(min_)config() to write any message
to stdout is awkward, because it means that the message can't be easily
reused when stdout is the wrong place to write it to (e.g. in
menuconfig/guiconfig). This gets extra bad now that there's also the "No
change to ..." message.

Modify load_config() and write_(min_)config() to return the message as a
string instead, and have them always return a message, instead of just
when 'filename' is None and verbose=True. This makes things flexible and
straightforward.

Use the new behavior in menuconfig.py and guiconfig.py. They now show
"No change to ..." when saving a file doesn't modify it.

Tools that want to write messages to stdout should now do
print(kconf.load_config()) / print(kconf.write_config()).

There's no clean way to preserve perfect backwards compatibility here,
but keep accepting the 'verbose' argument and print a deprecation
warning if a value is ever passed for it. That way, scripts will keep
running, though possibly with less output on stdout.

This changes the meaning of the load_config() return value as well,
though I suspect it was only ever used by the menuconfig/guiconfig
interfaces.

The new behavior applies for kconfiglib.VERSION >= (12, 0, 0).

1 files changed, 19 insertions, 13 deletions

diff --git a/menuconfig.py b/menuconfig.py
index 3dbee95..a7f921b 100755
--- a/menuconfig.py
+++ b/menuconfig.py
@@ -650,12 +650,12 @@ def menuconfig(kconf):
 
     _kconf = kconf
 
-    # Load existing configuration and set _conf_changed True if it is outdated
-    _conf_changed = _load_config()
-
     # Filename to save configuration to
     _conf_filename = standard_config_filename()
 
+    # Load existing configuration and set _conf_changed True if it is outdated
+    _conf_changed = _load_config()
+
     # Filename to save minimal configuration to
     _minconf_filename = "defconfig"
 
@@ -710,7 +710,8 @@ def _load_config():
     # Returns True if .config is missing or outdated. We always prompt for
     # saving the configuration in that case.
 
-    if not _kconf.load_config():
+    print(_kconf.load_config())
+    if not os.path.exists(_conf_filename):
         # No .config
         return True
 
@@ -922,8 +923,9 @@ def _quit_dialog():
             return None
 
         if c == "y":
-            if _try_save(_kconf.write_config, _conf_filename, "configuration"):
-                return "Configuration saved to '{}'".format(_conf_filename)
+            msg = _try_save(_kconf.write_config, _conf_filename, "configuration")
+            if msg:
+                return msg
 
         elif c == "n":
             return "Configuration ({}) was not saved".format(_conf_filename)
@@ -1858,29 +1860,33 @@ def _save_dialog(save_fn, default_filename, description):
 
         filename = os.path.expanduser(filename)
 
-        if _try_save(save_fn, filename, description):
-            _msg("Success", "{} saved to {}".format(description, filename))
+        msg = _try_save(save_fn, filename, description)
+        if msg:
+            _msg("Success", msg)
             return filename
 
 
 def _try_save(save_fn, filename, description):
-    # Tries to save a configuration file. Pops up an error and returns False on
-    # failure.
+    # Tries to save a configuration file. Returns a message to print on
+    # success.
     #
     # save_fn:
     #   Function to call with 'filename' to save the file
     #
     # description:
     #   String describing the thing being saved
+    #
+    # Return value:
+    #   A message to print on success, and None on failure
 
     try:
-        save_fn(filename)
-        return True
+        # save_fn() returns a message to print
+        return save_fn(filename)
     except OSError as e:
         _error("Error saving {} to '{}'\n\n{} (errno: {})"
                .format(description, e.filename, e.strerror,
                        errno.errorcode[e.errno]))
-        return False
+        return None
 
 
 def _key_dialog(title, text, keys):