Give symbol locations in merge_config.py warnings

Helpful for debugging.

Piggyback some small fixes:

 - Don't imply that merge_config.py is an executable file or that it
   only runs under Python 3. Remove the hashbang line and fix the
   example in the overview.

 - Add some #'s to the overview .config files that had accidentally been
   left out.

 - Fix a questionable sentence in oldconfig.py's name_and_loc_str()
   docstring.

2 files changed, 23 insertions, 10 deletions

diff --git a/examples/merge_config.py b/examples/merge_config.py
index bc6e4b8..a6110f8 100644
--- a/examples/merge_config.py
+++ b/examples/merge_config.py
@@ -1,5 +1,3 @@
-#!/usr/bin/env python3
-#
 # This script functions similarly to scripts/kconfig/merge_config.sh from the
 # kernel tree, merging multiple configurations fragments to produce a complete
 # .config, with unspecified values filled in as for alldefconfig.
@@ -37,7 +35,7 @@
 # conf3 contents:
 #
 #     # Ops... assigned twice
-#     CONFIG_FOO is not set
+#     # CONFIG_FOO is not set
 #
 #     Ops... this symbol doesn't exist
 #     CONFIG_OPS=y
@@ -52,13 +50,13 @@
 #
 # Running:
 #
-#     $ ./merge_config.py Kconfig merged conf1 conf2 conf3 conf4
-#     conf3:2: warning: FOO set more than once. Old value: "y", new value: "n".
+#     $ python(3) merge_config.py Kconfig merged conf1 conf2 conf3 conf4
+#     conf3:2: warning: FOO (defined at Kconfig:1) set more than once. Old value: "y", new value: "n".
 #     conf3:5: warning: attempt to assign the value "y" to the undefined symbol OPS
-#     warning: QAZ was assigned the value "y" but got the value "n" -- check dependencies
+#     warning: QAZ (defined at Kconfig:10) was assigned the value "y" but got the value "n" -- check dependencies
 #     $ cat merged
 #     Generated by Kconfiglib (https://github.com/ulfalizer/Kconfiglib)
-#     CONFIG_FOO is not set
+#     # CONFIG_FOO is not set
 #     CONFIG_BAR=y
 #     CONFIG_BAZ="baz string"
 from kconfiglib import Kconfig, Symbol, BOOL, TRISTATE, TRI_TO_STR
@@ -86,6 +84,21 @@ kconf.write_config(sys.argv[2])
 
 # Print warnings for symbols whose actual value doesn't match the assigned
 # value
+
+def name_and_loc_str(sym):
+    """
+    Helper for printing the symbol name along with the location(s) in the
+    Kconfig files where the symbol is defined
+    """
+    # If the symbol has no menu nodes, it is undefined
+    if not sym.nodes:
+        return sym.name + " (undefined)"
+
+    return "{} (defined at {})".format(
+        sym.name,
+        ", ".join("{}:{}".format(node.filename, node.linenr)
+                  for node in sym.nodes))
+
 for sym in kconf.defined_syms:
     # Was the symbol assigned to?
     if sym.user_value is not None:
@@ -99,4 +112,4 @@ for sym in kconf.defined_syms:
         if user_value != sym.str_value:
             print('warning: {} was assigned the value "{}" but got the '
                   'value "{}" -- check dependencies'
-                  .format(sym.name, user_value, sym.str_value))
+                  .format(name_and_loc_str(sym), user_value, sym.str_value))
diff --git a/examples/oldconfig.py b/examples/oldconfig.py
index aa8e253..737ddae 100644
--- a/examples/oldconfig.py
+++ b/examples/oldconfig.py
@@ -60,7 +60,7 @@
 #
 #     $ touch .config  # Run with empty .config
 #
-#     $ python oldconfig.py Kconfig
+#     $ python(3) oldconfig.py Kconfig
 #     BOOL_SYM prompt (BOOL_SYM, defined at Kconfig:5) [n/Y] foo
 #     Invalid tristate value
 #     BOOL_SYM prompt (BOOL_SYM, defined at Kconfig:5) [n/Y] n
@@ -118,7 +118,7 @@ def print_help(node):
 def name_and_loc_str(sym):
     """
     Helper for printing the symbol name along with the location(s) in the
-    Kconfig files where it is defined
+    Kconfig files where the symbol is defined
     """
     return "{}, defined at {}".format(
         sym.name,