Add merge_config.py example

Functions similarly to scripts/kconfig/merge_config.sh from the kernel.

Came up in https://github.com/zephyrproject-rtos/zephyr/pull/5417.

1 files changed, 102 insertions, 0 deletions

diff --git a/examples/merge_config.py b/examples/merge_config.py
new file mode 100644
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+++ b/examples/merge_config.py
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+#!/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.
+#
+# The generated .config respects symbol dependencies, and a warning is printed
+# if any symbol gets a different value from the assigned value.
+#
+# Here's a demo:
+#
+# Kconfig contents:
+#
+#     config FOO
+#         bool "FOO"
+#
+#     config BAR
+#         bool "BAR"
+#
+#     config BAZ
+#         string "BAZ"
+#
+#     config QAZ
+#         bool "QAZ" if n
+#
+#
+# conf1 contents:
+#
+#     CONFIG_FOO=y
+#
+#
+# conf2 contents:
+#
+#     CONFIG_BAR=y
+#
+#
+# conf3 contents:
+#
+#     # Ops... assigned twice
+#     CONFIG_FOO is not set
+#
+#     Ops... this symbol doesn't exist
+#     CONFIG_OPS=y
+#
+#     CONFIG_BAZ="baz string"
+#
+#
+# conf4 contents:
+#
+#     CONFIG_QAZ=y
+#
+#
+# Running:
+#
+#     $ ./merge_config.py Kconfig merged conf1 conf2 conf3 conf4
+#     conf3:2: warning: FOO 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
+#     $ cat merged
+#     Generated by Kconfiglib (https://github.com/ulfalizer/Kconfiglib)
+#     CONFIG_FOO is not set
+#     CONFIG_BAR=y
+#     CONFIG_BAZ="baz string"
+from kconfiglib import Kconfig, Symbol, BOOL, TRISTATE, TRI_TO_STR
+import sys
+
+if len(sys.argv) < 4:
+    print("usage: merge_config.py Kconfig merged_config config1 [config2 ...]")
+    sys.exit(1)
+
+kconf = Kconfig(sys.argv[1])
+
+# Enable warnings for assignments to undefined symbols
+kconf.enable_undef_warnings()
+
+# (This script uses alldefconfig as the base. Other starting states could be
+# set up here as well. The approach in examples/allnoconfig_simpler.py could
+# provide an allnoconfig starting state for example.)
+
+# Create a merged configuration by loading the fragments with replace=False
+for config in sys.argv[3:]:
+    kconf.load_config(config, replace=False)
+
+# Write the merged configuration
+kconf.write_config(sys.argv[2])
+
+# Print warnings for symbols whose actual value doesn't match the assigned
+# value
+for sym in kconf.defined_syms:
+    # Was the symbol assigned to?
+    if sym.user_value is not None:
+        # Tristate values are represented as 0, 1, 2. Having them as
+        # "n", "m", "y" is more convenient here, so convert.
+        if sym.type in (BOOL, TRISTATE):
+            user_value = TRI_TO_STR[sym.user_value]
+        else:
+            user_value = sym.user_value
+
+        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))