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authorThomas De Schampheleire <patrickdepinguin+buildroot@gmail.com>2013-09-02 20:07:50 (GMT)
committer Peter Korsgaard <peter@korsgaard.com>2013-10-26 17:04:30 (GMT)
commitf8c56f5f6298a31a5440f9ad50d36e4d09b5e0c9 (patch)
tree4b08f27948fc90804e39fb4b36e7b221e98f1914
parent0764b1cf4573f7fdae9faa280898a7a9950da100 (diff)
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Config.in.legacy: update description for developers
The existing comments in Config.in.legacy are not entirely in-line with current practice. The comments implies that BR2_LEGACY should not be set when the conversion from old-to-new symbol can be done automatically using the appropriate 'select' statements. However, none of the existing legacy options does it this way. Moreover, I think it's intentional that the user is notified of the change, so that the removal of the legacy options in later buildroot versions no longer poses a problem. Additionally, the comments now describe how to handle string options. Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com> Acked-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be> Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
-rw-r--r--Config.in.legacy50
1 files changed, 43 insertions, 7 deletions
diff --git a/Config.in.legacy b/Config.in.legacy
index 4f30b2b..18224a0 100644
--- a/Config.in.legacy
+++ b/Config.in.legacy
@@ -1,13 +1,9 @@
#
# Config.in.legacy - support for backward compatibility
#
-# When an existing Config.in symbol is removed, it should be added again in this
-# file, and take appropriate action to approximate backward compatibility. If
-# there is an equivalent (set of) new symbols, these can just be select'ed by
-# the old symbol. This makes sure that running 'make oldconfig' will make things
-# "just work" when upgrading to a new buildroot version. If the change is too
-# fundamental and cannot be fixed by a simple select, then the old symbol should
-# select BR2_LEGACY. If that symbol is set, the build will issue an error.
+# When an existing Config.in symbol is removed, it should be added again in
+# this file, and take appropriate action to approximate backward compatibility.
+# This will make the transition for the user more convenient.
#
# When adding legacy symbols to this file, add them to the front. The oldest
# symbols will be removed again after about two years.
@@ -15,6 +11,46 @@
# The symbol should be copied as-is from the place where it was previously
# defined, but the help text should be removed or replaced with something that
# explains how to fix it.
+#
+# For bool options, the old symbol should select BR2_LEGACY, so that the user
+# is informed at build-time about selected legacy options.
+# If there is an equivalent (set of) new symbols, these should be select'ed by
+# the old symbol for backwards compatibility.
+#
+# For string options, it is not possible to directly select another symbol. In
+# this case, a hidden wrap bool option has to be added, that defaults to y if
+# the old string is not set at its default value. The wrap symbol should select
+# BR2_LEGACY.
+# If the original symbol has been renamed, the new symbol should use the value
+# of the old symbol as default. This requires a change outside of
+# Config.in.legacy, and this should be clearly marked as such below, so that
+# removal of legacy options also include the removal of these external
+# references.
+#
+# [Example: renaming a string option from FOO to BAR]
+# original symbol:
+# config BR2_FOO_STRING
+# string "Some foo string"
+#
+# becomes:
+# config BR2_BAR_STRING
+# string "Some bar string"
+# default BR2_FOO_STRING if BR2_FOO_STRING != "" # legacy
+#
+# and in Config.in.legacy:
+# config BR2_FOO_STRING
+# string "The foo string has been renamed"
+# help
+# <suitable help text>
+#
+# config BR2_FOO_STRING_WRAP
+# bool
+# default y if BR2_FOO_STRING != ""
+# select BR2_LEGACY
+#
+# # Note: BR2_FOO_STRING is still referenced from package/foo/Config.in
+#
+# [End of example]
config BR2_LEGACY
bool