Commit f8c56f5f authored by Thomas De Schampheleire's avatar Thomas De Schampheleire Committed by Peter Korsgaard
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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: default avatarThomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Acked-by: default avatarArnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: default avatarPeter Korsgaard <peter@korsgaard.com>
parent 0764b1cf

Config.in.legacy

+43 −7
Original line number Diff line number Diff line 
#

# 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