bitbake: ConfHandler: Allow the '@' character in variable flag names

This patch enables the usage of the '@' character in variable flag
names.

One use case of variable flags is to assign the network namespaces of
some systemd services/targets to configure other parts of the build
process of some system. The filenames of systemd services/targets might
contain the '@' character if they are template unit files that can take
in a single parameter/argument and be instanced multiple times, as
indicated by systemd's official manual page.

The '@' character is disallowed as the first character in a variable
flag name. Imposing more restrictions on the first character is a
compromise to make parsing easier and to allow for more options in the
future to extend the syntax.

This patch is successfully verified by creating a custom BitBake recipe
that sets and unsets the value of a variable flag with the '@' character
in its name and ensuring that no ParseError is being thrown. Regression
tests have also been added to `bb.parse`.

`bin/bitbake-selftest` has also been successfully executed and all tests
passed.

(Bitbake rev: 00f9ab2cacfbd2a63b6b4959cf5401babae7e32a)

Signed-off-by: James Raphael Tiovalen <jamestiotio@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

0 files changed, 0 insertions, 0 deletions