On 06-03-15 10:35, Robert P. J. Day wrote:
On Fri, 6 Mar 2015, Mike Looijmans wrote:
On 05-03-15 09:43, Robert P. J. Day wrote:
a style guide thing ... it appears that COMPATIBLE_MACHINE happily
acccepts a matching RE within parentheses or not, is there a
preference?
also, in checking that, i ran across this in oe-core:
linux-yocto_3.14.bb:COMPATIBLE_MACHINE =
"qemuarm|qemuarm64|qemux86|qemuppc|qemumips|qemumips64|qemux86-64"
linux-yocto_3.19.bb:COMPATIBLE_MACHINE =
"qemuarm|qemuarm64|qemux86|qemuppc|qemumips|qemumips64|qemux86-64"
linux-yocto-dev.bb:COMPATIBLE_MACHINE =
"(qemuarm|qemux86|qemuppc|qemumips|qemumips64|qemux86-64)"
The regex should have been "qemu(arm|x86|ppc|mips|mips64|x86-64)"
And since "x86-64" already matches "x86", that could have been omitted.
where the first two recipes list "qemuarm64" but the dev version
doesn't ... is that deliberate?
Probably not, but "qemuarm64" matches "qemuarm" already.
more nitpcking pedantry, but as i read it from the python code in
base.bbclass:
need_machine = d.getVar('COMPATIBLE_MACHINE', True)
if need_machine:
import re
compat_machines = (d.getVar('MACHINEOVERRIDES', True) or
"").split(":")
for m in compat_machines:
if re.match(need_machine, m):
break
the "re.match"ing does not implicitly anchor the RE to the beginning
or end of string, correct? it couldn't, or "qemuarm64" could not
possibly match "qemuarm".
does that not suggest that one should add those anchors to avoid the
(admittedly unlikely) situation where i define a machine named, say,
"rdayqemux86" which, as i read it, will match a "qemux86" machine even
if i didn't want it to? would i then avoid this by setting:
COMPATIBLE_MACHINE = "^rdayqemu"
to match *all* machines whose names *start* with "rdayqemu"? this
really isn't explained carefully anywhere i can see.
Well, I got my knowledge the hard way too (getting hit with unexpected results
and then looking into the source code).
Without further hints, I think over 90% of the users think that
COMPATIBLE_MACHINE does an exact match, not a regex match, and when they see
the "|" in some recipes, they just assume some code will do a
string.split('|') on it.
I wonder if the actual intention of that long qemu mach was "all QEMU
machines", in which case the expression could have been simply "qemu" or
better "^qemu".
Met vriendelijke groet / kind regards,
Mike Looijmans
System Expert
TOPIC Embedded Systems
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