[Scons-users] Possible bug with cache and Value()

[Bill Deegan]

Try changing the following:
SCons/Node/Python.py around line 139:

def get_contents(self):
text_contents = self.get_text_contents()
try:
return text_contents
except UnicodeDecodeError:
# Already encoded as python2 str are bytes
return text_contents



The return text_contents is orignally test_contents.encode(), which changes
it to bytes.
Then later the code tries to join a str space with a byte string and
crashes.

I'm going to say this is not actually correct for python 3, but it will
work and shouldn't have any issues.
The reason I'm saying it's not correct is because I think all signitures
should be bytes and not strings.
For py2.7 it doesn't matter.
For Py 3.5+ I shouldn't matter, but I'm trying to keep all signatures as
bytes and be calculated that way.  In the case that the Value() node had a
byte string value which wasn't encodable as a unicode string I would expect
it to break (read stack trace).


Thoughts?

-Bill


On Wed, Nov 22, 2017 at 7:18 AM, Bill Deegan <bill at baddogconsulting.com>
wrote:
>
> Rob,
>
> At first glance looks like a bug on a code path which must not be covered
by our tests.
> string vs bytes is a dead giveaway.
>
> You must be running scons 3.0.1 with python 3.5+?
> Can you try running with python 2.7.x? (It should work)
>
> -Bill
>
> On Wed, Nov 22, 2017 at 3:36 AM, Rob Spanton <rob at robspanton.com> wrote:
>>
>> Hi,
>>
>> I recently upgraded to scons 3.0.1, and I'm encountering a problem with
using
>> CacheDir() in combination with Value().  I can replicate the issue with
this
>> minimal SConstruct:
>>
>>     CacheDir("cache")
>>     Command("somefile", Value("test"), "echo hi > $TARGET")
>>
>>     I've included the traceback that this produces at the end of this
email.  I
>>     think what I'm doing with CacheDir, Command and Value is legitimate
but am
>>     entirely happy to be persuaded that it is not!
>>
>>     I can work with this for the moment by disabling the cache, but it
would be
>>     useful if someone with some more in-depth scons knowledge than me
could shed
>>     some light on what's going on.
>>
>>     Thanks,
>>
>>     Rob Spanton
>>
>>     ---
>>
>>     scons: Reading SConscript files ...
>>     scons: done reading SConscript files.
>>     scons: Building targets ...
>>     scons: *** [somefile] TypeError : sequence item 0: expected str
instance, bytes found
>>     Traceback (most recent call last):
>>       File "/usr/lib/scons/SCons/Action.py", line 689, in __call__
>>         cmd = self.strfunction(target, source, env, executor)
>>     TypeError: CacheRetrieveString() takes 3 positional arguments but 4
were given
>>
>>     During handling of the above exception, another exception occurred:
>>
>>     Traceback (most recent call last):
>>       File "/usr/lib/scons/SCons/Taskmaster.py", line 241, in execute
>>         if not t.retrieve_from_cache():
>>       File "/usr/lib/scons/SCons/Node/FS.py", line 2925, in
retrieve_from_cache
>>         return self.get_build_env().get_CacheDir().retrieve(self)
>>       File "/usr/lib/scons/SCons/CacheDir.py", line 263, in retrieve
>>         if CacheRetrieve(node, [], env, execute=1) == 0:
>>       File "/usr/lib/scons/SCons/Action.py", line 691, in __call__
>>         cmd = self.strfunction(target, source, env)
>>       File "/usr/lib/scons/SCons/CacheDir.py", line 66, in
CacheRetrieveString
>>         cachedir, cachefile = cd.cachepath(t)
>>       File "/usr/lib/scons/SCons/CacheDir.py", line 224, in cachepath
>>         sig = node.get_cachedir_bsig()
>>       File "/usr/lib/scons/SCons/Node/FS.py", line 3391, in
get_cachedir_bsig
>>         result = self.cachesig = SCons.Util.MD5collect(sigs)
>>       File "/usr/lib/scons/SCons/Util.py", line 1550, in MD5collect
>>         return MD5signature(', '.join(signatures))
>>     TypeError: sequence item 0: expected str instance, bytes found
>>     scons: building terminated because of errors.
>> _______________________________________________
>> Scons-users mailing list
>> Scons-users at scons.org
>> https://pairlist4.pair.net/mailman/listinfo/scons-users
>
>
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