| Message ID | 20210701095635.15648-7-olaf@aepfle.de (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | leftover from 2020 | expand |
On Thu, Jul 01, 2021 at 11:56:01AM +0200, Olaf Hering wrote: > Using the first element of a tuple for a format specifier fails with > python3.4 as included in SLE12: > b = b"string/%x" % (i, ) > TypeError: unsupported operand type(s) for %: 'bytes' and 'tuple' > > It happens to work with python 2.7 and 3.6. > Use a syntax that is handled by all three variants. > > Signed-off-by: Olaf Hering <olaf@aepfle.de> > --- > tools/python/scripts/convert-legacy-stream | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/tools/python/scripts/convert-legacy-stream b/tools/python/scripts/convert-legacy-stream > index 9003ac4f6d..235b922ff5 100755 > --- a/tools/python/scripts/convert-legacy-stream > +++ b/tools/python/scripts/convert-legacy-stream > @@ -347,9 +347,9 @@ def read_libxl_toolstack(vm, data): > if nil != 0: > raise StreamError("physmap name not NUL terminated") > > - root = b"physmap/%x" % (phys, ) > - kv = [root + b"/start_addr", b"%x" % (start, ), > - root + b"/size", b"%x" % (size, ), > + root = bytes(("physmap/%x" % phys).encode('utf-8')) > + kv = [root + b"/start_addr", bytes(("%x" % start).encode('utf-8')), > + root + b"/size", bytes(("%x" % size).encode('utf-8')), Why bytes()? Encode does already return bytes type. > root + b"/name", name] > > for key, val in zip(kv[0::2], kv[1::2]):
On 02/07/2021 17:19, Marek Marczykowski-Górecki wrote: > On Thu, Jul 01, 2021 at 11:56:01AM +0200, Olaf Hering wrote: >> Using the first element of a tuple for a format specifier fails with >> python3.4 as included in SLE12: >> b = b"string/%x" % (i, ) >> TypeError: unsupported operand type(s) for %: 'bytes' and 'tuple' >> >> It happens to work with python 2.7 and 3.6. >> Use a syntax that is handled by all three variants. >> >> Signed-off-by: Olaf Hering <olaf@aepfle.de> >> --- >> tools/python/scripts/convert-legacy-stream | 6 +++--- >> 1 file changed, 3 insertions(+), 3 deletions(-) >> >> diff --git a/tools/python/scripts/convert-legacy-stream b/tools/python/scripts/convert-legacy-stream >> index 9003ac4f6d..235b922ff5 100755 >> --- a/tools/python/scripts/convert-legacy-stream >> +++ b/tools/python/scripts/convert-legacy-stream >> @@ -347,9 +347,9 @@ def read_libxl_toolstack(vm, data): >> if nil != 0: >> raise StreamError("physmap name not NUL terminated") >> >> - root = b"physmap/%x" % (phys, ) >> - kv = [root + b"/start_addr", b"%x" % (start, ), >> - root + b"/size", b"%x" % (size, ), >> + root = bytes(("physmap/%x" % phys).encode('utf-8')) >> + kv = [root + b"/start_addr", bytes(("%x" % start).encode('utf-8')), >> + root + b"/size", bytes(("%x" % size).encode('utf-8')), > Why bytes()? Encode does already return bytes type. Yes - I've just tried this out on various version of python (including https://www.onlinegdb.com/online_python_interpreter which is the only place I can find Python 3.4 easily available) .encode() does return bytes (Py3) or str (Py2) so doesn't need the surrounding bytes(). However, the % (phys, ) with the trailing comma is deliberate to work around a common python error, so wants to remain if you're keeping the %-formatting. ~Andrew
Am Fri, 2 Jul 2021 18:19:39 +0200
schrieb Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>:
> Why bytes()? Encode does already return bytes type.
You are right, this works as well:
i = 123
b = ("str/%x" % (i, )).encode('utf-8')
Any preference regarding the "encoding"? I picked UTF8, but 'ascii' might be more correct in this context. In practice it may not matter.
Olaf
Am Fri, 2 Jul 2021 17:39:54 +0100 schrieb Andrew Cooper <andrew.cooper3@citrix.com>: > However, the % (phys, ) with the trailing comma is deliberate to work > around a common python error, so wants to remain if you're keeping the > %-formatting. What error is that? Olaf
On 05/07/2021 09:18, Olaf Hering wrote: > Am Fri, 2 Jul 2021 17:39:54 +0100 > schrieb Andrew Cooper <andrew.cooper3@citrix.com>: > >> However, the % (phys, ) with the trailing comma is deliberate to work >> around a common python error, so wants to remain if you're keeping the >> %-formatting. > What error is that? >>> def p1(arg): ... print("%s" % arg) >>> def p2(arg): ... print("%s" % (arg, )) >>> p1("foo") foo >>> p2("foo") foo >>> p1(("foo", "bar")) Traceback (most recent call last): File "<stdin>", line 1, in <module> File "<stdin>", line 2, in p1 TypeError: not all arguments converted during string formatting >>> p2(("foo", "bar")) ('foo', 'bar') The % operator has some type ambiguity with how it works. (foo, ) forces arg to be a 1-tuple as far as formatting is concerned. ~Andrew
On 05/07/2021 09:07, Olaf Hering wrote: > Am Fri, 2 Jul 2021 18:19:39 +0200 > schrieb Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>: > >> Why bytes()? Encode does already return bytes type. > You are right, this works as well: > i = 123 > b = ("str/%x" % (i, )).encode('utf-8') > > Any preference regarding the "encoding"? I picked UTF8, but 'ascii' might be more correct in this context. In practice it may not matter. I suspect you're right and it doesn't matter, but ascii feels like a safer option. ~Andrew
diff --git a/tools/python/scripts/convert-legacy-stream b/tools/python/scripts/convert-legacy-stream index 9003ac4f6d..235b922ff5 100755 --- a/tools/python/scripts/convert-legacy-stream +++ b/tools/python/scripts/convert-legacy-stream @@ -347,9 +347,9 @@ def read_libxl_toolstack(vm, data): if nil != 0: raise StreamError("physmap name not NUL terminated") - root = b"physmap/%x" % (phys, ) - kv = [root + b"/start_addr", b"%x" % (start, ), - root + b"/size", b"%x" % (size, ), + root = bytes(("physmap/%x" % phys).encode('utf-8')) + kv = [root + b"/start_addr", bytes(("%x" % start).encode('utf-8')), + root + b"/size", bytes(("%x" % size).encode('utf-8')), root + b"/name", name] for key, val in zip(kv[0::2], kv[1::2]):
Using the first element of a tuple for a format specifier fails with python3.4 as included in SLE12: b = b"string/%x" % (i, ) TypeError: unsupported operand type(s) for %: 'bytes' and 'tuple' It happens to work with python 2.7 and 3.6. Use a syntax that is handled by all three variants. Signed-off-by: Olaf Hering <olaf@aepfle.de> --- tools/python/scripts/convert-legacy-stream | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)