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Postings from July 2016
Storable.xs:
/*
* The "magic number" is only for files, not when freezing in memory.
*/
a is decimal 97 is ascii. The first two bytes are interpreted as major.minor version, but the first byte is first rightshifted - apparently the least significant bit is used to encode something else.
So, "aa" actually survives partway through magic_check(), when Storable discovers that 48.97 is much too high a version. "a" is the unusual case, because there isn't a second byte to read:
if (version_major > 1)
GETMARK(version_minor);
And there is no character to be had, so it returns from magic_check without setting any other diagnostics.
In any event - there is no magic number that we can possibly check for thaw() from memory. The first two bytes are the version number. There are a number of different ways we can get weird error messages. So we should really just give a better error message in the cases that are most likely to be accidentally stumbled on.
I think that's the "version more recent" error as well as the "byte order not compatible" error (which you can get by passing in "\004\012\000xxxx"). Any other error message requires a crafted string like "\004\012\01012345678xxxx", which seems unlikely to happen by accident.
Will upload the patch momentarily.
---
via perlbug: queue: perl5 status: open
https://rt.perl.org/Ticket/Display.html?id=30807
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