Pickle `FLOAT` opcode inconsistency with whitespace

Bug report

Bug description:

A lot of Python code tolerates leading and trailing whitespace in string-to-number conversions. However, in the FLOAT opcode of pickle, the Python implementation can tolerate leading/trailing whitespace, while the C implementation throws an error and can't convert it. Note that the INT opcode can gracefully handle leading/trailing whitespace (in both Python and C).

Payloads:

payload:      b'F 5\n.'

pickle:       5.0
_pickle.c:    FAILURE could not convert string to float: ' 5
'
pickletools:
    0: F    FLOAT      5.0
    4: .    STOP
highest protocol among opcodes = 0

payload:      b'F5 \n.'

pickle:       5.0
_pickle.c:    FAILURE could not convert string to float
pickletools:
    0: F    FLOAT      5.0
    4: .    STOP
highest protocol among opcodes = 0

payload:      b'I 5 \n.'

pickle:       5
_pickle.c:    5
pickletools:  
    0: I    INT        5
    5: .    STOP
highest protocol among opcodes = 0

CPython versions tested on:

3.13

Operating systems tested on:

Linux

Linked PRs

• gh-135619

Beginne damit, die Python- und C-Implementierungen von pickles FLOAT-Opcode zu lokalisieren und ihren Umgang mit den bereitgestellten Payloads zu vergleichen. Führe die Beispiele unter Python 3.13 aus und überprüfe anschließend, dass führender und nachgestellter Whitespace in beiden Implementierungen konsistent behandelt werden.