Issue catching KeyboardInterrupt while reading stdin

[JoshHanson]

BPO	10837
Nosy	@tjguk, @ssbr, @iritkatriel

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2020-11-30.13:39:56.408>
created_at = <Date 2011-01-05.20:02:04.675>
labels = ['type-bug', 'expert-IO', 'OS-windows']
title = 'Issue catching KeyboardInterrupt while reading stdin'
updated_at = <Date 2020-11-30.13:39:56.407>
user = 'https://bugs.python.org/JoshHanson'

bugs.python.org fields:

activity = <Date 2020-11-30.13:39:56.407>
actor = 'iritkatriel'
assignee = 'none'
closed = True
closed_date = <Date 2020-11-30.13:39:56.408>
closer = 'iritkatriel'
components = ['Windows', 'IO']
creation = <Date 2011-01-05.20:02:04.675>
creator = 'Josh.Hanson'
dependencies = []
files = []
hgrepos = []
issue_num = 10837
keywords = []
message_count = 5.0
messages = ['125463', '131629', '131630', '222888', '382148']
nosy_count = 4.0
nosy_names = ['tim.golden', 'Devin Jeanpierre', 'Josh.Hanson', 'iritkatriel']
pr_nums = []
priority = 'normal'
resolution = 'out of date'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue10837'
versions = ['Python 2.7']

[JoshHanson]

Example code:
try:
sys.stdin.read()
except KeyboardInterrupt:
print "Interrupted!"
except:
print "Some other exception?"
finally:
print "cleaning up..."
print "done."

Test: run the code and hit ctrl-c while the read is blocking.
Expected behavior: program should print:
Interrupted!
cleaning up...
done.

Actual behavior: On linux, behaves as expected. On windows, prints:
    cleaning up... 
    Traceback (most recent call last):
      File "filename.py", line 119, in <module>
        print 'cleaning up...'
    KeyboardInterrupt

As you can see, neither of the "except" blocks was executed, and the "finally" block was erroneously interrupted.

If I add one line inside the try block, as follows:
try:
sys.stdin.read()
print "Done reading."
... [etc.]

Then this is the output:
Done reading. Interrupted!
cleaning up...
done.

Here, the exception handler and finally block were executed as expected. This is still mildly unusual because the "done reading" print statement was reached when it probably shouldn't have been, but much more surprising because a newline was not printed after "Done reading.", and for some reason a space was.

This has been tested and found in 32-bit python versions 2.6.5, 2.6.6, 2.7.1, and 3.1.3 on 64-bit Win7.

[ssbr]

I can confirm this behavior on 2.7. On 3.2 for me it prints "done.", but not "Interrupted!"

[ssbr]

Sorry, forgot to mention my system. 64-bit Windows 7.

[BreamoreBoy]

I can confirm that this works fine with 3.4.1 and 3.5.0a0. I don't run 2.7 any more so I don't know if this is fixed in later versions.

[iritkatriel]

Python 2-only issue.