Re: [Qemu-devel] [PATCH v2 0/5] qemu-io: Exit with error when a command failed

[Max Reitz <mreitz@redhat.com>]

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On 2018-05-09 21:42, Max Reitz wrote:
> Right now, qemu-io's exit code is rather useless as it is usually 0.
> Except sometimes, then it's 1 in case of an error (mostly when you
> specify a filename as an argument and it cannot open that).
> 
> At the same time, most command functions' return values are rather
> useless as they are usually 0 (meaning "continue execution").  There is
> only a single function that breaks that pattern, which is "quit".  On
> one hand, this is pointless because "quit" is in qemu-io.c, so it can
> easily signal that fact through a global (yet static) variable.  On the
> other, it breaks the usual pattern of I/O functions returning error
> codes.
> 
> This series resolves the overlap between both issues by making the
> command functions' return error values instead of whether to continue
> execution or not, and thus makes qemu-io return 1 if any of the commands
> executed has failed and 0 only if all of them have succeeded.
> 
> Patch 5 showcases how that may be useful for iotests.
> 
> 
> See also: https://bugzilla.redhat.com/show_bug.cgi?id=1519617
> 
> 
> v2:
> - Patch 2: Added a comment on the interface of command functions (their
>            parameters and their return value) [Eric]
> - (Decided against replacing 0/1 by EXIT_SUCCESS/EXIT_FAILURE, because
>    although I personally would prefer them slightly, neither are ever
>    used in qemu-io so far.)
> 
> git-backport-diff against v1:
> 
> Key:
> [----] : patches are identical
> [####] : number of functional differences between upstream/downstream patch
> [down] : patch is downstream-only
> The flags [FC] indicate (F)unctional and (C)ontextual differences, respectively
> 
> 001/5:[----] [-C] 'qemu-io: Drop command functions' return values'
> 002/5:[0005] [FC] 'qemu-io: Let command functions return error code'
> 003/5:[----] [--] 'qemu-io: Exit with error when a command failed'
> 004/5:[----] [--] 'iotests.py: Add qemu_io_silent'
> 005/5:[----] [-C] 'iotests: Let 216 make use of qemu-io's exit code'
> 
> 
> Max Reitz (5):
>   qemu-io: Drop command functions' return values
>   qemu-io: Let command functions return error code
>   qemu-io: Exit with error when a command failed
>   iotests.py: Add qemu_io_silent
>   iotests: Let 216 make use of qemu-io's exit code
> 
>  include/qemu-io.h             |   9 +-
>  qemu-io-cmds.c                | 276 ++++++++++++++++++++++++------------------
>  qemu-io.c                     |  62 +++++++---
>  tests/qemu-iotests/216        |  23 ++--
>  tests/qemu-iotests/216.out    |  17 +--
>  tests/qemu-iotests/iotests.py |   9 ++
>  6 files changed, 231 insertions(+), 165 deletions(-)

Applied to my block branch.

Max


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