Fix #309: Use stream_select instead of non-blocking STDIN #312
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The idiom used in the readStdin function from src/Utils/CLI.php is not entirely error-prone: marking stdin as non-blocking and then reading from it can lead to racy scenarios where we are not able to catch what's being fed to the program. This can be seen very frequently on s390x, where a loop like this: $ while echo "invalid query" | /usr/bin/php7.4 /path/to//highlight-query; do sleep 1; done; will lead to failures once on every few runs (as can be seen in the description of issue phpmyadmin#309). This commit implements the more robust method which uses stream_select to wait for stdin to become available, but resorts to a sensible timeout value (0.2 seconds) which will prevent the blocking from happening. I tested this patch extensively on s390x and amd64, and noticed that the non-determinism is gone. Signed-off-by: Sergio Durigan Junior <sergio.durigan@canonical.com>
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Signed-off-by: William Desportes <williamdes@wdes.fr>
Codecov Report
@@ Coverage Diff @@
## QA #312 +/- ##
============================================
+ Coverage 99.62% 99.73% +0.11%
- Complexity 1860 1899 +39
============================================
Files 63 63
Lines 4523 4581 +58
============================================
+ Hits 4506 4569 +63
+ Misses 17 12 -5
Continue to review full report at Codecov.
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The idiom used in the readStdin function from src/Utils/CLI.php is not
entirely error-prone: marking stdin as non-blocking and then reading
from it can lead to racy scenarios where we are not able to catch
what's being fed to the program. This can be seen very frequently on
s390x, where a loop like this:
$ while echo "invalid query" | /usr/bin/php7.4 /path/to//highlight-query; do sleep 1; done;
will lead to failures once on every few runs (as can be seen in the
description of issue #309).
This commit implements the more robust method which uses stream_select
to wait for stdin to become available, but resorts to a sensible
timeout value (0.2 seconds) which will prevent the blocking from
happening.
I tested this patch extensively on s390x and amd64, and noticed that
the non-determinism is gone.
Signed-off-by: Sergio Durigan Junior sergio.durigan@canonical.com