Your message dated Mon, 10 Feb 2020 17:14:44 -0500
with message-id <[email protected]>
and subject line Re: Bug#950894: Acknowledgement (mawk: numeric comparison on
'sub()' resulted ${n} vars does not work properly)
has caused the Debian Bug report #950894,
regarding mawk: numeric comparison on 'sub()' resulted ${n} vars does not work
properly
to be marked as done.
This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.
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--
950894: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=950894
Debian Bug Tracking System
Contact [email protected] with problems
--- Begin Message ---
Package: mawk
Version: 1.3.3-17+b3
Severity: normal
Dear Maintainer,
NOTE: this affects both 'mawk' and 'gawk' equally, so i'm not sure if this is
some utterly esoteric behavior i'm just not "getting", but my expectations are
definitely not being met.
(i also am unaware if a bug can be co-assigned to different packages)
Attempting to do a search for filesystems > 90% inode % or size % was giving
anomolous results. (hair-pulling time)
I was using 'sub("%","",$1) to strip the % symbol off the results from:
df --output=ipcent,pcent,target /var /var/log
e.g.:
$ df --output=ipcent,pcent,target -t ext4 | mawk
'NR>1{sub("%","",$1);sub("%","",$2); if (($1>30)||($2>30)) print}'
40 79 /
6 30 /var
1 7 /opt
20 78 /home
1 89 /d1
(clearly /opt doesn't meet the reporting criteria)
I narrowed this down to what appears to be a field-size truncation comparison
issue with the result from the sub() against the comparison numeric on the
right-side of the relop:
# The following all work as expected: (no output)
$ for i in $(seq 20 29); do echo "$i%" | mawk '{if (int($1)>100) print}'; done
$ for i in $(seq 20 29); do echo "$i%" | gawk '{if (int($1)>100) print}'; done
$ for i in $(seq 20 29); do echo "$i%" | mawk '{if (($1+0)>100) print}'; done
$ for i in $(seq 20 29); do echo "$i%" | gawk '{if (($1+0)>100) print}'; done
This does NOT work, though it should: (none of these values should print, they
are all < 100, which is the comparison being made)
$ for i in $(seq 20 29); do echo "$i%" | mawk '{sub("%","",$1);if ($1>100)
printf("[%s][%d]\n",$1,$1)}'; done
[20][20]
[21][21]
[22][22]
[23][23]
[24][24]
[25][25]
[26][26]
[27][27]
[28][28]
[29][29]
The man pages clearly state that a dual-type (numeric&string) variable SHOULD
be implicitly cast to numeric if a comparison is against a numeric.
I also did this against a single digit input and a two-digit RHS value, and it
shows the same issue, where only the same number of digits of the RHS that the
input value contain are being compared.
$ for i in $(seq 0 20); do echo "$i%" | gawk '{sub("%","",$1);if ($1>40)
printf("[%s][%d]\n",$1,$1)}'; done
[5][5]
[6][6]
[7][7]
[8][8]
[9][9]
Using an RHS of a float also fails:
$ for i in $(seq 0 20); do echo "$i%" | gawk '{sub("%","",$1);if ($1>40.0)
printf("[%s][%d]\n",$1,$1)}'; done
[5][5]
[6][6]
[7][7]
[8][8]
[9][9]
I don't know how if there's a way to evaluate the internal data-type
representation for $1 here, so i printed it with printf both as string and
integer, and they report identical.
Thanks,
--stephen
-- System Information:
Debian Release: 10.2
APT prefers stable-updates
APT policy: (500, 'stable-updates'), (500, 'proposed-updates'), (500,
'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386
Kernel: Linux 4.19.0-7-amd64 (SMP w/16 CPU cores)
Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_OOT_MODULE,
TAINT_UNSIGNED_MODULE
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=
(charmap=UTF-8)
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
Versions of packages mawk depends on:
ii libc6 2.28-10
mawk recommends no packages.
mawk suggests no packages.
-- no debconf information
--- End Message ---
--- Begin Message ---
Version: 1.3.3-17
On Sat, 8 Feb 2020 12:33:20 -0700 Stephen Dowdy <[email protected]> wrote:
> Considered this closed. Communication on '[email protected]' indicates that
'sub()' modifies a 'strnum' to a 'string' for $1, and that it is no longer
considered "user input", but a string constant, and thus comparisons will be
done as string only.
>
> Ref: https://www.gnu.org/software/gawk/manual/html_node/Variable-Typing.html
Closing the bug per the bug submitter's request.
--
Thanks,
Boyuan Yang
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