Bug#1064036: dpkg: wrong dpkg-query exit status on syntax error?
Hey Guillem. On Fri, 2024-02-16 at 05:26 +0100, Guillem Jover wrote: > > Thanks! Well rather: thank you, for your constant efforts to DPKG and the whole ecosystem. > > At least it seems to make it impossible to definitely find out > > whether a package > > is not installed (respectively not existant). > > Exactly. Maybe it would also be worth to elaborate on: 1 The requested query failed either fully or partially, due to no file or package being found (except for --control-path, --control-list and --control-show were such errors are fatal). My understanding would have been, that e.g. when searching for a package, 1 would in practise mean that it doesn't exist at all (when looking from APT’s PoV) respectively is in the state 'not-installed'. So I guess for end-users it might be helpful to be told that, i.e. that these two things (non-existing from APT) and non-installed are the same from DPKG’s PoV, and would trigger 1. Also perhaps notifying somewhere that 'not-installed' will never really show up anywhere as a printed query result. > This is used for field names, be them real or virtual, so erroring > out > on fields that do not exist would seem bad. But there's the > distinction between the real fields and virtual ones, where the > latter > always contain a colon. So I guess I could make the latter, at least > warn if they do not exist. My main concern with making them errors, > is > that this would break backwards and/or forwards compatibility, where > you could not use a new or renamed field with old or new releases. Warnings are at last difficult to use when scripting. And btw: it also succeeds if there's no colon, e.g.: $ dpkg-query --showformat='${foobar}' --show 2>/dev/null ; echo $? 0 Thanks, Chris. PS: In the dpkg-query manpage, there's: Desired action: u = Unknown i = Install h = Hold r = Remove p = Purge Package status: n = Not-installed c = Config-files H = Half-installed U = Unpacked F = Half-configured W = Triggers-awaiting t = Triggers-pending i = Installed Error flags: = (none) R = Reinst-required I think, when these are actually printed, the full names are all lowercase, i.e. installed not Installed ... might perhaps make sense to align that?
Bug#1064036: dpkg: wrong dpkg-query exit status on syntax error?
Hi! On Fri, 2024-02-16 at 04:37:47 +0100, Christoph Anton Mitterer wrote: > Package: dpkg > Version: 1.22.4 > Severity: normal > dpkg-query manpage says: > EXIT STATUS >0 The requested query was successfully performed. > >1 The requested query failed either fully or partially, due to no >file or package being found (except for --control-path, >--control-list and --control-show were such errors are fatal). > >2 Fatal or unrecoverable error due to invalid command-line usage, or >interactions with the system, such as accesses to the database, >memory allocations, etc. > E.g.: > $ dpkg-query --showformat='${db:Status-Status}' --show --list 2>/dev/null ; > echo $? > 2 > looks good, as does > $ dpkg-query --showformat='${db:Status-Status}' --show not-existing-package > 2>/dev/null ; echo $? > 1 > > But e.g. > $ dpkg-query --showformat='${db:Status-Statu' --show 2>/dev/null ; echo $? > 1 > causes also 1, though it fails because of the syntax error in the format > string. > > Shouldn't that be a 2? Yeah, I think so. I've looked into this now, and there are several problems in the dpkg-query code, one is that several of the action functions only ever return 1 for any direct failure they handle, the other is that even if they returned something else, the main() function coerces that return code into a boolean, so it always ends up being 0 or 1. I'll have a pass over the entire code, and correct all instances and queue this for the next upload. Thanks! > At least it seems to make it impossible to definitely find out whether a > package > is not installed (respectively not existant). Exactly. > btw. it will also not fail at all in cases like: > $ dpkg-query --showformat='${db:Status-Statu}' --show 2>/dev/null ; echo $? > 0 > where the field doesn't exist. Not sure whether that’s desired or not This is used for field names, be them real or virtual, so erroring out on fields that do not exist would seem bad. But there's the distinction between the real fields and virtual ones, where the latter always contain a colon. So I guess I could make the latter, at least warn if they do not exist. My main concern with making them errors, is that this would break backwards and/or forwards compatibility, where you could not use a new or renamed field with old or new releases. Thanks, Guillem
Bug#1064036: dpkg: wrong dpkg-query exit status on syntax error?
Package: dpkg Version: 1.22.4 Severity: normal Hey. dpkg-query manpage says: EXIT STATUS 0 The requested query was successfully performed. 1 The requested query failed either fully or partially, due to no file or package being found (except for --control-path, --control-list and --control-show were such errors are fatal). 2 Fatal or unrecoverable error due to invalid command-line usage, or interactions with the system, such as accesses to the database, memory allocations, etc. E.g.: $ dpkg-query --showformat='${db:Status-Status}' --show --list 2>/dev/null ; echo $? 2 looks good, as does $ dpkg-query --showformat='${db:Status-Status}' --show not-existing-package 2>/dev/null ; echo $? 1 But e.g. $ dpkg-query --showformat='${db:Status-Statu' --show 2>/dev/null ; echo $? 1 causes also 1, though it fails because of the syntax error in the format string. Shouldn't that be a 2? At least it seems to make it impossible to definitely find out whether a package is not installed (respectively not existant). btw. it will also not fail at all in cases like: $ dpkg-query --showformat='${db:Status-Statu}' --show 2>/dev/null ; echo $? 0 where the field doesn't exist. Not sure whether that’s desired or not Cheers, Chris. -- Package-specific info: -- System Information: Debian Release: trixie/sid APT prefers unstable-debug APT policy: (500, 'unstable-debug'), (500, 'unstable') Architecture: amd64 (x86_64) Kernel: Linux 6.6.15-amd64 (SMP w/16 CPU threads; PREEMPT) Locale: LANG=en_DE.UTF-8, LC_CTYPE=en_DE.UTF-8 (charmap=UTF-8), LANGUAGE not set Shell: /bin/sh linked to /usr/bin/dash Init: systemd (via /run/systemd/system) Versions of packages dpkg depends on: ii libbz2-1.0 1.0.8-5+b2 ii libc62.37-15 ii liblzma5 5.4.5-0.3 ii libmd0 1.1.0-2 ii libselinux1 3.5-2 ii libzstd1 1.5.5+dfsg2-2 ii tar 1.35+dfsg-3 ii zlib1g 1:1.3.dfsg-3+b1 dpkg recommends no packages. Versions of packages dpkg suggests: ii apt2.7.11 ii debsig-verify 0.29 -- no debconf information