Bug 734259 - repoquery should remove trailing newline from --qf for RPM compatibility
Summary: repoquery should remove trailing newline from --qf for RPM compatibility
Keywords:
Status: CLOSED WONTFIX
Alias: None
Product: Fedora
Classification: Fedora
Component: yum-utils
Version: 15
Hardware: Unspecified
OS: Unspecified
unspecified
low
Target Milestone: ---
Assignee: Seth Vidal
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2011-08-29 22:06 UTC by Matt McCutchen
Modified: 2014-01-21 23:19 UTC (History)
4 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2012-08-07 20:04:34 UTC
Type: ---
Embargoed:


Attachments (Terms of Use)
Fix (599 bytes, patch)
2011-08-29 22:06 UTC, Matt McCutchen
no flags Details | Diff

Description Matt McCutchen 2011-08-29 22:06:35 UTC
Created attachment 520474 [details]
Fix

Description of problem:
rpm uses the query format exactly as given, while repoquery adds a trailing newline after each package (the "print" statements in runQuery).  Thus, an RPM user who passes a query format ending in \n to repoquery will get extra blank lines.  repoquery should compensate by removing a trailing newline from the specified query format.  Alternatively, it could stop adding the trailing newline, but this would require larger code changes and break existing users who had gotten away without specifying a trailing newline.

Version-Release number of selected component (if applicable):
yum-utils-1.1.31-2.fc15

How reproducible:
Always

Steps to Reproduce:
1. repoquery -qa --qf '%{NAME}\n' 'yum-plugin-*'
  
Actual results (with showdupesfromrepos on):
yum-plugin-aliases

yum-plugin-aliases

yum-plugin-aliases

yum-plugin-auto-update-debug-info

yum-plugin-auto-update-debug-info

yum-plugin-auto-update-debug-info
[...]

Expected results:
yum-plugin-aliases
yum-plugin-aliases
yum-plugin-aliases
yum-plugin-auto-update-debug-info
yum-plugin-auto-update-debug-info
yum-plugin-auto-update-debug-info
[...]

Comment 1 seth vidal 2011-08-30 03:44:53 UTC
We were asked about this before and the answer then is the same as now.

No.

Just b/c rpm made some bad choices a long time ago is no reason to continue it in repoquery now.

Comment 2 Matt McCutchen 2011-08-30 03:55:46 UTC
I see the previous bugs now... I missed them before because they did not have enough keywords in the summary.

*** This bug has been marked as a duplicate of bug 550027 ***

Comment 3 Matt McCutchen 2011-08-30 04:04:29 UTC
Actually my proposal is different from the previous bugs: repoquery --qf '%{NAME}\n' would remove the \n, leaving only repoquery's mandatory newline, but repoquery --qf '%{NAME}' would work as it does now.  Are you still not interested?  Are there actually programs passing \n that will break if they get one fewer blank line than before?

(In reply to bug 550027 comment #3)
> While the queryformat strings of rpm and repoquery are
> similar, there are numerous incompatibilities between them, you can't expect to
> copy-paste between rpm and repoquery query formats anyway.

Sure, the advanced features are incompatible, but it's a pity not to let simple things like --qf '%{NAME}\n' work the same way in both tools.

Comment 4 Panu Matilainen 2011-08-30 05:14:33 UTC
We can't possibly know what scripts users have built on top of repoquery, it's been out there long enough chances are somebody is relying on the current behavior with extra newline with trailing \n when explicitly added.

I suppose what we could do is add a --no-newline style switch which would then behave like rpm's queryformat.

Comment 5 seth vidal 2011-08-30 11:44:12 UTC
I don't think it is worth it and it just sets us up for having to provide other compatibilities with rpmq.

they are not the same syntax, they are similar - nothing else.

Comment 6 Matt McCutchen 2011-08-30 16:59:11 UTC
(In reply to comment #4)
> I suppose what we could do is add a --no-newline style switch which would then
> behave like rpm's queryformat.

That would not reduce the number of details a user has to remember to successfully port an rpmq command line to repoquery, so I wouldn't bother.  More generally, one could add an --rpmq switch that would activate all present and future tweaks for better rpmq compatibility and caution users that behavior differences between rpmq and "repoquery --rpmq" may go away at any time and should not be relied on.

(In reply to comment #5)
> and it just sets us up for having to provide other
> compatibilities with rpmq.

Not necessarily; if there are good arguments not to do that, you can make them at that time.

> they are not the same syntax, they are similar - nothing else.

So you added -q as an ignored option, but since then have backed away from the goal of compatibility with rpmq in simple cases?

It's disappointing to have an option with the same name and a limited but useful range of values that produce the same behavior in both programs, except for this newline issue.

Comment 7 James Antill 2011-08-30 20:02:26 UTC
 So, in theory, we could do this:

diff --git a/repoquery.py b/repoquery.py
index 0138251..24b899a 100755
--- a/repoquery.py
+++ b/repoquery.py
@@ -1226,6 +1226,9 @@ def main(args):
             print parser.format_help()
             sys.exit(1)
 
+    if opts.queryformat and opts.queryformat[-2:] == '\\n':
+        opts.queryformat = opts.queryformat[:-2]
+
     pkgops = []
     sackops = []
     archlist = None


...which would have the downside of breaking compatibility, but hopefully in a way not many people cared about ... and would be localized.
 I'm far from sure it's a good idea though.

Comment 8 Matt McCutchen 2011-08-30 20:11:33 UTC
Re comment #7: that's what my patch does, and we were discussing the implications in comment #3 and comment #4.

Comment 9 Fedora End Of Life 2012-08-07 20:04:36 UTC
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