Bug 97092

Summary:	Object generation numbers aren't updated (except in the xref table)
Product:	poppler	Reporter:	Jakub Alba <jakubalba>
Component:	general	Assignee:	poppler-bugs <poppler-bugs>
Status:	RESOLVED MOVED	QA Contact:
Severity:	normal
Priority:	medium	CC:	jakubalba
Version:	unspecified
Hardware:	Other
OS:	All
Whiteboard:
i915 platform:		i915 features:
Attachments:	[PATCH] fix xref entry ref.gen updating

Description Jakub Alba 2016-07-27 06:31:29 UTC

If you update an object, its generation number will only be incremented in the cross-reference table, but e.g. not in the object header or, if it is the "Info" dictionary, in the "Info" entry of the trailer dictionary.

To reproduce this bug, update an object (e.g. modify a single annotation in evince) and use "tail" unix utility with the "-n" option big enough (e.g. 100) to see the object header of the updated object. No matter how many times you update the object, the generation number is still the same. The generation number in the cross-reference table will be updated though.

Comment 1 Jakub Alba 2016-07-27 06:32:04 UTC

Created attachment 125347 [details] [review]
[PATCH] fix xref entry ref.gen updating

Comment 2 Jakub Alba 2016-07-27 14:27:41 UTC

After some testing it seems that although it fixed the case of modifying annotations, it break the case of adding them. I will send a fix here if I figure out why this happens. Right now - no idea.

Comment 3 Jakub Alba 2016-07-27 15:33:48 UTC

Ok. It doesn't happen if you use a non-poppler PDF viewer. It's largely a fault of the code responsible for reading a PDF. But it seems to me that at this point it's just too complex to fix. Perhaps it doesn't work as it ideally should, but well, it still works, so maybe let's leave it like that.

Comment 4 GitLab Migration User 2018-08-21 11:15:03 UTC

-- GitLab Migration Automatic Message --

This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.

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