Bug 1270810 - diff sees non-existent differences
Summary: diff sees non-existent differences
Keywords:
Status: CLOSED EOL
Alias: None
Product: Fedora
Classification: Fedora
Component: diffutils
Version: 21
Hardware: x86_64
OS: Unspecified
unspecified
unspecified
Target Milestone: ---
Assignee: Tim Waugh
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2015-10-12 12:40 UTC by Andrew Dinn
Modified: 2015-12-02 18:20 UTC (History)
1 user (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2015-12-02 15:39:16 UTC
Type: Bug
Embargoed:


Attachments (Terms of Use)
first input file to diff command (365.34 KB, text/x-csrc)
2015-10-12 12:40 UTC, Andrew Dinn
no flags Details
second input file to diff (433.57 KB, text/x-csrc)
2015-10-12 12:41 UTC, Andrew Dinn
no flags Details

Description Andrew Dinn 2015-10-12 12:40:39 UTC
Created attachment 1081996 [details]
first input file to diff command

diff is seeing non-existent differences between two (mercurial) revisions of an input file. it correctly displays the actual differences introduced in the check-in. However, it also gets confused and displays differences between identical lines.


Version-Release number of selected component (if applicable):

  diff (GNU diffutils) 3.3

How reproducible:

Run diff on the two attached files aarch64.ad.0 and aarch64.ad.1

The output shows a sequence of changes for the block of 429 lines starting at aarch64.ad.0:4954 (ends at 5383) and aarch64.ad.1:6760 (ends at 7189)

Steps to Reproduce:
1. run diff on the two attached files aarch64.ad.0 and aarch64.ad.1
2.
3.

Actual results:
diff output for 428 lines starting at 4954/6760, respectively

Expected results:
no output for text in that region of the file

Additional info:

n.b. the two files include a very large change added to aarch64.ad.1 starting at line 1000. Removing this inserted text from aarch64.ad.1 stops the erroneous diff output from appearing.

When I tried chopping the inserted text down to the leading ~1/2 the erroneous diff was still present. Chopping to ~1/4 caused the the erroneous output to disappear. So, I thought hmm, lets try chopping just the leading ~1/4 but the erroneous output was still generated.

If I use hg diff to identify the differences between the two mercurial repo versions the erroneouosly signalled differences are not present. The mercurial version is

  Mercurial Distributed SCM (version 3.0)

Comment 1 Andrew Dinn 2015-10-12 12:41:13 UTC
Created attachment 1081997 [details]
second input file to diff

Comment 2 Fedora End Of Life 2015-11-04 10:12:40 UTC
This message is a reminder that Fedora 21 is nearing its end of life.
Approximately 4 (four) weeks from now Fedora will stop maintaining
and issuing updates for Fedora 21. It is Fedora's policy to close all
bug reports from releases that are no longer maintained. At that time
this bug will be closed as EOL if it remains open with a Fedora  'version'
of '21'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, simply change the 'version' 
to a later Fedora version.

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able to fix it before Fedora 21 is end of life. If you would still like 
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of Fedora, you are encouraged  change the 'version' to a later Fedora 
version prior this bug is closed as described in the policy above.

Although we aim to fix as many bugs as possible during every release's 
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Comment 3 Fedora End Of Life 2015-12-02 15:39:24 UTC
Fedora 21 changed to end-of-life (EOL) status on 2015-12-01. Fedora 21 is
no longer maintained, which means that it will not receive any further
security or bug fix updates. As a result we are closing this bug.

If you can reproduce this bug against a currently maintained version of
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