bin/60663: Inconsistent diff output!

[Doug Lee]

>Number:         60663
>Category:       bin
>Synopsis:       Inconsistent diff output!
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun Dec 28 11:40:08 PST 2003
>Closed-Date:
>Last-Modified:
>Originator:     Doug Lee
>Release:        FreeBSD 4.9-RC i386
>Organization:
>Environment:
System: FreeBSD kirk.dlee.org 4.9-RC FreeBSD 4.9-RC #0: Sat Oct 4 05:16:52 EDT 2003 dgl at kirk.dlee.org:/usr2/obj/usr/src/sys/CUSTOM i386


	
>Description:
I have two subdirectories (CVSROOT copies, actually) for which I get
inconsistent results as follows:

If I diff the "modules" files alone, I get correct output; but if I
diff the whole directories (with or without -r), the output for
"modules" is wrong:  It leaves out one line and acts as if it misses
one line of one of the input files.  NOTE:  This is /usr/bin/diff, NOT
"cvs diff."  I haven't tried CVS's built-in diff here.
>How-To-Repeat:
Given directories cv1 and cv2 (I'll provide a tar file to whichever
tester requests it), the first of the following commands produces
correct output, while the second omits a line as shown:

% diff cv1/modules cv2/modules
28,33c28,29
< # These modules are Bart projects now being managed by CVS.
< bx bart/bx
< delta bart/delta
< dt -a delta
< lib bart/lib
< qex bart/qex
---
> dbin -d bin dgl/develop/bin
> cc shepherd/chatclient

% diff cv1 cv2
diff cv1/.#cvsignore cv2/.#cvsignore
2d1
< ex.rc EX.RC
diff cv1/.#cvswrappers cv2/.#cvswrappers
19a20
> 
24,31c25,28
< *.mpg -k 'b'
< *.MPG -k 'b'
< *.jpeg -k 'b'
< *.JPEG -k 'b'
< *.mpeg -k 'b'
< *.MPEG -k 'b'
< *.jsb -k 'b'
< *.JSB -k 'b'
---
> *.mp3 -k 'b'
> *.MP3 -k 'b'
> *.wav -k 'b'
> *.WAV -k 'b'
diff cv1/.#modules cv2/.#modules
28,32c28
[*** WRONG ***  should be 28,33c28,29]
< # These modules are Bart projects now being managed by CVS.
< bx bart/bx
< delta bart/delta
< dt -a delta
< qex bart/qex
[*** WRONG ***  skipped the "lib bart/lib" line]
---
> dbin -d bin dgl/develop/bin
[*** WRONG ***  there should be one more line]
Common subdirectories: cv1/Emptydir and cv2/Emptydir
[...further lines of output omitted]

>Fix:

	


>Release-Note:
>Audit-Trail:
>Unformatted: