xz 5.0.3 (i386/NetBSD 5.0) strange "Unexpected end of input"

[Robert Elz <kre%munnari.OZ.AU@localhost>]

I'm running pkg_info (from pkgtools 20120128 if it matters) which
seems to use xz 5.0.3 when examining a binary package file that
was built with xz compression (such as many of the recent ones on
ftp.netbsd.org).  xz 5.0.3 looks to be the current version.

I noticed that I was seeing
        unxz: (stdin): Unexpected end of input
occasionally - I was running pkg_info from a context where it was
examining a whole directory of binpkg files, and this gave no idea
which file was (apparently) corrupt.

So, I tried just

        for f in *; do echo $f; pkg_info -nq $f >/dev/null; done

so I could see which file(s) were bad, initially with the intent
of replacing them (for this, I obviously wasn't interested in any
output from pkg_info, just to find which files it complained about).

Problem was, the output from this loop wasn't consistent.  So I ran
it 3 times...

for f in *; do echo $f; pkg_info -nq $f >/dev/null; done >/tmp/L1 2>&1
for f in *; do echo $f; pkg_info -nq $f >/dev/null; done >/tmp/L2 2>&1
for f in *; do echo $f; pkg_info -nq $f >/dev/null; done >/tmp/L3 2>&1

Then...

        for f in 1 2 3
        do
                grep unxz /tmp/L$f | wc -l
        done
             121
             178
              95

which is weird...   What's more, there looks to be no commonality at
all in which files are reported as having the error.  (There is
nothing matching *unxz* in the directory, so the grep is just finding,
and wc counting, the errors produced, not any of the "echo $f" output.)

Those numbers look large, but "*" expands to 11000+ packages, so
at most, the error occurs < 2% of the time.

I have appended the (initial parts of) "diff -u1" of the three pairings of
L1 L2 and L3.

Anyone have any idea what might be happening here?

kre

ps: for what it is worth, as best I can tell anyway, the pkg_info
commands I was running worked OK, they just produced this obscure
diagnostic sometimes.  However, I am assuming the "OK" based
upon lack of other perceived problems.

--- /tmp/L1     2012-06-26 19:19:22.000000000 +0700
+++ /tmp/L2     2012-06-26 19:24:58.000000000 +0700
@@ -13,2 +13,3 @@
 9term-1.6.3nb1.tgz
+unxz: (stdin): Unexpected end of input
 9wm-1.1nb2.tgz
@@ -19,2 +20,3 @@
 BibTool-2.48.tgz
+unxz: (stdin): Unexpected end of input
 BitTornado-0.3.18nb5.tgz
@@ -23,2 +25,3 @@
 CSP-0.32nb5.tgz
+unxz: (stdin): Unexpected end of input
 CUnit-2.1.tgz
@@ -108,2 +111,3 @@
 R-classInt-0.1.14.tgz
+unxz: (stdin): Unexpected end of input
 R-clim.pact-2.2.39.tgz
@@ -133,3 +137,2 @@
 R-wle-0.9.3nb1.tgz
-unxz: (stdin): Unexpected end of input
 RBTools-0.2nb1.tgz
@@ -236,3 +239,2 @@
 akode-plugins-mpc-2.0.2nb1.tgz
-unxz: (stdin): Unexpected end of input
 akode-plugins-mpeg-2.0.2nb1.tgz
@@ -341,3 +343,2 @@
 ap2-cband-0.9.7.5.tgz
-unxz: (stdin): Unexpected end of input
 ap2-chroot-0.5.tgz
@@ -415,3 +416,2 @@
 apache-maven-2.2.1.tgz
-unxz: (stdin): Unexpected end of input
 apache-roller-4.0.1nb2.tgz
@@ -444,3 +444,2 @@
 ario-1.5.1nb4.tgz
-unxz: (stdin): Unexpected end of input
 arirang-1.6nb1.tgz
@@ -500,3 +499,2 @@
 asterisk-sounds-extra-1.2.1.tgz
-unxz: (stdin): Unexpected end of input
 asterisk-sounds-native-20060209.tgz
@@ -593,3 +591,2 @@
 bbkeys-0.8.6nb1.tgz
-unxz: (stdin): Unexpected end of input
 bbmail-0.8.3nb1.tgz
@@ -601,3 +598,2 @@
 bcc-95.3.12nb1.tgz
-unxz: (stdin): Unexpected end of input
 bchunk-1.2.0.tgz
@@ -644,3 +640,2 @@
 bitchx-1.1nb4.tgz
-unxz: (stdin): Unexpected end of input
 bitlbee-3.0.3nb4.tgz
@@ -729,3 +724,2 @@
 bsdtar-2.8.4.tgz
-unxz: (stdin): Unexpected end of input
 bsetroot-0.1nb7.tgz
@@ -770,3 +764,2 @@
 cacti-0.8.7inb2.tgz
-unxz: (stdin): Unexpected end of input
 cadaver-0.23.3nb1.tgz

--- /tmp/L1     2012-06-26 19:19:22.000000000 +0700
+++ /tmp/L3     2012-06-26 19:31:49.000000000 +0700
@@ -13,2 +13,3 @@
 9term-1.6.3nb1.tgz
+unxz: (stdin): Unexpected end of input
 9wm-1.1nb2.tgz
@@ -30,2 +31,3 @@
 Cenon-3.83nb3.tgz
+unxz: (stdin): Unexpected end of input
 Cg-compiler-1.3beta2nb3.tgz
@@ -111,3 +113,2 @@
 R-date-1.2.29.tgz
-unxz: (stdin): Unexpected end of input
 R-e1071-1.5.24.tgz
@@ -123,2 +124,3 @@
 R-maps-2.1.0.tgz
+unxz: (stdin): Unexpected end of input
 R-mvtnorm-0.9.8.tgz
@@ -133,3 +135,2 @@
 R-wle-0.9.3nb1.tgz
-unxz: (stdin): Unexpected end of input
 RBTools-0.2nb1.tgz
@@ -236,3 +237,2 @@
 akode-plugins-mpc-2.0.2nb1.tgz
-unxz: (stdin): Unexpected end of input
 akode-plugins-mpeg-2.0.2nb1.tgz
@@ -279,2 +279,3 @@
 amule-2.2.6nb8.tgz
+unxz: (stdin): Unexpected end of input
 an-0.93.tgz
@@ -341,6 +342,4 @@
 ap2-cband-0.9.7.5.tgz
-unxz: (stdin): Unexpected end of input
 ap2-chroot-0.5.tgz
 ap2-fastcgi-2.4.6.tgz
-unxz: (stdin): Unexpected end of input
 ap2-fcgid-2.3.6.tgz
@@ -415,3 +414,2 @@
 apache-maven-2.2.1.tgz
-unxz: (stdin): Unexpected end of input
 apache-roller-4.0.1nb2.tgz
@@ -444,3 +442,2 @@
 ario-1.5.1nb4.tgz
-unxz: (stdin): Unexpected end of input
 arirang-1.6nb1.tgz
@@ -500,3 +497,2 @@
 asterisk-sounds-extra-1.2.1.tgz
-unxz: (stdin): Unexpected end of input
 asterisk-sounds-native-20060209.tgz
@@ -569,2 +565,3 @@
 baekmuk-ttf-2.2nb2.tgz
+unxz: (stdin): Unexpected end of input
 bakoma-fonts-1.1.tgz
@@ -574,2 +571,3 @@
 barcode-0.98.tgz
+unxz: (stdin): Unexpected end of input
 barnyard-0.2.0nb1.tgz
@@ -593,3 +591,2 @@
 bbkeys-0.8.6nb1.tgz
-unxz: (stdin): Unexpected end of input
 bbmail-0.8.3nb1.tgz

--- /tmp/L2     2012-06-26 19:24:58.000000000 +0700
+++ /tmp/L3     2012-06-26 19:31:49.000000000 +0700
@@ -20,3 +20,2 @@
 BibTool-2.48.tgz
-unxz: (stdin): Unexpected end of input
 BitTornado-0.3.18nb5.tgz
@@ -25,3 +24,2 @@
 CSP-0.32nb5.tgz
-unxz: (stdin): Unexpected end of input
 CUnit-2.1.tgz
@@ -33,2 +31,3 @@
 Cenon-3.83nb3.tgz
+unxz: (stdin): Unexpected end of input
 Cg-compiler-1.3beta2nb3.tgz
@@ -111,3 +110,2 @@
 R-classInt-0.1.14.tgz
-unxz: (stdin): Unexpected end of input
 R-clim.pact-2.2.39.tgz
@@ -115,3 +113,2 @@
 R-date-1.2.29.tgz
-unxz: (stdin): Unexpected end of input
 R-e1071-1.5.24.tgz
@@ -127,2 +124,3 @@
 R-maps-2.1.0.tgz
+unxz: (stdin): Unexpected end of input
 R-mvtnorm-0.9.8.tgz
@@ -281,2 +279,3 @@
 amule-2.2.6nb8.tgz
+unxz: (stdin): Unexpected end of input
 an-0.93.tgz
@@ -345,3 +344,2 @@
 ap2-fastcgi-2.4.6.tgz
-unxz: (stdin): Unexpected end of input
 ap2-fcgid-2.3.6.tgz
@@ -567,2 +565,3 @@
 baekmuk-ttf-2.2nb2.tgz
+unxz: (stdin): Unexpected end of input
 bakoma-fonts-1.1.tgz
@@ -572,2 +571,3 @@
 barcode-0.98.tgz
+unxz: (stdin): Unexpected end of input
 barnyard-0.2.0nb1.tgz
@@ -695,2 +695,3 @@
 boost-docs-1.49.0.tgz
+unxz: (stdin): Unexpected end of input
 boost-headers-1.49.0.tgz
@@ -869,3 +870,2 @@
 civctp-demo-19991025nb1.tgz
-unxz: (stdin): Unexpected end of input
 cjkutils-4.8.2.tgz
@@ -877,2 +877,3 @@
 claraocr-0.9.9nb1.tgz
+unxz: (stdin): Unexpected end of input
 classpath-0.93nb4.tgz
@@ -941,2 +942,3 @@
 cmake-2.8.7.tgz
+unxz: (stdin): Unexpected end of input
 cmake-fedora-0.8.1.tgz
@@ -1224,3 +1226,2 @@
 dict-data-1.8.0nb1.tgz
-unxz: (stdin): Unexpected end of input
 dict-mueller7-1.2.tgz