[Pkg-fonts-devel] Bug#483791: FreeSans: Pango-WARNING **: Error loading GPOS table 5503

[Peter Moulder]

Package: ttf-freefont
Version: 20080323-3
Severity: normal

I noticed that gucharmap was giving an "Error loading GPOS table"
message on stderr, so I googled for that error, and apparently it's when
pango believes that a font has an error.  Note that in one case in the
past, it turned out that pango needed to be modified to change its test.
You may wish to discuss this error with the harfbuzz developers.

Here's an "end-user-visible" way of reproducing:

  Start gedit from a terminal (so you can see its stderr).
  Edit>Preferences>Font & Colors
  Click the Editor Font button
  Click in the Family list
  Use down arrow until you get to FreeSans
  Note that nothing is produced on stderr until you get to the FreeSans
   item, at which point the following is produced on stderr:

      (gedit:27436): Pango-WARNING **: Error loading GPOS table 5503

  (You could then try exiting gedit, starting it again, and this time
  selecting the font family after FreeSans in the list, and use
  down-arrow key to iterate over all remaining fonts, and note that no
  other font family produces an error.  At least, no other font family
  installed on my system produces an error.)


A more useful way of reproducing is with the test program included in
pango:

  apt-get install libpango1.0-dev
  apt-get source pango1.0
  # I usually use apt-get source -d with separate dpkg-source -x -sn
  # step so that I can extract it as a non-root user.
  cd pango1.0-1.20.2/pango/opentype
  gcc -g -Wall `pkg-config --cflags pangoft2` -o harfbuzz-dump \
   harfbuzz-dump-main.c harfbuzz-dump.c harfbuzz-gpos.c harfbuzz-gsub.c \
   harfbuzz-buffer.c harfbuzz-gdef.c harfbuzz-open.c harfbuzz-stream.c \
   harfbuzz-impl.c `pkg-config --libs pangoft2`
  # `make harfbuzz-dump' after configuring with `--disable-shared' and
  # `CFLAGS=-g' would probably work too.

  # At this point one might like to check whether FreeSans.ttf is the only
  # font on the system that gives an error:
  for i in $(find /usr/share/fonts/truetype -type f); do 
    ./harfbuzz-dump "$i" 2>&1 | grep -i 'error' && printf '%s\n\n' "$i" ;done

  # Or just go straight to FreeSans.ttf:
  ./harfbuzz-dump /usr/share/fonts/truetype/freefont/FreeSans.ttf >/dev/null

After some search from within gdb, I get to the following point where
the error in question is produced:

  Load_Anchor (an=0x807b540, stream=0x8070398) at harfbuzz-gpos.c:566
  (gdb) n
  (gdb) 
  (gdb) 
  (gdb) p an->PosFormat
  $27 = 56
  (gdb) bt
  #0  Load_Anchor (an=0x807b540, stream=0x8070398) at harfbuzz-gpos.c:573
  #1  0x08051724 in Load_Mark2Array (m2a=0x80757a0, num_classes=2, 
      stream=0x8070398) at harfbuzz-gpos.c:2803
  #2  0x08051c94 in Load_MarkMarkPos (st=0x8075778, stream=0x8070398)
      at harfbuzz-gpos.c:2927
  #3  0x08058559 in _HB_GPOS_Load_SubTable (st=0x8075778, stream=0x8070398, 
      lookup_type=6) at harfbuzz-gpos.c:5878
  #4  0x08066112 in Load_SubTable (st=0x8075778, stream=0x8070398, 
      table_type=HB_Type_GPOS, lookup_type=6) at harfbuzz-open.c:458
  #5  0x080664de in Load_Lookup (l=0x807b3b0, stream=0x8070398, 
      type=HB_Type_GPOS) at harfbuzz-open.c:536
  #6  0x080667d9 in _HB_OPEN_Load_LookupList (ll=0x8074ba4, stream=0x8070398, 
      type=HB_Type_GPOS) at harfbuzz-open.c:618
  #7  0x0804bb98 in HB_Load_GPOS_Table (font=0x80703c8, retptr=0xbf8ef070, 
      gdef=0x0) at harfbuzz-gpos.c:141
  #8  0x08048a1a in main (argc=2, argv=0xbf8ef124) at harfbuzz-dump-main.c:211
  (gdb) 

(To get to this point, do b Load_Mark2Array, and do `n' (next) until the
second iteration of the `for n' loop, i.e. where n = 1.)

pjrm.


-- System Information:
Debian Release: lenny/sid
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'stable')
Architecture: i386 (i686)

Kernel: Linux 2.6.24-1-686 (SMP w/2 CPU cores)
Locale: LANG=C, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages ttf-freefont depends on:
ii  defoma                       0.11.10-0.2 Debian Font Manager -- automatic f

Versions of packages ttf-freefont recommends:
ii  x-ttcidfont-conf              27         TrueType and CID fonts configurati

-- no debconf information