Bug#836820: gdb: Python Exception expected string or bytes-like object:

[Mike Hommey]

Package: gdb
Version: 7.11.1-2
Severity: normal

While fiddling with jemalloc structures in Firefox under gdb, I hit the
error message in the bug subject. The full steps to reproduce:

$ mkdir /tmp/foo
$ gdb --args firefox.real -profile /tmp/foo -new-instance
(gdb) start
(gdb) print huge->rbt_root
Python Exception <class 'TypeError'> expected string or bytes-like object: 
Error while looking for matching xmethod workers defined in Python.

I haven't added any python xmethods. Here are the ones I have:

(gdb) info xmethod
Xmethods in objfile /usr/lib/x86_64-linux-gnu/libstdc++.so.6:
  libstdc++::unique_ptr
    operator->
    get
    operator*
  libstdc++::unordered_multimap
    empty
    size
  libstdc++::unordered_multiset
    empty
    size
  libstdc++::unordered_map
    empty
    size
  libstdc++::unordered_set
    empty
    size
  libstdc++::multimap
    empty
    size
  libstdc++::multiset
    empty
    size
  libstdc++::map
    empty
    size
  libstdc++::set
    empty
    size
  libstdc++::vector
    size
    at
    operator[]
    empty
    back
    front
  libstdc++::list
    empty
    front
    back
    size
  libstdc++::deque
    size
    at
    operator[]
    empty
    back
    front
  libstdc++::forward_list
    empty
    front
  libstdc++::array
    size
    at
    operator[]
    empty
    back
    front

Disabling them makes it work:
(gdb) disable xmethod
(gdb) print huge->rbt_root
$1 = (extent_node_t *) 0x555555772568 <huge+8>


-- System Information:
Debian Release: stretch/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.7.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=ja_JP.UTF-8, LC_CTYPE=ja_JP.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages gdb depends on:
ii  libbabeltrace-ctf1  1.4.0-3
ii  libbabeltrace1      1.4.0-3
ii  libc6               2.24-2
ii  libexpat1           2.2.0-1
ii  liblzma5            5.1.1alpha+20120614-2.1
ii  libncurses5         6.0+20160625-1
ii  libpython3.5        3.5.2-4
ii  libreadline6        6.3-8+b4
ii  libtinfo5           6.0+20160625-1
ii  zlib1g              1:1.2.8.dfsg-2+b1

Versions of packages gdb recommends:
ii  gdbserver             7.11.1-2
ii  libc6-dbg [libc-dbg]  2.24-2

Versions of packages gdb suggests:
pn  gdb-doc  <none>

-- no debconf information