gitweb: escape html in rss title

The title of an RSS feed is generated from many components,
including the filename provided as a query parameter, but we
failed to quote it.  Besides showing the wrong output, this
is a vector for XSS attacks.

Signed-off-by: Jeff King <peff@peff.net>
checkout: print a message when switching unborn branches

When we switch to a new branch using checkout, we usually output a
message indicating what happened. However, when we switch from an unborn
branch to a new branch, we do not print anything, which may leave the
user wondering what happened.

The reason is that the unborn branch is a special case (see abe1998),
and does not follow the usual switch_branches code path. Let's add a
similar informational message to the special case to match the usual
code path.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
config: don't segfault when given --path with a missing value

When given a variable without a value, such as '[section] var' and
asking git-config to treat it as a path, git_config_pathname returns
an error and doesn't modify its output parameter. show_config assumes
that the call is always successful and sets a variable to indicate
that vptr should be freed. In case of an error however, trying to do
this will cause the program to be killed, as it's pointing to memory
in the stack.

Detect the error and return immediately to avoid freeing or accessing
the uninitialed memory in the stack.

Signed-off-by: Carlos Martín Nieto <cmn@elego.de>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Completion must sort before using uniq

The user can be presented with invalid completion results
when trying to complete a 'git checkout' command.  This can happen
when using a branch name prefix that matches multiple remote branches.

For example, if available branches are:
  master
  remotes/GitHub/maint
  remotes/GitHub/master
  remotes/origin/maint
  remotes/origin/master

When performing completion on 'git checkout ma' the user will be
given the choices:
  maint
  master

However, 'git checkout maint' will fail in this case, although
completion previously said 'maint' was valid.  Furthermore, when
performing completion on 'git checkout mai', no choices will be
suggested.  So, the user is first told that the branch name
'maint' is valid, but when trying to complete 'mai' into 'maint',
that completion is no longer valid.

The completion results should never propose 'maint' as a valid
branch name, since 'git checkout' will refuse it.

The reason for this bug is that the uniq program only
works with sorted input.  The man page states
"uniq prints the unique lines in a sorted file".

When __git_refs uses the guess heuristic employed by checkout for
tracking branches it wants to consider remote branches but only if
the branch name is unique.  To do that, it calls 'uniq -u'.  However
the input given to 'uniq -u' is not sorted.

Therefore, in the above example, when dealing with 'git checkout ma',
"__git_refs '' 1" will find the following list:
  master
  maint
  master
  maint
  master

which, when passed to 'uniq -u' will remain the same.  Therefore
'maint' will be wrongly suggested as a valid option.

When dealing with 'git checkout mai', the list will be:
  maint
  maint

which happens to be sorted and will be emptied by 'uniq -u',
properly ignoring 'maint'.

A solution for preventing the completion script from suggesting
such invalid branch names is to first call 'sort' and then 'uniq -u'.

Signed-off-by: Marc Khouzam <marc.khouzam@gmail.com>
Reviewed-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'jk/maint-gitweb-xss' into maint

Fixes an XSS vulnerability in gitweb.

* jk/maint-gitweb-xss:
  gitweb: escape html in rss title
Merge branch 'cn/config-missing-path' into maint

* cn/config-missing-path:
  config: don't segfault when given --path with a missing value
Merge branch 'jk/checkout-out-of-unborn' into maint

* jk/checkout-out-of-unborn:
  checkout: print a message when switching unborn branches
Git 1.8.0.1

Signed-off-by: Junio C Hamano <gitster@pobox.com>