Do not throw an exception when an invalid requisite is set

[mathieubouchard]

Description of Issue/Question

When an invalid require tag is set, there are no safety check in the code and an exception will be raised instead of showing a nice explanation of what is going on. It makes it really difficult to diagnose what's wrong with the SLS file.

Setup

Example SLS :

{% set pil = pillar['git'] %}

git:
  pkg.installed:
    - require:
      - file: {{ pil }}

The following exception will be raised :

    The minion function caused an exception: Traceback (most recent call last):
      File "/usr/lib/python2.6/site-packages/salt/minion.py", line 1320, in _thread_return
        return_data = executor.execute()
      File "/usr/lib/python2.6/site-packages/salt/executors/direct_call.py", line 28, in execute
        return self.func(*self.args, **self.kwargs)
      File "/usr/lib/python2.6/site-packages/salt/modules/state.py", line 722, in highstate
        whitelist=kwargs.get('whitelist')
      File "/usr/lib/python2.6/site-packages/salt/state.py", line 3271, in call_highstate
        os.umask(cumask)
      File "/usr/lib/python2.6/site-packages/salt/state.py", line 2276, in call_high
        return errors
      File "/usr/lib/python2.6/site-packages/salt/state.py", line 1799, in call_chunks
        running = self.call_chunk(low, running, chunks)
      File "/usr/lib/python2.6/site-packages/salt/state.py", line 2066, in call_chunk
        return running
      File "/usr/lib/python2.6/site-packages/salt/state.py", line 1982, in call_chunk
        requisites.append('prerequired')
      File "/usr/lib/python2.6/site-packages/salt/state.py", line 1868, in check_requisite
        if (fnmatch.fnmatch(chunk['name'], req_val) or
      File "/usr/lib64/python2.6/fnmatch.py", line 43, in fnmatch
        return fnmatchcase(name, pat)
      File "/usr/lib64/python2.6/fnmatch.py", line 75, in fnmatchcase
        res = translate(pat)
      File "/usr/lib64/python2.6/fnmatch.py", line 90, in translate
        c = pat[i]
    KeyError: 0

The line 1868 in /usr/lib/python2.6/site-packages/salt/state.py tries to compare two strings. In this case, a dictionary will be passed instead of a string. When the fnmatch method will try to match the values, it will access req_val[0], which is not a valid key for the dictionary.

Steps to Reproduce Issue

Write an invalid SLS with a require on a dictionary.

Versions Report

Salt Version:
Salt: 2016.3.2

Dependency Versions:
cffi: Not Installed
cherrypy: 3.2.2
dateutil: 1.4.1
gitdb: Not Installed
gitpython: Not Installed
ioflo: Not Installed
Jinja2: 2.2.1
libgit2: Not Installed
libnacl: Not Installed
M2Crypto: 0.20.2
Mako: Not Installed
msgpack-pure: Not Installed
msgpack-python: 0.4.6
mysql-python: Not Installed
pycparser: Not Installed
pycrypto: 2.6.1
pygit2: Not Installed
Python: 2.6.6 (r266:84292, May 22 2015, 08:34:51)
python-gnupg: Not Installed
PyYAML: 3.10
PyZMQ: 14.5.0
RAET: Not Installed
smmap: Not Installed
timelib: Not Installed
Tornado: 4.2.1
ZMQ: 4.0.5

System Versions:
dist: redhat 6.7 Santiago
machine: x86_64
release: 2.6.32-573.22.1.el6.x86_64
system: Linux
version: Red Hat Enterprise Linux Server 6.7 Santiago

[Ch3LL]

Agreed we should not be stacktracing here and put in a more useful error.

For future reference I was able to replicate this using the sls file above with the following pillar data:

git:
  test1: test

[cachedout]

Please see #35373