Support Jinja imports with relative paths. Issue #13889

Jinja imports will be interpreted as originating from the top of each
of the directories in the searchpath when the template name does not
begin with './' or '../'.  When a template name begins with './' or
'../' then the import will be relative to the importing file.

Prior practices required the following construct:

.. code-block:: yaml

  {% from tpldir ~ '/foo' import bar %}

This patch supports a more "natural" construct:

.. code-block:: yaml

  {% from './foo' import bar %}

Comparatively when importing from a parent directory - prior practice:

.. code-block:: yaml

  {% from tpldir ~ '/../foo' import bar %}

Construct supported by this patch:

.. code-block:: yaml

  {% from '../foo' import bar %}

salt/utils/jinja.py

@@ -98,20 +98,52 @@ class SaltCacheLoader(BaseLoader):
             self.cached.append(template)
 
     def get_source(self, environment, template):
-        # checks for relative '..' paths
-        if '..' in template:
-            log.warning(
-                'Discarded template path \'%s\', relative paths are '
-                'prohibited', template
-            )
-            raise TemplateNotFound(template)
+        '''
+        Salt-specific loader to find imported jinja files.
 
-        self.check_cache(template)
+        Jinja imports will be interpreted as originating from the top
+        of each of the directories in the searchpath when the template
+        name does not begin with './' or '../'.  When a template name
+        begins with './' or '../' then the import will be relative to
+        the importing file.
+        
+        '''
+        # FIXME: somewhere do seprataor replacement: '\\' => '/'
+        _template = template
+        if template.split('/', 1)[0] in ('..', '.'):
+            is_relative = True
+        else:
+            is_relative = False
+        # checks for relative '..' paths that step-out of file_roots
+        if is_relative:
+            # Starts with a relative path indicator
+
+            if not environment or 'tpldir' not in environment.globals:
+                log.warning(
+                    'Relative path "%s" cannot be resolved without an environment',
+                    template
+                )
+                print('Relative path "{0}" cannot be resolved without an environment'.format(template))
+                raise TemplateNotFound
+            base_path = environment.globals['tpldir']
+            _template = os.path.normpath('/'.join((base_path, _template)))
+            if _template.split('/', 1)[0] == '..':
+                log.warning(
+                    'Discarded template path "%s": attempts to'
+                    ' ascend outside of file roots', template
+                )
+                raise TemplateNotFound(template)
+
+        self.check_cache(_template)
 
         if environment and template:
-            tpldir = os.path.dirname(template).replace('\\', '/')
+            tpldir = os.path.dirname(_template).replace('\\', '/')
+            tplfile = _template
+            if is_relative:
+                tpldir = environment.globals.get('tpldir', tpldir)
+                tplfile = template
             tpldata = {
-                'tplfile': template,
+                'tplfile': tplfile,
                 'tpldir': '.' if tpldir == '' else tpldir,
                 'tpldot': tpldir.replace('/', '.'),
             }
@@ -119,7 +151,7 @@ class SaltCacheLoader(BaseLoader):
 
         # pylint: disable=cell-var-from-loop
         for spath in self.searchpath:
-            filepath = os.path.join(spath, template)
+            filepath = os.path.join(spath, _template)
             try:
                 with salt.utils.files.fopen(filepath, 'rb') as ifile:
                     contents = ifile.read().decode(self.encoding)
@@ -205,7 +237,7 @@ def skip_filter(data):
     '''
     Suppress data output
 
-    .. code-balock:: yaml
+    .. code-block:: yaml
 
         {% my_string = "foo" %}
 

tests/support/parser/__init__.py

@@ -332,7 +332,7 @@ class SaltTestingParser(optparse.OptionParser):
                         os.path.basename(fpath).startswith('test_'):
                     self.options.name.append(fpath)
                     continue
-                self.exit(status=1, msg='\'{}\' is not a valid test module'.format(fpath))
+                self.exit(status=1, msg='\'{}\' is not a valid test module\n'.format(fpath))
 
         print_header(u'', inline=True, width=self.options.output_columns)
         self.pre_execution_cleanup()

tests/unit/templates/files/rescape

@@ -0,0 +1 @@
+FAILURE

tests/unit/templates/files/test/relative/rescape

@@ -0,0 +1 @@
+{% import '../../rescape' as xfail -%}

tests/unit/templates/files/test/relative/rhello

@@ -0,0 +1,2 @@
+{% from './rmacro' import rmacro with context -%}
+{{ rmacro('Hey') ~ rmacro(a|default('a'), b|default('b')) }}

tests/unit/templates/files/test/relative/rmacro

@@ -0,0 +1,4 @@
+{% from '../macro' import mymacro with context %}
+{% macro rmacro(greeting, greetee='world') -%}
+{{ mymacro(greeting, greetee) }}
+{%- endmacro %}

tests/unit/templates/test_jinja.py

@@ -170,6 +170,23 @@ class TestSaltCacheLoader(TestCase):
         self.assertEqual(fc.requests[0]['path'], 'salt://hello_import')
         self.assertEqual(fc.requests[1]['path'], 'salt://macro')
 
+    def test_relative_import(self):
+        '''
+        You can import using relative paths
+        issue-13889
+        '''
+        fc, jinja = self.get_test_saltenv()
+        tmpl = jinja.get_template('relative/rhello')
+        result = tmpl.render()
+        self.assertEqual(result, 'Hey world !a b !')
+        assert len(fc.requests) == 3
+        self.assertEqual(fc.requests[0]['path'], 'salt://relative/rhello')
+        self.assertEqual(fc.requests[1]['path'], 'salt://relative/rmacro')
+        self.assertEqual(fc.requests[2]['path'], 'salt://macro')
+        # This must fail when rendered: attempts to import from outside file root
+        template = jinja.get_template('relative/rescape')
+        self.assertRaises(exceptions.TemplateNotFound, template.render)
+
     def test_include(self):
         '''
         You can also include a template that imports and uses macros