fix: tweaks for building docs:

* check for NIPYPE_NO_MATLAB before doing code that may throw.
* Give better error messages when tools (dot) not installed.
* update gitignore for all built files.

Author: Ben Cipollini

.gitignore

@@ -5,6 +5,7 @@
 /nipype/build
 /nipype/nipype.egg-info
 /doc/_build
+/doc/preproc
 /doc/users/examples
 /doc/api/generated
 *.pyc

nipype/interfaces/base.py

@@ -1486,7 +1486,7 @@ def _run_interface(self, runtime, correct_return_codes=[0]):
         exist_val, cmd_path = _exists_in_path(executable_name,
                                               runtime.environ)
         if not exist_val:
-            raise IOError("%s could not be found on host %s" %
+            raise IOError("command '%s' could not be found on host %s" %
                           (self.cmd.split()[0], runtime.hostname))
         setattr(runtime, 'command_path', cmd_path)
         setattr(runtime, 'dependencies', get_dependencies(executable_name,

nipype/interfaces/spm/base.py

@@ -203,7 +203,7 @@ def no_spm():
     used with nosetests skipif to skip tests
     that will fail if spm is not installed"""
 
-    if Info.version() is None or 'NIPYPE_NO_MATLAB' in os.environ:
+    if 'NIPYPE_NO_MATLAB' in os.environ or Info.version() is None:
         return True
     else:
         return False

nipype/pipeline/utils.py

@@ -946,9 +946,17 @@ def export_graph(graph_in, base_dir=None, show=False, use_execgraph=False,
 
 
 def format_dot(dotfilename, format=None):
+    """Dump a directed graph (Linux only; install via `brew` on OSX)"""
     cmd = 'dot -T%s -O \'%s\'' % (format, dotfilename)
-    CommandLine(cmd).run()
-    logger.info('Converting dotfile: %s to %s format' % (dotfilename, format))
+    try:
+        CommandLine(cmd).run()
+    except IOError as ioe:
+        if "could not be found" in str(ioe):
+            raise IOError("Cannot draw directed graph; executable 'dot' is unavailable")
+        else:
+            raise ioe
+    else:
+        logger.info('Converting dotfile: %s to %s format' % (dotfilename, format))
 
 
 def make_output_dir(outdir):