Add check for float32 and float64 to check_type

[mintar]

Fixes #130.

Specifically, this PR improves the error messages during serialization. Consider the following script:

from io import BytesIO
from geometry_msgs.msg import PoseStamped

msg = PoseStamped()
msg.pose.position.x = '0.0'
buff = BytesIO()
msg.serialize(buff)

Old behavior:

Traceback (most recent call last):
  File "/opt/ros/noetic/lib/python3/dist-packages/geometry_msgs/msg/_PoseStamped.py", line 106, in serialize
    buff.write(_get_struct_7d().pack(_x.pose.position.x, _x.pose.position.y, _x.pose.position.z, _x.pose.orientation.x, _x.pose.orientation.y, _x.pose.orientation.z, _x.pose.orientation.w))
struct.error: required argument is not a float

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "src/genpy/test.py", line 9, in <module>
    msg.serialize(buff)
  File "/opt/ros/noetic/lib/python3/dist-packages/geometry_msgs/msg/_PoseStamped.py", line 107, in serialize
    except struct.error as se: self._check_types(struct.error("%s: '%s' when writing '%s'" % (type(se), str(se), str(locals().get('_x', self)))))
  File "/opt/ros/noetic/lib/python3/dist-packages/genpy/message.py", line 364, in _check_types
    raise SerializationError(str(exc))
genpy.message.SerializationError: <class 'struct.error'>: 'required argument is not a float' when writing 'header: 
  seq: 0
  stamp: 
    secs: 0
    nsecs:         0
  frame_id: ''
pose: 
  position: 
    x: "0.0"
    y: 0.0
    z: 0.0
  orientation: 
    x: 0.0
    y: 0.0
    z: 0.0
    w: 0.0'

New behavior:

Traceback (most recent call last):
  File "/opt/ros/noetic/lib/python3/dist-packages/geometry_msgs/msg/_PoseStamped.py", line 106, in serialize
    buff.write(_get_struct_7d().pack(_x.pose.position.x, _x.pose.position.y, _x.pose.position.z, _x.pose.orientation.x, _x.pose.orientation.y, _x.pose.orientation.z, _x.pose.orientation.w))
struct.error: required argument is not a float

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "src/genpy/test.py", line 9, in <module>
    msg.serialize(buff)
  File "/opt/ros/noetic/lib/python3/dist-packages/geometry_msgs/msg/_PoseStamped.py", line 107, in serialize
    except struct.error as se: self._check_types(struct.error("%s: '%s' when writing '%s'" % (type(se), str(se), str(locals().get('_x', self)))))
  File "/ws/src/genpy/src/genpy/message.py", line 392, in _check_types
    check_type(n, t, getattr(self, n))
  File "/ws/src/genpy/src/genpy/message.py", line 323, in check_type
    check_type('%s.%s' % (field_name, n), t, getattr(field_val, n))
  File "/ws/src/genpy/src/genpy/message.py", line 323, in check_type
    check_type('%s.%s' % (field_name, n), t, getattr(field_val, n))
  File "/ws/src/genpy/src/genpy/message.py", line 272, in check_type
    raise SerializationError('field %s must be float type' % field_name)
genpy.message.SerializationError: field pose.position.x must be float type

[mintar]

@dirk-thomas : If you don't like the added numpy dependency, we could avoid it like this (at the cost of doing not-so-nice string comparisons instead of type comparisons):

click to see outdated code

diff --git i/package.xml w/package.xml
index 0f09e82..5af3210 100644
--- i/package.xml
+++ w/package.xml
@@ -24,8 +24,8 @@
   <buildtool_depend condition="$ROS_PYTHON_VERSION == 2">python-setuptools</buildtool_depend>
   <buildtool_depend condition="$ROS_PYTHON_VERSION == 3">python3-setuptools</buildtool_depend>
 
-  <exec_depend condition="$ROS_PYTHON_VERSION == 2">python-numpy</exec_depend>
-  <exec_depend condition="$ROS_PYTHON_VERSION == 3">python3-numpy</exec_depend>
+  <test_depend condition="$ROS_PYTHON_VERSION == 2">python-numpy</test_depend>
+  <test_depend condition="$ROS_PYTHON_VERSION == 3">python3-numpy</test_depend>
 
   <exec_depend condition="$ROS_PYTHON_VERSION == 2">python-yaml</exec_depend>
   <exec_depend condition="$ROS_PYTHON_VERSION == 3">python3-yaml</exec_depend>
diff --git i/src/genpy/message.py w/src/genpy/message.py
index ad9f229..8e57c3b 100644
--- i/src/genpy/message.py
+++ w/src/genpy/message.py
@@ -43,8 +43,6 @@ import math
 import struct
 import sys
 
-import numpy as np
-
 import genmsg
 
 import yaml
@@ -264,7 +262,8 @@ def check_type(field_name, field_type, field_val):
             if field_val >= maxval:
                 raise SerializationError('field %s exceeds specified width [%s]' % (field_name, field_type))
         elif field_type in ['float32', 'float64']:
-            if type(field_val) not in [float, int, long, np.float32, np.float64, np.int8, np.int16, np.int32, np.int64, np.uint8, np.uint16, np.uint32, np.uint64]:
+            if type(field_val) not in [float, int, long] and not (type(field_val).__module__ == 'numpy' and type(field_val).__name__ in
+                    ['float32', 'float64', 'int8', 'int16', 'int32', 'int64', 'uint8', 'uint16', 'uint32', 'uint64']):
                 raise SerializationError('field %s must be float type' % field_name)
         elif field_type == 'bool':
             if field_val not in [True, False, 0, 1]:

Edit: Never mind, I've just pushed a commit (0f37e30) that avoids the numpy dependency this in a better way.

[dirk-thomas]

Thanks for the improvement.