Q:

Debug Form.py files with Pydev and Qgis debug plugin

Following Python Qgis cookbook, qgis doc and other usefull docs, I succesfully installed and configure the debugger for pluggin as "hello world".
But, in the case of specific form, based on python script and Qt .ui files, I cannot figure out how to debug with the Pydev debug server.
I did :

run the debug server and the qgis plugin
set the python file path on Qgis
set the python file path on Pydev project, 
set a breakpoint on def formOpen(): function
open the form under Qgis

The debugger never stop on the breakpoint.

A:

For debug a QGIS plugins using your configuration and IDE the steps for eclipse projec are:

install eclipse
Install PyDev plugin for eclipse
Create a  in PyDev project your IDE 
Set the PyDev path in the  __init__.py (in my case)

try:
    sys.path.append("D:/eclipse/plugins/org.python.pydev_5.9.2.201708151115/pysrc")
except:
    pass

In your other class need import pydev:

try:
    import sys
    from pydevd import *
except:
    None

For put a break point you need put the first time settrace() for stop the code in this class

And for example in a Load-QSS Plugin I'm stopping the code when open a main form:

Note that I have put a settrace () before calling this method, this way if you will recognize the next breakpoint
You can show some functional QGIS plugins using this configuration in my Github account

