Python syntax error not showing in output window

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1

Hi,

I just updated from Revit 2026 to 2027 and from pyrevit 5.2.0 to 6.5.3.
When checking if my scripts needed any modifications to work with the new revit version I found that when there is a syntax error in my code it doesn’t get printed to the output window anymore.
The output window does show up but stays white.

I double checked with a different computer that has revit 2026 and pyrevit 5.2.0 with the same kind of syntax error and there it does get printed.

Perhaps something I need to change in the settings?

All of my scripts have the same layout where there is an A_main_script.py that handles the interface in B_interface.py and logic that is placed in C_some_name.py .

import os
import sys

current_dir = os.path.dirname(os.path.abspath(__file__))
sys.path.append(os.path.abspath(os.path.join(current_dir, "..")))
sys.path.append(os.path.abspath(os.path.join(current_dir, "..", "..")))


from MK import check_project_information
check_project_information.main()


from pyrevit import revit, output

import B_interface as interface
import C_Grid


def main():
    #Show the interface
    window = interface.GridWindow()

    # If data has been filled in and the ok button has been pressed proceed
    if window.should_run_script:
        with revit.Transaction("Create grids") as t:
            C_Grid.GridMaker(window).main()


if __name__ == "__main__":
    main()

    out_window = output.get_output()
    out_window.close()
2

How do you know there is a syntax error if it does not get printed?

3

Visual studio code indicates one of the functions can’t be found.
Upon further investigation it seems that errors in the A_main_script.py do print to the output window but errors in imported modules sometimes do and sometimes don’t show up.

C_Grid.GridMaker(window).main()

calls:

    def main(self):
        self.insert_input_in_project_information()
        self.remove_all_grids()
        self.create_new_grids()

Running it works but changing the last line so it’s incorrect gives varying results.
self.create_new_grids1() results in the correct error printed:

INFO: Deleted 47 old grid lines

ERROR [pyrevit.revit.db.transaction] Error in Transaction Context. Rolling back changes. | <type 'exceptions.AttributeError'>:GridMaker instance has no attribute 'create_new_grids1'

self.create_new_grids2() results in no error printed but program is stopped.

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Any further changes to the line also result in no error getting printed.
When I remove the extra number at the end so it’s back to the original line the code immediatly just runs fine.

I’m quite certain I had the same in my A_main_script.py but I am unable to reproduce the missing prints when modifying this file.

4

After further research I seem to have found a solution.
Adding:
__cleanengine__ = True
to the start of my A_main_script.py seems to resolve the issue.

5

I’m in a very similar situation as the one posted. Upgrading from 5.2.0 to 6.5.3 for 2027 support, errors are not printing traceback to output window (output window pops up, so I know there’s an error, but no content gets printed).
Same behavior seen, where errors in imported modules print correctly, and Syntax errors (python parsing errors, EG: unclosed bracket) print correctly, but other errors do not (EG: Object referenced before set).

_cleanengine_ = True did not solve the issue in my (limited) testing.

If I manually wrap the script in a try:except and print traceback I can get the info I need for now, but it’s a bit of a hassle.

6

Dug into this over the last couple hours, looks like the issue (at least that I was seeing) was fixed in this pull request Fix/logging bug fixes by ChrisCrosley · Pull Request #3477 · pyrevitlabs/pyRevit
So, it’s fixed in the latest WIP version already.

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