ID 472451 - Some expression syntax, when set on a knob, will cause the .hrox file to be written out as invalid XML

Problem summary

Some expression syntax, when set on a knob, will cause the .hrox file to be written out as invalid XML.

If you try to open one of these projects, the Loading project progress dialog stays at 0% indefinitely.  

Customer reported version
Nuke 12.2v3

Customer reported platform
Windows 10

Steps to reproduce

1) Add the following lines of code to your menu.py or init.py file:

def getVersionFromReadNode():
    return '[if {[string first \"v\" [value file]]>-1} {return [string range [value file] [expr [string first \"v\" [value file]]+1] [expr [string first \"v\" [value file]]+3]]} {return \"No Version\"}]'

nuke.knobDefault('Read.label', getVersionFromReadNode()) 

This will add the expression as a knob default for the label knob on all Read nodes. While this knob is not exposed in Nuke Studio's GUI, its value is still written into the .hrox file.

2) Open Nuke Studio.

3) Import a clip (File > Import File(s)...).

4) Save the project (File > Save Project As).

5) Close the project (File > Close Project).

6) Try to reopen the project (File > Open Project...).

Expected behaviour
Nuke Studio should not write out .hrox files that it can't open again.

Actual behaviour
Some expression syntax, when set on a knob, will cause the .hrox file to be written out as invalid XML.

If you try to open one of these projects, the Loading project progress dialog stays at 0% indefinitely.  

Workaround
In this case, you can open the .hrox file in a text editor and change the following syntax:

[value file]]>-1

To include extra spaces, like so:

[value file]] > -1

Reproduced by support

This bug has been reproduced in:
Nuke Studio 13.0v1 - Windows 10 - Linux CentOS 7 - macOS 10.13 (High Sierra)

Nuke Studio 12.0v1 - Windows 10

Nuke Studio 11.1v1 - Windows 10 - Linux CentOS 7 - macOS 10.13 (High Sierra) - Regression

Unable to reproduce bug in:
Nuke Studio 11.0v4 - Windows 10 - Linux CentOS 7 - macOS 10.13 (High Sierra)

Earliest version tested
Nuke Studio 11.0v4
- This issue doesn't appear in this version and has regressed