Error in export template silently causes the default export to be used instead

[candlerb]

NetBox version

v3.0.9

Python version

3.8

Steps to Reproduce

Create a new export template:

• Content Type: dcim | cable
• Name: Cables for CSV re-import
• Template as follows:

side_a_device,side_a_type,side_a_name,side_b_device,side_b_type,side_b_name,type,status,label,color,length,length_unit
{%- for c in queryset %}
{%- set lenitems = c.length.split(' ') %}
{{ c.termination_a.device.name }},
{{ c.termination_a_type.app_labeled_name }},{{ c.termination_a.name }},{{ c.termination_b.device.name }},
{{ c.termination_b_type.app_labeled_name }},{{ c.termination_b.name }},{{ c.type }},{{ c.status }},{{ c.label }},{{ lenitems[0] }},{{ lenitems[1] }}
{%- endfor %}

Now browse to cables, select a filter which limits them to a single device.

Click on Export > Cables for CSV Import

This links to dcim/cables/?q=&device_id=952&type=&status=&color=&export=Cables%20for%20CSV%20re-import

Expected Behavior

The downloaded CSV file would be formatted in accordance with the given template

OR: if the template is invalid, that an error would be reported.

Observed Behavior

The file netbox_cables.csv which is generated uses the default CSV formatting, ignoring the selected export template:

ID,Label,Side A,Termination A,Side B,Termination B,Status,Type,Length,Color,Tags
1791,,ldex-r17-sw1,PSU,PDU-R17-1,OUT24,Connected,Power,,,
1808,,ldex-r17-sw1,Gi1/0/24,mod-rj45-r17-r18-1-4,F1,Connected,CAT5e,50.00 Centimeters,#ffeb3b,
... etc

[candlerb]

If I change the template body to just

Hello World

then (1) the downloaded file is called netbox_cables instead of netbox_cables.csv, and (2) it has the selected content.

If I change the template body to

{%- for c in queryset %}
{{ c.id }}
{%- endfor %}

then netbox_cables contains a list of IDs. So I believe that I had some error in the original template, but this error was silently ignored and caused the default rendering to be used instead. If so, this isn't very helpful when trying to debug a template.

[candlerb]

Definitely the export template was bad. FWIW here's the debugged version:

side_a_device,side_a_type,side_a_name,side_b_device,side_b_type,side_b_name,type,status,label,color,length,length_unit
{%- for c in queryset %}
{%- if c.termination_a_type.app_label != 'circuits' and c.termination_b_type.app_label != 'circuits' %}
{{ c.termination_a.device.name }},{{ c.termination_a_type.app_labeled_name|replace(" | ",".")|replace(" ","") }},{{ c.termination_a.name }},{{ c.termination_b.device.name }},{{ c.termination_b_type.app_labeled_name|replace(" | ",".")|replace(" ","") }},{{ c.termination_b.name }},{{ c.type }},{{ c.status }},"{{ c.label }}",{{c.color}},{{ c.length|replace("None","") }},{{ c.length_unit }}
{%- endif %}
{%- endfor %}

But the point still stands: I think that broken export templates should generate errors when you try to use them.

[candlerb]

This might also be a browser-related issue. I'm using Chrome 95 under macOS 10.14.6.

I've just discovered that after the download has completed, if I switch to the "Filters" tab, change the filter, and switch back to the "Records" tab, I then see an error message:

However, the download did still complete (using the default export format)