[Bug]: AttributeError: 'NoneType' object has no attribute 'replace' in 5.0.0-rc.2

[guenterw]

What is the bug?

When clicking on the button "Copy the drag and drop designer" (or when selecting "QGIS Drag&Drop form" as popup source) for a layer that has a field with a Value Map widget containing an entry without a value, the plugin crashes with:

AttributeError: 'NoneType' object has no attribute 'replace'

Traceback:

File "...\lizmap\plugin\core.py", line 1354, in maptip_from_form
  html_content = Tooltip.create_popup_node_item_from_form(
File "...\lizmap\tooltip.py", line 197, in create_popup_node_item_from_form
  h = Tooltip.create_popup_node_item_from_form(
File "...\lizmap\tooltip.py", line 125, in create_popup_node_item_from_form
  field_view = Tooltip._generate_value_map(widget_config, name)
File "...\lizmap\tooltip.py", line 306, in escape_value
  return value.replace("'", "'")
AttributeError: 'NoneType' object has no attribute 'replace'

Root cause: The affected field uses a Value Map widget in QGIS. One of its entries has no value at all, stored in the .qgs file as:

<Option type="invalid" name=" "/>

(type="invalid" is QGIS's internal representation for "no value", distinct from an empty string). This happens when a Value Map row is given a display label but the value column is left blank. _generate_value_map() builds row.items() from this config and calls escape_value() on every key and value without checking for None, causing the crash.

Steps to reproduce:

1. Add a field with widget type "Value Map" on a layer.
2. In the Value Map editor, add an entry with a label/description but leave the value empty.
3. Build a Drag&Drop attribute form including that field.
4. In the Lizmap plugin, open the layer's Popup configuration and either select "QGIS Drag&Drop form" or click "Copy the drag and drop designer".
5. The traceback above appears.

Expected behavior: escape_value() (and/or _generate_value_map()) should handle None values gracefully — e.g. treat them as an empty string — instead of crashing the whole popup/maptip generation.

Suggested fix:

def escape_value(value):
    if value is None:
        return ''
    return value.replace("'", "'")

Versions, safeguards, checks summary etc

Versions :

• Lizmap Web Client : 3.10.0-rc.3-pre.11635 - commit 4c86f09a0 3liz/lizmap-web-client@4c86f09a0
• Lizmap plugin : 5.0.0-rc.2
• QGIS Desktop : 3.44.12
• QGIS Server : 3.44.12
• Py-QGIS-Server : 1.9.6
• QGIS Server plugin atlasprint : 3.4.4
• QGIS Server plugin lizmap_server : 2.14.1
• QGIS Server plugin wfsOutputExtension : 1.8.3
• QGIS Server plugin wmsGetLegendGraphicTitle : 1.3

List of Lizmap Web Client modules :

* Version Lizmap Web Client 3.8 needed

List of safeguards :

* Mode : normal
* Allow parent folder : yes
* Number of parent : 4 folder(s)
* Prevent other drive : no
* Prevent PG service : no
* Prevent PG Auth DB : no
* Force PG user&pass : no
* Prevent ECW : yes

Check Lizmap plugin

• I have done the step just before in the Lizmap QGIS desktop plugin before opening this ticket. Otherwise, my ticket is not considered valid and might get closed.

[guenterw]

While looking for a way to display the plain QGIS Drag&Drop form in the Info panel/popup without showing NULL values, I came across the bug described above.

With the standard ("Automatic") popup, NULL values are ignored/hidden automatically. For the HTML table variant there is a corresponding option to exclude them. However, for the Drag&Drop form popup I couldn't find any way to achieve this without displaying the NULL values.

This is a separate topic from the crash above, so happy to open it as its own Feature Request if preferred — I just wanted to mention it here as context. I think this is actually a fairly important and common use case:
The Drag&Drop form is often used simply to control the field order in the popup, without needing anything more advanced — but it currently forces users to also accept NULL values being displayed, which the other popup variants avoid. I'd expect this to affect quite a few projects.