Debug Template Errors - Nextedy Documentation

Prerequisites

A powersheet document with server-rendered properties configured
Access to Polarion server logs
Familiarity with Velocity template syntax

Recognize the Error Marker

When a Velocity template evaluation fails, Powersheet displays #SERVER_RENDER_ERROR in the affected cell instead of the computed value. This is a constant error marker that indicates a template configuration problem.

Check Polarion Server Logs

The three most common exception types appear in the Polarion server logs when a template fails:

Exception Type	Cause	Example
ParseErrorException	Invalid Velocity syntax	Missing `#end`, unbalanced quotes
MethodInvocationException	Method call on null or wrong type	`$item.getTitle()` when `$item` is null
ResourceNotFoundException	Referenced resource not found	Missing include or macro

Open the Polarion server log file and search for these exception names to find the exact error message and line number.

Validate Template Syntax

Common Velocity syntax errors that cause ParseErrorException:

# WRONG: Missing #end
serverRender: "#if($item.title)$item.title"

# CORRECT: Properly closed block
serverRender: "#if($item.title)$item.title#end"

# WRONG: Unescaped special characters
serverRender: "$item.title & $item.status"

# CORRECT: Escaped or avoided
serverRender: "$item.title and $item.status"

Server-rendered expressions are typically single-line strings in YAML. Multi-line Velocity logic must be compressed into one line or use Velocity’s inline syntax.

Add Null Checks

MethodInvocationException commonly occurs when accessing properties on null objects. Always guard against nulls:

# WRONG: Assumes $module is always available
serverRender: "$module.moduleName"

# CORRECT: Null check first
serverRender: "#if($module)$module.moduleName#else N/A#end"

Key variables that can be null:

$module — null when entity is not document-scoped
$wi — null when entity is not a work item
Custom field values — null when not set on the work item

Always wrap service calls and property access in #if checks: #if($var && $var.method())$var.method()#else default#end

Test with Simple Expressions First

When debugging a complex template, simplify to isolate the problem:

Replace your template with a constant: serverRender: "test" — verify rendering works at all
Add one variable: serverRender: "$item.id" — verify context is available
Add the failing expression piece by piece until the error reappears

Verify Property Configuration

Ensure the property hosting the server-rendered expression is correctly configured:

properties:
  computedField:
    serverRender: "$item.title"
    readable: true      # Must be true to display
    updatable: false     # Always false for server-rendered

Some Polarion service methods may behave differently across versions. If a method call in your template causes errors, verify the method signature against your Polarion installation’s API documentation.

Common Error Patterns

Symptom	Likely Cause	Fix
All rows show error	Template syntax error	Check for missing `#end` or bad directive
Some rows show error	Null data on specific items	Add null checks for optional fields
Error after Polarion upgrade	API change in service method	Update method calls to new API
Error on document entities only	`$wi` used on non-work-item	Use `$item` instead or add type check

Verify

After fixing template errors:

Open the powersheet document in Polarion
You should now see computed values in all cells that previously showed #SERVER_RENDER_ERROR
Test with work items that have empty or null fields to confirm null checks work
Verify that the Polarion server logs no longer show template-related exceptions

​Prerequisites

​Common Error Patterns

​Verify

​See Also

Prerequisites

Common Error Patterns

Verify

See Also