Add warning log with file path for missing event handler function

[Copilot]

Empty event handler files cause a cryptic Function.prototype.apply was called on undefined error without indicating which file is problematic.

Changes

• Log a warning with the file path when an event handler lacks a valid default export
• Skip invalid handlers with continue to prevent runtime errors

Before/After

// Before: error without file path, handler still added to listeners
if (!handler.default || typeof handler.default !== 'function') {
  Logger.error`Event handler for ${event.event}... does not have a default export...`;
}
listeners.push({ handler: handler.default, ... });  // undefined handler added

// After: warning with file path, invalid handler skipped
if (!handler.default || typeof handler.default !== 'function') {
  Logger.warn`Event handler for ${event.event}... at "${listener}" does not have a default export... Skipping...`;
  continue;
}

Original prompt

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This section details on the original issue you should resolve

<issue_title>Empty file causes an error but CK doesn't give enough info about the error</issue_title>
<issue_description> [ERROR] │ 00:03:40.619 └ Error handling event clientReady: Function.prototype.apply was called on undefined, which is a undefined and not a function
Leaving a file empty (happens rarely when I comment everything out for testing purposes or if it needs something to be fixed later on etc.) causes CK to throw errors but it doesn't tell the user which file the problem is in.</issue_description>

<agent_instructions>This is caused by event handler trying to execute the event function without checking if that function exists and is valid. Add a warning log if the event function is missing when executing the event so that dev is aware of the issue. Only make this change and do not try to build or test the code.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes Empty file causes an error but CK doesn't give enough info about the error #606

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1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
commandkit	Ignored	Preview	Feb 2, 2026 3:16pm