Frappe Hooks Error Diagnosis & Resolution

Cross-ref: frappe-syntax-hooks (syntax), frappe-impl-hooks (workflows), frappe-errors-controllers (controller errors).

Error-to-Fix Mapping Table

Error / Symptom	Cause	Fix
Hook not firing at all	Typo in dotted path	Verify module path matches actual file location
`ImportError` on bench start	Wrong module path or circular import	Fix import path; break circular dependency
`AttributeError: module has no attribute`	Function name typo in hooks.py	Match function name exactly to Python definition
`app_include_js` not loading	Path missing `assets/` prefix or wrong extension	Use `"assets/myapp/js/file.js"` format
scheduler_events not running	Scheduler disabled or workers down	`bench scheduler enable`, check `bench doctor`
doc_events handler never called	DocType name misspelled in dict key	Use exact DocType name with spaces: `"Sales Invoice"`
`permission_query_conditions` breaks list view	SQL syntax error or frappe.throw() in handler	Return valid SQL string; NEVER throw
`override_doctype_class` import failure	Parent class import path changed between versions	Pin import to correct module path for target version
`extend_doctype_class` [v16+] method conflict	Two extensions define same method name	Rename conflicting methods; check hook resolution order