Views that call functions are not ordered after those functions

Start with GetViews and view_sql_generator.go, then inspect the View struct and the existing TableDependencies flow. Use the supplied function-and-view reproducer to verify dependency discovery and ordering. Done means the function is created before the view in the generated plan, without the current PostgreSQL error.

Views that call functions are not ordered after those functions

pg-schema-diff version

v1.0.5

Problem

A view definition can call a function:

CREATE FUNCTION fn_compute(id integer) RETURNS TABLE(result text) ...;
CREATE VIEW v_computed AS SELECT * FROM fn_compute(42);

pg-schema-diff does not track this dependency. The view may be created before the function, causing:

ERROR: function fn_compute(integer) does not exist (SQLSTATE 42883)

Root cause

The view vertex generator (view_sql_generator.go) only wires dependencies on tables (via TableDependencies). It has no awareness of function dependencies.

PostgreSQL does track view→function dependencies in pg_depend (via the view's rewrite rule), so the information is available:

SELECT pg_proc.proname, proc_ns.nspname,
       pg_catalog.pg_get_function_identity_arguments(pg_proc.oid)
FROM pg_catalog.pg_depend AS d
JOIN pg_catalog.pg_rewrite AS r ON d.objid = r.oid AND r.ev_class = <view_oid>
JOIN pg_catalog.pg_depend AS d2 ON r.oid = d2.objid
JOIN pg_catalog.pg_proc ON d2.refobjid = pg_proc.oid AND d2.refclassid = 'pg_proc'::REGCLASS
JOIN pg_catalog.pg_namespace AS proc_ns ON pg_proc.pronamespace = proc_ns.oid
WHERE d.refobjid = <view_oid> AND d2.deptype = 'n'
  AND proc_ns.nspname NOT IN ('pg_catalog', 'information_schema');

Suggested fix

1. Add a function_dependencies column to GetViews (similar query to above)
2. Add DependsOnFunctions []SchemaQualifiedName to the View struct
3. In view_sql_generator.go Add(), wire: mustRun(addVertexId).after(buildFunctionVertexId(f, diffTypeAddAlter))

Reproducer

CREATE FUNCTION public.fn_helper() RETURNS TABLE(x int) LANGUAGE sql AS $$ SELECT 1; $$;
CREATE VIEW public.v_uses_fn AS SELECT * FROM public.fn_helper();

Plan from empty → target: view is ordered before function → apply fails.

Related

• #248 (function dependency ordering)