CTE in view is lost during planning when CASE is used

[whoward]

Here's another oddball issue in planning. Given the following database:

create table some_table(
  id serial primary key,
  start_date date,
  report_date date,
  type varchar(20)
);

CREATE VIEW some_view AS
WITH months AS (
  select generate_series as start_date from generate_series('2025-03-01'::date, NOW()::date, '1 month')
)
SELECT
  CASE
    WHEN (some_table.type IS NULL) THEN some_table.report_date
    ELSE NULL::date
  END AS previous_report_date
  FROM some_table
     JOIN months month ON month.start_date = some_table.start_date
  ;

pgschema dump will produce the correct output:

--
-- pgschema database dump
--

-- Dumped from database version PostgreSQL 17.0
-- Dumped by pgschema version 1.4.0


--
-- Name: some_table; Type: TABLE; Schema: -; Owner: -
--

CREATE TABLE IF NOT EXISTS some_table (
    id SERIAL,
    start_date date,
    report_date date,
    type varchar(20),
    CONSTRAINT some_table_pkey PRIMARY KEY (id)
);

--
-- Name: some_view; Type: VIEW; Schema: -; Owner: -
--

CREATE OR REPLACE VIEW some_view AS
 WITH months AS (
         SELECT generate_series.generate_series AS start_date
           FROM generate_series('2025-03-01'::date::timestamp with time zone, now()::date::timestamp with time zone, '1 mon'::interval) generate_series(generate_series)
        )
 SELECT
        CASE
            WHEN some_table.type IS NULL THEN some_table.report_date
            ELSE NULL::date
        END AS previous_report_date
   FROM some_table
     JOIN months month ON month.start_date = some_table.start_date;

However when we feed this back into pgschema plan --file dump.sql we get the following plan:

Plan: 1 to modify.

Summary by type:
  views: 1 to modify

Views:
  ~ some_view

DDL to be executed:
--------------------------------------------------

CREATE OR REPLACE VIEW some_view AS
 SELECT
    CASE WHEN some_table.type IS NULL THEN some_table.report_date ELSE NULL END AS previous_report_date
   FROM some_table
     JOIN months month ON month.start_date = some_table.start_date;

It seems the planner has stripped out the CTE for some reason

[whoward]

just tested and this works great, thanks!