sql: inherit declared schema in materialized view replacements

misc/python/materialize/checks/all_checks/materialized_views.py

@@ -440,11 +440,13 @@ def manipulate(self) -> list[Testdrive]:
                 """
                 > INSERT INTO mv_declared_table VALUES (3, 'z')
                 > CREATE MATERIALIZED VIEW mv_declared_schema2 (a int4 NOT NULL, b text) AS SELECT a, b FROM mv_declared_table
+                > CREATE REPLACEMENT MATERIALIZED VIEW mv_declared_replacement1 FOR mv_declared_schema1 AS SELECT a::int8, count(*) * 10 FROM mv_declared_table WHERE a IS NOT NULL GROUP BY a::int8
                 """,
                 """
                 > INSERT INTO mv_declared_table VALUES (4, 'w')
-                > CREATE REPLACEMENT MATERIALIZED VIEW mv_declared_replacement (k int8 NOT NULL, n int8) FOR mv_declared_schema1 AS SELECT a, count(*) * 10 FROM mv_declared_table WHERE a IS NOT NULL GROUP BY a
-                > ALTER MATERIALIZED VIEW mv_declared_schema1 APPLY REPLACEMENT mv_declared_replacement
+                > ALTER MATERIALIZED VIEW mv_declared_schema1 APPLY REPLACEMENT mv_declared_replacement1
+                > CREATE REPLACEMENT MATERIALIZED VIEW mv_declared_replacement2 (a int4 NOT NULL, b text) FOR mv_declared_schema2 AS SELECT a, upper(b) FROM mv_declared_table
+                > ALTER MATERIALIZED VIEW mv_declared_schema2 APPLY REPLACEMENT mv_declared_replacement2
                 """,
             ]
         ]
@@ -458,10 +460,10 @@ def validate(self) -> Testdrive:
                 4 10
 
                 > SELECT * FROM mv_declared_schema2
-                1 x
+                1 X
                 2 <null>
-                3 z
-                4 w
+                3 Z
+                4 W
 
                 > SELECT name, nullable, type FROM (SHOW COLUMNS FROM mv_declared_schema1)
                 k false bigint

src/adapter/src/coord/command_handler.rs

@@ -45,7 +45,8 @@ use mz_sql::plan::{
     StatementClassification, TransactionType,
 };
 use mz_sql::pure::{
-    materialized_view_option_contains_temporal, purify_create_materialized_view_options,
+    materialized_view_option_contains_temporal, purify_create_materialized_view_columns,
+    purify_create_materialized_view_options,
 };
 use mz_sql::rbac;
 use mz_sql::session::hint::ApplicationNameHint;
@@ -1732,6 +1733,11 @@ impl Coordinator {
 
                 let catalog = self.catalog().for_session(ctx.session());
 
+                if let Err(e) =
+                    purify_create_materialized_view_columns(&catalog, &mut cmvs, &mut resolved_ids)
+                {
+                    return ctx.retire(Err(e.into()));
+                }
                 purify_create_materialized_view_options(
                     catalog,
                     mz_now,
@@ -1779,6 +1785,11 @@ impl Coordinator {
 
                 let catalog = self.catalog().for_session(ctx.session());
 
+                if let Err(e) =
+                    purify_create_materialized_view_columns(&catalog, &mut cmvs, &mut resolved_ids)
+                {
+                    return ctx.retire(Err(e.into()));
+                }
                 purify_create_materialized_view_options(
                     catalog,
                     mz_now,

src/adapter/src/error.rs

@@ -851,8 +851,8 @@ impl AdapterError {
                     .to_string(),
             ),
             AdapterError::ReplacementSchemaNotDeclared => Some(
-                "Declare the target's columns with their types. EXPLAIN ... WITH (schema) prints \
-                them for the target."
+                "Omit the column list to use the target's column definitions, or declare the \
+                columns with their types."
                     .to_string(),
             ),
             AdapterError::SubscribeFellBehind { .. } => Some(

src/sql/src/pure.rs

@@ -44,7 +44,7 @@ use mz_sql_parser::ast::{
     CsrConfigOptionName, CsrConnection, CsrSeedAvro, CsrSeedProtobuf, CsrSeedProtobufSchema,
     DeferredItemName, DocOnIdentifier, DocOnSchema, Expr, Function, FunctionArgs, GlueAvroOption,
     GlueAvroSeed, Ident, KafkaSourceConfigOption, KafkaSourceConfigOptionName, LoadGenerator,
-    LoadGeneratorOption, LoadGeneratorOptionName, MaterializedViewOption,
+    LoadGeneratorOption, LoadGeneratorOptionName, MaterializedViewColumns, MaterializedViewOption,
     MaterializedViewOptionName, MySqlConfigOption, MySqlConfigOptionName, PgConfigOption,
     PgConfigOptionName, RawItemName, ReaderSchemaSelectionStrategy, RefreshAtOptionValue,
     RefreshEveryOptionValue, RefreshOptionValue, SourceEnvelope, SqlServerConfigOption,
@@ -2949,6 +2949,45 @@ async fn compile_proto(
     })
 }
 
+/// Gives a replacement materialized view without a column list the column
+/// definitions of its target, if the target declares its schema.
+///
+/// Writing the definitions into the statement keeps the replacement's
+/// `create_sql` self-contained, so re-planning it does not depend on the
+/// target, and records dependencies on the types the definitions use. Applying
+/// the replacement copies its column list to the target, which keeps the
+/// target's schema declared.
+pub fn purify_create_materialized_view_columns(
+    catalog: &dyn SessionCatalog,
+    cmvs: &mut CreateMaterializedViewStatement<Aug>,
+    resolved_ids: &mut ResolvedIds,
+) -> Result<(), PlanError> {
+    // Planning reports a missing or invalid replacement target.
+    let Some(ResolvedItemName::Item { id, .. }) = &cmvs.replacement_for else {
+        return Ok(());
+    };
+    if !cmvs.columns.is_empty() {
+        return Ok(());
+    }
+    let target = catalog.get_item(id);
+    let stmt = mz_sql_parser::parser::parse_statements(target.create_sql())?
+        .into_element()
+        .ast;
+    let Statement::CreateMaterializedView(target_stmt) = stmt else {
+        return Ok(());
+    };
+    if !matches!(
+        target_stmt.columns,
+        MaterializedViewColumns::Definitions { .. }
+    ) {
+        return Ok(());
+    }
+    let (columns, ids) = crate::names::resolve(catalog, target_stmt.columns)?;
+    cmvs.columns = columns;
+    resolved_ids.extend_from(&ids);
+    Ok(())
+}
+
 const MZ_NOW_NAME: &str = "mz_now";
 const MZ_NOW_SCHEMA: &str = "mz_catalog";
 

test/sqllogictest/materialized_view_declared_schema.slt

@@ -279,7 +279,7 @@ q  text
 
 # Replacements are compared against the declared schema.
 statement error replacement must declare its schema because its target does
-CREATE REPLACEMENT MATERIALIZED VIEW rp FOR mv AS SELECT a::int8 AS x, b AS y, c::numeric(10, 1) AS z FROM t
+CREATE REPLACEMENT MATERIALIZED VIEW rp (x, y, z) FOR mv AS SELECT a::int8, b, c::numeric(10, 1) FROM t
 
 statement error replacement schema differs from target schema
 CREATE REPLACEMENT MATERIALIZED VIEW rp (x int8, y text, z numeric(10, 1)) FOR mv AS SELECT a, b, c::numeric(10, 1) FROM t
@@ -301,6 +301,70 @@ SELECT create_sql LIKE '%("x" %int8% NOT NULL, "y" %text%, "z" %numeric%10%1%)%'
 ----
 true
 
+# A replacement without a column list gets the target's column definitions,
+# including names, and is cast to them as if they were written out.
+statement error materialized view materialize.public.rp declares 3 columns, but its query produces 2
+CREATE REPLACEMENT MATERIALIZED VIEW rp FOR mv AS SELECT a::int8, b FROM t
+
+# Inherited types are cast to with implicit casts only.
+statement error column "z" is of type numeric but expression is of type numeric with different type modifiers
+CREATE REPLACEMENT MATERIALIZED VIEW rp FOR mv AS SELECT a::int8, b, c FROM t
+
+statement ok
+CREATE REPLACEMENT MATERIALIZED VIEW rp FOR mv AS SELECT a * 10 AS ignored, b, c::numeric(10, 1) FROM t
+
+query TTT rowsort
+SELECT name, nullable, type FROM (SHOW COLUMNS FROM rp)
+----
+x  false  bigint
+y  true  text
+z  true  numeric
+
+query T
+SELECT create_sql LIKE '%("x" %int8% NOT NULL, "y" %text%, "z" %numeric%10%1%)%' FROM mz_materialized_views WHERE name = 'rp'
+----
+true
+
+statement ok
+ALTER MATERIALIZED VIEW mv APPLY REPLACEMENT rp
+
+query ITR rowsort
+SELECT * FROM mv
+----
+10  x  1.2
+20  y  2.5
+
+query T
+SELECT create_sql LIKE '%("x" %int8% NOT NULL, "y" %text%, "z" %numeric%10%1%)%' FROM mz_materialized_views WHERE name = 'mv'
+----
+true
+
+# Types used by inherited column definitions are dependencies, also after the
+# replacement is applied.
+statement ok
+CREATE TYPE int4_list AS LIST (ELEMENT TYPE = int4)
+
+statement ok
+CREATE VIEW lists AS SELECT LIST[a]::int4_list AS l FROM t
+
+statement ok
+CREATE MATERIALIZED VIEW mv_typed (l int4_list) AS SELECT l FROM lists
+
+statement ok
+CREATE REPLACEMENT MATERIALIZED VIEW rp FOR mv_typed AS SELECT l FROM lists
+
+statement ok
+ALTER MATERIALIZED VIEW mv_typed APPLY REPLACEMENT rp
+
+query I
+SELECT count(*)
+FROM mz_internal.mz_object_dependencies d
+JOIN mz_materialized_views m ON d.object_id = m.id
+JOIN mz_types ty ON d.referenced_object_id = ty.id
+WHERE m.name = 'mv_typed' AND ty.name = 'int4_list'
+----
+1
+
 # An implicit target can be given a declared schema that matches its current
 # one.
 statement ok