tomighita commented on code in PR #2120: URL: https://github.com/apache/iceberg-rust/pull/2120#discussion_r2965672091
########## crates/iceberg/src/transaction/update_schema.rs: ########## @@ -0,0 +1,1137 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +use std::collections::{HashMap, HashSet}; +use std::sync::Arc; + +use async_trait::async_trait; +use typed_builder::TypedBuilder; + +use crate::spec::{ + ListType, Literal, MapType, NestedField, NestedFieldRef, Schema, StructType, Type, +}; +use crate::table::Table; +use crate::transaction::action::{ActionCommit, TransactionAction}; +use crate::{Error, ErrorKind, Result, TableRequirement, TableUpdate}; + +/// Sentinel parent ID representing the table root (top-level columns). +const TABLE_ROOT_ID: i32 = -1; +// Default ID for a new column. This will be re-assigned to a fresh ID at commit time. +const DEFAULT_ID: i32 = 0; + +#[derive(TypedBuilder)] +/// Declarative specification for adding a column in [`UpdateSchemaAction`]. +/// +/// Use helper constructors such as [`AddColumn::optional`] and [`AddColumn::required`], +/// optionally combined with [`AddColumn::with_parent`] and [`AddColumn::with_doc`], then pass +/// the value to +/// [`UpdateSchemaAction::add_column`]. +pub struct AddColumn { + #[builder(default = None, setter(strip_option, into))] + parent: Option<String>, + #[builder(setter(into))] + name: String, + #[builder(default = false)] + required: bool, + field_type: Type, + #[builder(default = None, setter(strip_option, into))] + doc: Option<String>, + #[builder(default = None, setter(strip_option))] + initial_default: Option<Literal>, + #[builder(default = None, setter(strip_option))] + write_default: Option<Literal>, +} + +impl AddColumn { + /// Create a root-level optional column specification. + pub fn optional(name: impl ToString, field_type: Type) -> Self { + Self::builder() + .name(name.to_string()) + .field_type(field_type) + .required(false) + .build() + } + + /// Create a root-level required column specification. + pub fn required(name: impl ToString, field_type: Type, initial_default: Literal) -> Self { + Self::builder() + .name(name.to_string()) + .field_type(field_type) + .required(true) + .initial_default(initial_default.clone()) + .write_default(initial_default) + .build() + } + + /// Return a copy with an updated parent path. + pub fn with_parent(mut self, parent: impl ToString) -> Self { + self.parent = Some(parent.to_string()); + self + } + + /// Return a copy with an updated doc string. + pub fn with_doc(mut self, doc: impl ToString) -> Self { + self.doc = Some(doc.to_string()); + self + } + + fn to_nested_field(&self) -> NestedFieldRef { + let mut field = NestedField::new( + DEFAULT_ID, + self.name.clone(), + self.field_type.clone(), + self.required, + ); + + field.doc = self.doc.clone(); + field.initial_default = self.initial_default.clone(); + field.write_default = self.write_default.clone(); + Arc::new(field) + } +} + +/// Schema evolution API modeled after the Java `SchemaUpdate` implementation. +/// +/// This action accumulates schema modifications (column additions and deletions) +/// via builder methods. At commit time, it validates all operations against the +/// current table schema, auto-assigns field IDs from `table.metadata().last_column_id()`, +/// builds a new schema, and emits `AddSchema` + `SetCurrentSchema` updates with a +/// `CurrentSchemaIdMatch` requirement. +/// +/// # Example +/// +/// ```ignore +/// let tx = Transaction::new(&table); +/// let action = tx.update_schema() +/// .add_column(AddColumn::optional("new_col", Type::Primitive(PrimitiveType::Int))) +/// .add_column( +/// AddColumn::optional("email", Type::Primitive(PrimitiveType::String)) +/// .with_parent("person") +/// ) +/// .delete_column("old_col"); +/// let tx = action.apply(tx).unwrap(); +/// let table = tx.commit(&catalog).await.unwrap(); +/// ``` +pub struct UpdateSchemaAction { + additions: Vec<AddColumn>, + deletes: Vec<String>, + auto_assign_ids: bool, +} + +impl UpdateSchemaAction { + /// Creates a new empty `UpdateSchemaAction`. + pub(crate) fn new() -> Self { + Self { + additions: Vec::new(), + deletes: Vec::new(), + auto_assign_ids: true, + } + } + + // --- Root-level additions --- + + /// Add a column to the table schema. + /// + /// To add a root-level column, leave `AddColumn::parent` as `None`. + /// For nested additions, set a parent path (for example via [`AddColumn::with_parent`]). + /// If the parent resolves to a map/list, the column is added to map value/list element. + pub fn add_column(mut self, add_column: AddColumn) -> Self { + self.additions.push(add_column); + self + } + + // --- Other builder methods --- + + /// Record a column deletion by name. + /// + /// At commit time, the column must exist in the current schema. + pub fn delete_column(mut self, name: impl ToString) -> Self { + self.deletes.push(name.to_string()); + self + } + + /// Disable automatic field ID assignment. When disabled, the placeholder IDs + /// provided in builder methods are used as-is. + pub fn disable_id_auto_assignment(mut self) -> Self { + self.auto_assign_ids = false; + self + } + + // --- Internal helpers --- +} + +// --------------------------------------------------------------------------- +// ID assignment helpers +// --------------------------------------------------------------------------- + +/// Recursively assign fresh field IDs to a `NestedField` and all its nested sub-fields. +/// +/// This follows the same recursive pattern as `ReassignFieldIds::reassign_ids_visit_type` +/// from `crate::spec::schema::id_reassigner`, but operates on new fields with placeholder +/// IDs rather than reassigning an existing schema. `ReassignFieldIds` cannot be used +/// directly here because it rejects duplicate old IDs (all new fields share placeholder +/// ID `DEFAULT_ID`). +fn assign_fresh_ids(field: &NestedField, next_id: &mut i32) -> NestedFieldRef { + *next_id += 1; + let new_id = *next_id; + let new_type = assign_fresh_ids_to_type(&field.field_type, next_id); + + Arc::new(NestedField { + id: new_id, + name: field.name.clone(), + required: field.required, + field_type: Box::new(new_type), + doc: field.doc.clone(), + initial_default: field.initial_default.clone(), + write_default: field.write_default.clone(), + }) +} + +/// Recursively assign fresh field IDs to all nested fields within a `Type`. +fn assign_fresh_ids_to_type(field_type: &Type, next_id: &mut i32) -> Type { + match field_type { + Type::Primitive(_) => field_type.clone(), + Type::Struct(struct_type) => { + let new_fields: Vec<NestedFieldRef> = struct_type + .fields() + .iter() + .map(|f| assign_fresh_ids(f, next_id)) + .collect(); + Type::Struct(StructType::new(new_fields)) + } + Type::List(list_type) => { + let new_element = assign_fresh_ids(&list_type.element_field, next_id); + Type::List(ListType { + element_field: new_element, + }) + } + Type::Map(map_type) => { + let new_key = assign_fresh_ids(&map_type.key_field, next_id); + let new_value = assign_fresh_ids(&map_type.value_field, next_id); + Type::Map(MapType { + key_field: new_key, + value_field: new_value, + }) + } + } +} + +// --------------------------------------------------------------------------- +// Parent path resolution +// --------------------------------------------------------------------------- + +/// Resolve a parent path to the target struct's parent field ID and a reference +/// to its `StructType`. +/// +/// If the parent is a map, navigates to the value field. If a list, navigates to +/// the element field. The final target must be a struct type. +fn resolve_parent_target<'a>( + base_schema: &'a Schema, + parent: &str, +) -> Result<(i32, &'a StructType)> { + base_schema + .field_by_name(parent) + .ok_or_else(|| { + Error::new( + ErrorKind::PreconditionFailed, + format!("Cannot add column: parent '{parent}' not found"), + ) + }) + .and_then(|parent_field| match parent_field.field_type.as_ref() { + Type::Struct(s) => Ok((parent_field.id, s)), + Type::Map(m) => match m.value_field.field_type.as_ref() { + Type::Struct(s) => Ok((m.value_field.id, s)), + _ => Err(Error::new( + ErrorKind::PreconditionFailed, + format!("Cannot add column: map value of '{parent}' is not a struct"), + )), + }, + Type::List(l) => match l.element_field.field_type.as_ref() { + Type::Struct(s) => Ok((l.element_field.id, s)), + _ => Err(Error::new( + ErrorKind::PreconditionFailed, + format!("Cannot add column: list element of '{parent}' is not a struct"), + )), + }, + _ => Err(Error::new( + ErrorKind::PreconditionFailed, + format!("Cannot add column: parent '{parent}' is not a struct, map, or list"), + )), + }) +} + +// --------------------------------------------------------------------------- +// Schema tree rebuild +// --------------------------------------------------------------------------- + +/// Rebuild a slice of fields, applying deletions and additions at every level, +/// plus any root-level additions keyed by `TABLE_ROOT_ID`. +fn rebuild_fields( + fields: &[NestedFieldRef], + adds: &HashMap<i32, Vec<NestedFieldRef>>, + delete_ids: &HashSet<i32>, + root_id: i32, +) -> Vec<NestedFieldRef> { + fields + .iter() + .filter(|f| !delete_ids.contains(&f.id)) + .map(|f| rebuild_field(f, adds, delete_ids)) + .chain(adds.get(&root_id).into_iter().flatten().cloned()) + .collect() +} + +/// Recursively rebuild a single field. If the field (or any descendant) is a struct +/// that has pending additions, those additions are appended to the struct's fields. +/// Fields whose IDs appear in `delete_ids` are filtered out at every struct level. +fn rebuild_field( + field: &NestedFieldRef, + adds: &HashMap<i32, Vec<NestedFieldRef>>, + delete_ids: &HashSet<i32>, +) -> NestedFieldRef { + match field.field_type.as_ref() { + Type::Primitive(_) => field.clone(), + Type::Struct(s) => { + let new_fields = rebuild_fields(s.fields(), adds, delete_ids, field.id); + Arc::new(NestedField { + id: field.id, + name: field.name.clone(), + required: field.required, + field_type: Box::new(Type::Struct(StructType::new(new_fields))), + doc: field.doc.clone(), + initial_default: field.initial_default.clone(), + write_default: field.write_default.clone(), + }) + } + Type::List(l) => { + let new_element = rebuild_field(&l.element_field, adds, delete_ids); + Arc::new(NestedField { + id: field.id, + name: field.name.clone(), + required: field.required, + field_type: Box::new(Type::List(ListType { + element_field: new_element, + })), + doc: field.doc.clone(), + initial_default: field.initial_default.clone(), + write_default: field.write_default.clone(), + }) + } + Type::Map(m) => { + let new_key = rebuild_field(&m.key_field, adds, delete_ids); + let new_value = rebuild_field(&m.value_field, adds, delete_ids); + Arc::new(NestedField { + id: field.id, + name: field.name.clone(), + required: field.required, + field_type: Box::new(Type::Map(MapType { + key_field: new_key, + value_field: new_value, + })), + doc: field.doc.clone(), + initial_default: field.initial_default.clone(), + write_default: field.write_default.clone(), + }) + } + } +} + +// --------------------------------------------------------------------------- +// TransactionAction implementation +// --------------------------------------------------------------------------- + +#[async_trait] +impl TransactionAction for UpdateSchemaAction { + async fn commit(self: Arc<Self>, table: &Table) -> Result<ActionCommit> { + let base_schema = table.metadata().current_schema(); + let mut last_column_id = table.metadata().last_column_id(); + + // --- 1. Validate deletes --- + let delete_ids = self + .deletes + .iter() + .map(|name: &String| { + base_schema + .field_by_name(name) + .ok_or_else(|| { + Error::new( + ErrorKind::PreconditionFailed, + format!("Cannot delete missing column: {name}"), + ) + }) + .and_then(|field| { + match base_schema + .identifier_field_ids() + .find(|id| *id == field.id) + { + Some(_) => Err(Error::new( + ErrorKind::PreconditionFailed, + format!("Cannot delete identifier field: {name}"), + )), + None => Ok(field.id), + } + }) + }) + .collect::<Result<HashSet<i32>>>()?; + + // --- 2. Resolve parents, validate additions, assign IDs, and group by parent ID --- + // We assign IDs inline (before grouping) to preserve the caller's insertion order, + // since HashMap iteration order is non-deterministic. + let mut additions_by_parent: HashMap<i32, Vec<NestedFieldRef>> = HashMap::new(); + + for add in &self.additions { + let pending_field = add.to_nested_field(); + + // Check that name does not contain ".". + if pending_field.name.contains('.') { + return Err(Error::new( + ErrorKind::PreconditionFailed, + format!( + "Cannot add column with ambiguous name: {}. Use `AddColumn::with_parent` to add a column to a nested struct.", + pending_field.name + ), + )); + } + + // Required columns without an initial default need allow_incompatible_changes. + if pending_field.required && pending_field.initial_default.is_none() { + return Err(Error::new( + ErrorKind::PreconditionFailed, + format!( + "Incompatible change: cannot add required column without an initial default: {}", + pending_field.name + ), + )); + } + + let parent_id = match &add.parent { + None => { + // Root-level: check name conflict against root-level fields. + if let Some(existing) = base_schema.field_by_name(&pending_field.name) + && !delete_ids.contains(&existing.id) + { + return Err(Error::new( + ErrorKind::PreconditionFailed, + format!( + "Cannot add column, name already exists: {}", + pending_field.name + ), + )); + } + TABLE_ROOT_ID + } + Some(parent_path) => { + // Nested: resolve parent, check name conflict within parent struct. + let (parent_id, parent_struct) = + resolve_parent_target(base_schema, parent_path)?; + + if parent_struct.fields().iter().any(|f| { + f.name == pending_field.name + && !delete_ids.contains(&f.id) + && !delete_ids.contains(&parent_id) + }) { + return Err(Error::new( + ErrorKind::PreconditionFailed, + format!( + "Cannot add column, name already exists in '{}': {}", + parent_path, pending_field.name + ), + )); + } + + parent_id + } + }; + + // Assign fresh IDs immediately, preserving insertion order. + let field = if self.auto_assign_ids { + assign_fresh_ids(&pending_field, &mut last_column_id) + } else { + pending_field + }; + + additions_by_parent + .entry(parent_id) + .or_default() + .push(field); + } + + // --- 4. Rebuild the schema tree with additions and deletions --- + let new_fields = rebuild_fields( + base_schema.as_struct().fields(), + &additions_by_parent, + &delete_ids, + TABLE_ROOT_ID, + ); + + // --- 5. Build the new schema --- + let schema = Schema::builder() + .with_fields(new_fields) + .with_identifier_field_ids(base_schema.identifier_field_ids()) + .build()?; + + let updates = vec![ + TableUpdate::AddSchema { schema }, + TableUpdate::SetCurrentSchema { schema_id: -1 }, + ]; + + let requirements = vec![TableRequirement::CurrentSchemaIdMatch { + current_schema_id: base_schema.schema_id(), + }]; + + Ok(ActionCommit::new(updates, requirements)) + } +} + +#[cfg(test)] +mod tests { + use std::io::BufReader; + use std::sync::Arc; + + use as_any::Downcast; + + use crate::spec::{Literal, NestedField, PrimitiveType, StructType, TableMetadata, Type}; + use crate::table::Table; + use crate::transaction::Transaction; + use crate::transaction::action::{ApplyTransactionAction, TransactionAction}; + use crate::transaction::tests::make_v2_table; + use crate::transaction::update_schema::{AddColumn, DEFAULT_ID, UpdateSchemaAction}; + use crate::{ErrorKind, TableIdent, TableRequirement, TableUpdate}; + + // The V2 test table has: + // last_column_id: 3 + // current schema (id=1): x(1, req, long), y(2, req, long), z(3, req, long) + // identifier_field_ids: [1, 2] + + /// Build a V2 test table that includes nested types: + /// + /// last_column_id: 14 + /// current schema (id=0): + /// x(1, req, long) -- identifier + /// y(2, req, long) -- identifier + /// z(3, req, long) + /// person(4, opt, struct) + /// name(5, opt, string) + /// age(6, req, int) + /// tags(7, opt, list<struct>) + /// element(8, req, struct) + /// key(9, opt, string) + /// value(10, opt, string) + /// props(11, opt, map<string, struct>) + /// key(12, req, string) + /// value(13, req, struct) + /// data(14, opt, string) + fn make_v2_table_with_nested() -> Table { + let json = r#"{ + "format-version": 2, + "table-uuid": "9c12d441-03fe-4693-9a96-a0705ddf69c2", + "location": "s3://bucket/test/location", + "last-sequence-number": 0, + "last-updated-ms": 1602638573590, + "last-column-id": 14, + "current-schema-id": 0, + "schemas": [ + { + "type": "struct", + "schema-id": 0, + "identifier-field-ids": [1, 2], + "fields": [ + {"id": 1, "name": "x", "required": true, "type": "long"}, + {"id": 2, "name": "y", "required": true, "type": "long"}, + {"id": 3, "name": "z", "required": true, "type": "long"}, + {"id": 4, "name": "person", "required": false, "type": { + "type": "struct", + "fields": [ + {"id": 5, "name": "name", "required": false, "type": "string"}, + {"id": 6, "name": "age", "required": true, "type": "int"} + ] + }}, + {"id": 7, "name": "tags", "required": false, "type": { + "type": "list", + "element-id": 8, + "element": { + "type": "struct", + "fields": [ + {"id": 9, "name": "key", "required": false, "type": "string"}, + {"id": 10, "name": "value", "required": false, "type": "string"} + ] + }, + "element-required": true + }}, + {"id": 11, "name": "props", "required": false, "type": { + "type": "map", + "key-id": 12, + "key": "string", + "value-id": 13, + "value": { + "type": "struct", + "fields": [ + {"id": 14, "name": "data", "required": false, "type": "string"} + ] + }, + "value-required": true + }} + ] + } + ], + "default-spec-id": 0, + "partition-specs": [ + {"spec-id": 0, "fields": []} + ], + "last-partition-id": 999, + "default-sort-order-id": 0, + "sort-orders": [ + {"order-id": 0, "fields": []} + ], + "properties": {}, + "current-snapshot-id": -1, + "snapshots": [] + }"#; + + let reader = BufReader::new(json.as_bytes()); + let metadata = serde_json::from_reader::<_, TableMetadata>(reader).unwrap(); + + Table::builder() + .metadata(metadata) + .metadata_location("s3://bucket/test/location/metadata/v1.json".to_string()) + .identifier(TableIdent::from_strs(["ns1", "test1"]).unwrap()) + .file_io(crate::io::FileIO::new_with_memory()) + .build() + .unwrap() + } + + // ----------------------------------------------------------------------- + // Existing root-level tests + // ----------------------------------------------------------------------- + + #[tokio::test] + async fn test_add_column() { + let table = make_v2_table(); + let tx = Transaction::new(&table); + + let action = tx.update_schema().add_column(AddColumn::optional( + "new_col", + Type::Primitive(PrimitiveType::Int), + )); + + let mut action_commit = Arc::new(action).commit(&table).await.unwrap(); + let updates = action_commit.take_updates(); + let requirements = action_commit.take_requirements(); + + assert_eq!(updates.len(), 2); + + // Extract the new schema from the AddSchema update. + let new_schema = match &updates[0] { + TableUpdate::AddSchema { schema } => schema, + other => panic!("expected AddSchema, got {other:?}"), + }; + + // The new field should have ID = last_column_id + 1 = 4. + let new_field = new_schema Review Comment: Done ########## crates/iceberg/src/transaction/update_schema.rs: ########## @@ -0,0 +1,1137 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +use std::collections::{HashMap, HashSet}; +use std::sync::Arc; + +use async_trait::async_trait; +use typed_builder::TypedBuilder; + +use crate::spec::{ + ListType, Literal, MapType, NestedField, NestedFieldRef, Schema, StructType, Type, +}; +use crate::table::Table; +use crate::transaction::action::{ActionCommit, TransactionAction}; +use crate::{Error, ErrorKind, Result, TableRequirement, TableUpdate}; + +/// Sentinel parent ID representing the table root (top-level columns). +const TABLE_ROOT_ID: i32 = -1; +// Default ID for a new column. This will be re-assigned to a fresh ID at commit time. +const DEFAULT_ID: i32 = 0; + +#[derive(TypedBuilder)] +/// Declarative specification for adding a column in [`UpdateSchemaAction`]. +/// +/// Use helper constructors such as [`AddColumn::optional`] and [`AddColumn::required`], +/// optionally combined with [`AddColumn::with_parent`] and [`AddColumn::with_doc`], then pass +/// the value to +/// [`UpdateSchemaAction::add_column`]. +pub struct AddColumn { + #[builder(default = None, setter(strip_option, into))] + parent: Option<String>, + #[builder(setter(into))] + name: String, + #[builder(default = false)] + required: bool, + field_type: Type, + #[builder(default = None, setter(strip_option, into))] + doc: Option<String>, + #[builder(default = None, setter(strip_option))] + initial_default: Option<Literal>, + #[builder(default = None, setter(strip_option))] + write_default: Option<Literal>, +} + +impl AddColumn { + /// Create a root-level optional column specification. + pub fn optional(name: impl ToString, field_type: Type) -> Self { + Self::builder() + .name(name.to_string()) + .field_type(field_type) + .required(false) + .build() + } + + /// Create a root-level required column specification. + pub fn required(name: impl ToString, field_type: Type, initial_default: Literal) -> Self { + Self::builder() + .name(name.to_string()) + .field_type(field_type) + .required(true) + .initial_default(initial_default.clone()) + .write_default(initial_default) + .build() + } + + /// Return a copy with an updated parent path. + pub fn with_parent(mut self, parent: impl ToString) -> Self { + self.parent = Some(parent.to_string()); + self + } + + /// Return a copy with an updated doc string. + pub fn with_doc(mut self, doc: impl ToString) -> Self { + self.doc = Some(doc.to_string()); + self + } + + fn to_nested_field(&self) -> NestedFieldRef { + let mut field = NestedField::new( + DEFAULT_ID, + self.name.clone(), + self.field_type.clone(), + self.required, + ); + + field.doc = self.doc.clone(); + field.initial_default = self.initial_default.clone(); + field.write_default = self.write_default.clone(); + Arc::new(field) + } +} + +/// Schema evolution API modeled after the Java `SchemaUpdate` implementation. +/// +/// This action accumulates schema modifications (column additions and deletions) +/// via builder methods. At commit time, it validates all operations against the +/// current table schema, auto-assigns field IDs from `table.metadata().last_column_id()`, +/// builds a new schema, and emits `AddSchema` + `SetCurrentSchema` updates with a +/// `CurrentSchemaIdMatch` requirement. +/// +/// # Example +/// +/// ```ignore +/// let tx = Transaction::new(&table); +/// let action = tx.update_schema() +/// .add_column(AddColumn::optional("new_col", Type::Primitive(PrimitiveType::Int))) +/// .add_column( +/// AddColumn::optional("email", Type::Primitive(PrimitiveType::String)) +/// .with_parent("person") +/// ) +/// .delete_column("old_col"); +/// let tx = action.apply(tx).unwrap(); +/// let table = tx.commit(&catalog).await.unwrap(); +/// ``` +pub struct UpdateSchemaAction { + additions: Vec<AddColumn>, + deletes: Vec<String>, + auto_assign_ids: bool, +} + +impl UpdateSchemaAction { + /// Creates a new empty `UpdateSchemaAction`. + pub(crate) fn new() -> Self { + Self { + additions: Vec::new(), + deletes: Vec::new(), + auto_assign_ids: true, + } + } + + // --- Root-level additions --- + + /// Add a column to the table schema. + /// + /// To add a root-level column, leave `AddColumn::parent` as `None`. + /// For nested additions, set a parent path (for example via [`AddColumn::with_parent`]). + /// If the parent resolves to a map/list, the column is added to map value/list element. + pub fn add_column(mut self, add_column: AddColumn) -> Self { + self.additions.push(add_column); + self + } + + // --- Other builder methods --- + + /// Record a column deletion by name. + /// + /// At commit time, the column must exist in the current schema. + pub fn delete_column(mut self, name: impl ToString) -> Self { + self.deletes.push(name.to_string()); + self + } + + /// Disable automatic field ID assignment. When disabled, the placeholder IDs + /// provided in builder methods are used as-is. + pub fn disable_id_auto_assignment(mut self) -> Self { + self.auto_assign_ids = false; + self + } + + // --- Internal helpers --- +} + +// --------------------------------------------------------------------------- +// ID assignment helpers +// --------------------------------------------------------------------------- + +/// Recursively assign fresh field IDs to a `NestedField` and all its nested sub-fields. +/// +/// This follows the same recursive pattern as `ReassignFieldIds::reassign_ids_visit_type` +/// from `crate::spec::schema::id_reassigner`, but operates on new fields with placeholder +/// IDs rather than reassigning an existing schema. `ReassignFieldIds` cannot be used +/// directly here because it rejects duplicate old IDs (all new fields share placeholder +/// ID `DEFAULT_ID`). +fn assign_fresh_ids(field: &NestedField, next_id: &mut i32) -> NestedFieldRef { + *next_id += 1; + let new_id = *next_id; + let new_type = assign_fresh_ids_to_type(&field.field_type, next_id); + + Arc::new(NestedField { + id: new_id, + name: field.name.clone(), + required: field.required, + field_type: Box::new(new_type), + doc: field.doc.clone(), + initial_default: field.initial_default.clone(), + write_default: field.write_default.clone(), + }) +} + +/// Recursively assign fresh field IDs to all nested fields within a `Type`. +fn assign_fresh_ids_to_type(field_type: &Type, next_id: &mut i32) -> Type { + match field_type { + Type::Primitive(_) => field_type.clone(), + Type::Struct(struct_type) => { + let new_fields: Vec<NestedFieldRef> = struct_type + .fields() + .iter() + .map(|f| assign_fresh_ids(f, next_id)) + .collect(); + Type::Struct(StructType::new(new_fields)) + } + Type::List(list_type) => { + let new_element = assign_fresh_ids(&list_type.element_field, next_id); + Type::List(ListType { + element_field: new_element, + }) + } + Type::Map(map_type) => { + let new_key = assign_fresh_ids(&map_type.key_field, next_id); + let new_value = assign_fresh_ids(&map_type.value_field, next_id); + Type::Map(MapType { + key_field: new_key, + value_field: new_value, + }) + } + } +} + +// --------------------------------------------------------------------------- +// Parent path resolution +// --------------------------------------------------------------------------- + +/// Resolve a parent path to the target struct's parent field ID and a reference +/// to its `StructType`. +/// +/// If the parent is a map, navigates to the value field. If a list, navigates to +/// the element field. The final target must be a struct type. +fn resolve_parent_target<'a>( + base_schema: &'a Schema, + parent: &str, +) -> Result<(i32, &'a StructType)> { + base_schema + .field_by_name(parent) + .ok_or_else(|| { + Error::new( + ErrorKind::PreconditionFailed, + format!("Cannot add column: parent '{parent}' not found"), + ) + }) + .and_then(|parent_field| match parent_field.field_type.as_ref() { + Type::Struct(s) => Ok((parent_field.id, s)), + Type::Map(m) => match m.value_field.field_type.as_ref() { + Type::Struct(s) => Ok((m.value_field.id, s)), + _ => Err(Error::new( + ErrorKind::PreconditionFailed, + format!("Cannot add column: map value of '{parent}' is not a struct"), + )), + }, + Type::List(l) => match l.element_field.field_type.as_ref() { + Type::Struct(s) => Ok((l.element_field.id, s)), + _ => Err(Error::new( + ErrorKind::PreconditionFailed, + format!("Cannot add column: list element of '{parent}' is not a struct"), + )), + }, + _ => Err(Error::new( + ErrorKind::PreconditionFailed, + format!("Cannot add column: parent '{parent}' is not a struct, map, or list"), + )), + }) +} + +// --------------------------------------------------------------------------- +// Schema tree rebuild +// --------------------------------------------------------------------------- + +/// Rebuild a slice of fields, applying deletions and additions at every level, +/// plus any root-level additions keyed by `TABLE_ROOT_ID`. +fn rebuild_fields( + fields: &[NestedFieldRef], + adds: &HashMap<i32, Vec<NestedFieldRef>>, + delete_ids: &HashSet<i32>, + root_id: i32, +) -> Vec<NestedFieldRef> { + fields + .iter() + .filter(|f| !delete_ids.contains(&f.id)) + .map(|f| rebuild_field(f, adds, delete_ids)) + .chain(adds.get(&root_id).into_iter().flatten().cloned()) + .collect() +} + +/// Recursively rebuild a single field. If the field (or any descendant) is a struct +/// that has pending additions, those additions are appended to the struct's fields. +/// Fields whose IDs appear in `delete_ids` are filtered out at every struct level. +fn rebuild_field( + field: &NestedFieldRef, + adds: &HashMap<i32, Vec<NestedFieldRef>>, + delete_ids: &HashSet<i32>, +) -> NestedFieldRef { + match field.field_type.as_ref() { + Type::Primitive(_) => field.clone(), + Type::Struct(s) => { + let new_fields = rebuild_fields(s.fields(), adds, delete_ids, field.id); + Arc::new(NestedField { + id: field.id, + name: field.name.clone(), + required: field.required, + field_type: Box::new(Type::Struct(StructType::new(new_fields))), + doc: field.doc.clone(), + initial_default: field.initial_default.clone(), + write_default: field.write_default.clone(), + }) + } + Type::List(l) => { + let new_element = rebuild_field(&l.element_field, adds, delete_ids); + Arc::new(NestedField { + id: field.id, + name: field.name.clone(), + required: field.required, + field_type: Box::new(Type::List(ListType { + element_field: new_element, + })), + doc: field.doc.clone(), + initial_default: field.initial_default.clone(), + write_default: field.write_default.clone(), + }) + } + Type::Map(m) => { + let new_key = rebuild_field(&m.key_field, adds, delete_ids); + let new_value = rebuild_field(&m.value_field, adds, delete_ids); + Arc::new(NestedField { + id: field.id, + name: field.name.clone(), + required: field.required, + field_type: Box::new(Type::Map(MapType { + key_field: new_key, + value_field: new_value, + })), + doc: field.doc.clone(), + initial_default: field.initial_default.clone(), + write_default: field.write_default.clone(), + }) + } + } +} + +// --------------------------------------------------------------------------- +// TransactionAction implementation +// --------------------------------------------------------------------------- + +#[async_trait] +impl TransactionAction for UpdateSchemaAction { + async fn commit(self: Arc<Self>, table: &Table) -> Result<ActionCommit> { + let base_schema = table.metadata().current_schema(); + let mut last_column_id = table.metadata().last_column_id(); + + // --- 1. Validate deletes --- + let delete_ids = self + .deletes + .iter() + .map(|name: &String| { + base_schema + .field_by_name(name) + .ok_or_else(|| { + Error::new( + ErrorKind::PreconditionFailed, + format!("Cannot delete missing column: {name}"), + ) + }) + .and_then(|field| { + match base_schema + .identifier_field_ids() + .find(|id| *id == field.id) + { + Some(_) => Err(Error::new( + ErrorKind::PreconditionFailed, + format!("Cannot delete identifier field: {name}"), + )), + None => Ok(field.id), + } + }) + }) + .collect::<Result<HashSet<i32>>>()?; + + // --- 2. Resolve parents, validate additions, assign IDs, and group by parent ID --- + // We assign IDs inline (before grouping) to preserve the caller's insertion order, + // since HashMap iteration order is non-deterministic. + let mut additions_by_parent: HashMap<i32, Vec<NestedFieldRef>> = HashMap::new(); + + for add in &self.additions { + let pending_field = add.to_nested_field(); + + // Check that name does not contain ".". + if pending_field.name.contains('.') { Review Comment: Done -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
