Tidy up metadata resolve (#527)

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## Description

This stacks on top of hasura/v3-engine#526 and
is the tidying up step following it.

There is a lot going on here, none of it particularly interesting.

- We remove the old `resolve_metadata` function, so all of "the action"
for resolving metadata happens inside `resolved::stages::mod`.
- We move the remaining modules into two folders, `helpers` and `types`.
This is a pretty rough cut, and there are definitely better homes for
the things here, I just wanted the separation of stages and "other bits"
to be clearer.
- We split the `types` helpers into `types` and `type_mappings`, as the
`type_mappings` stuff was clearly defined and didn't belong with the
grab-bag of functions that remain in `types`.
- We explicitly export everything used outside metadata resolve, and
stop other modules dipping into it's internal structure. This will make
future changes (particularly refactors that change the stages etc) a lot
easier as we don't need the rest of the app concerning itself with it.
- I _think_ we may now be able to move metadata resolve into a separate
crate. I have not tried yet, this PR is already silly enough.

When given a choice between "fixing" something, and doing the most
mechanical obvious change, I have opted for the latter. That is to
derisk this big change, and to ensure it doesn't linger, collecting
awful merge conflicts.

Functional no-op.

V3_GIT_ORIGIN_REV_ID: 2b52403cbfddb0427b8a3e61ad2edaef9d1b3b46

v3/crates/engine/src/build.rs

@@ -7,7 +7,7 @@ use thiserror::Error;
 #[derive(Error, Debug)]
 pub enum BuildError {
     #[error("invalid metadata: {0}")]
-    InvalidMetadata(#[from] metadata::resolved::error::Error),
+    InvalidMetadata(#[from] metadata::resolved::Error),
     #[error("unable to build schema: {0}")]
     UnableToBuildSchema(#[from] schema::Error),
     #[error("unable to encode schema: {0}")]

v3/crates/engine/src/execute/error.rs

@@ -12,7 +12,7 @@ use tracing_util::{ErrorVisibility, TraceableError};
 use transitive::Transitive;
 
 use crate::execute::ndc::client as ndc_client;
-use crate::metadata::resolved::{ndc_validation::NDCValidationError, subgraph::Qualified};
+use crate::metadata::resolved::{NDCValidationError, Qualified};
 
 use super::types::{Annotation, NamespaceAnnotation};
 

v3/crates/engine/src/execute/explain.rs

@@ -186,7 +186,7 @@ async fn get_execution_steps<'s>(
     process_response_as: &ProcessResponseAs<'s>,
     join_locations: JoinLocations<(RemoteJoin<'s, '_>, JoinId)>,
     ndc_request: types::NDCRequest,
-    data_connector: &resolved::stages::data_connectors::DataConnectorLink,
+    data_connector: &resolved::DataConnectorLink,
 ) -> NonEmpty<Box<types::Step>> {
     let mut sequence_steps = match process_response_as {
         ProcessResponseAs::CommandResponse { .. } => {
@@ -304,7 +304,7 @@ fn simplify_step(step: Box<types::Step>) -> Box<types::Step> {
 async fn fetch_explain_from_data_connector(
     http_context: &HttpContext,
     ndc_request: &types::NDCRequest,
-    data_connector: &resolved::stages::data_connectors::DataConnectorLink,
+    data_connector: &resolved::DataConnectorLink,
 ) -> types::NDCExplainResponse {
     let tracer = tracing_util::global_tracer();
     let response = tracer

v3/crates/engine/src/execute/ir/arguments.rs

@@ -9,10 +9,10 @@ use open_dds::types::{CustomTypeName, InbuiltType};
 
 use crate::execute::error;
 use crate::execute::ir::arguments;
-use crate::metadata::resolved::subgraph::{
+use crate::metadata::resolved::TypeMapping;
+use crate::metadata::resolved::{
     Qualified, QualifiedBaseType, QualifiedTypeName, QualifiedTypeReference,
 };
-use crate::metadata::resolved::TypeMapping;
 use crate::schema::types::{
     Annotation, ArgumentNameAndPath, ArgumentPresets, InputAnnotation, ModelInputAnnotation,
 };

v3/crates/engine/src/execute/ir/commands.rs

@@ -21,8 +21,7 @@ use crate::execute::error;
 use crate::execute::ir::permissions;
 use crate::execute::model_tracking::{count_command, UsagesCounts};
 use crate::metadata::resolved;
-use crate::metadata::resolved::subgraph;
-use crate::metadata::resolved::subgraph::QualifiedTypeReference;
+use crate::metadata::resolved::{Qualified, QualifiedTypeReference};
 use crate::schema::types::ArgumentNameAndPath;
 use crate::schema::types::ArgumentPresets;
 use crate::schema::types::CommandSourceDetail;
@@ -33,13 +32,13 @@ use crate::schema::GDS;
 #[derive(Serialize, Debug)]
 pub struct CommandInfo<'s> {
     /// The name of the command
-    pub command_name: subgraph::Qualified<commands::CommandName>,
+    pub command_name: Qualified<commands::CommandName>,
 
     /// The name of the field as published in the schema
     pub field_name: ast::Name,
 
     /// The data connector backing this model.
-    pub data_connector: &'s resolved::stages::data_connectors::DataConnectorLink,
+    pub data_connector: &'s resolved::DataConnectorLink,
 
     /// Arguments for the NDC table
     pub(crate) arguments: BTreeMap<String, json::Value>,
@@ -81,7 +80,7 @@ pub struct ProcedureBasedCommand<'s> {
 /// Generates the IR for a 'command' operation
 #[allow(irrefutable_let_patterns)]
 pub(crate) fn generate_command_info<'n, 's>(
-    command_name: &subgraph::Qualified<commands::CommandName>,
+    command_name: &Qualified<commands::CommandName>,
     field: &'n normalized_ast::Field<'s, GDS>,
     field_call: &'n normalized_ast::FieldCall<'s, GDS>,
     result_type: &QualifiedTypeReference,
@@ -174,7 +173,7 @@ pub(crate) fn generate_command_info<'n, 's>(
 
 /// Generates the IR for a 'function based command' operation
 pub(crate) fn generate_function_based_command<'n, 's>(
-    command_name: &subgraph::Qualified<commands::CommandName>,
+    command_name: &Qualified<commands::CommandName>,
     function_name: &'s open_dds::commands::FunctionName,
     field: &'n normalized_ast::Field<'s, GDS>,
     field_call: &'n normalized_ast::FieldCall<'s, GDS>,
@@ -202,7 +201,7 @@ pub(crate) fn generate_function_based_command<'n, 's>(
 
 /// Generates the IR for a 'procedure based command' operation
 pub(crate) fn generate_procedure_based_command<'n, 's>(
-    command_name: &subgraph::Qualified<commands::CommandName>,
+    command_name: &Qualified<commands::CommandName>,
     procedure_name: &'s open_dds::commands::ProcedureName,
     field: &'n normalized_ast::Field<'s, GDS>,
     field_call: &'n normalized_ast::FieldCall<'s, GDS>,

v3/crates/engine/src/execute/ir/model_selection.rs

@@ -14,14 +14,14 @@ use super::selection_set;
 use crate::execute::error;
 use crate::execute::model_tracking::UsagesCounts;
 use crate::metadata::resolved;
-use crate::metadata::resolved::subgraph::Qualified;
+use crate::metadata::resolved::Qualified;
 use crate::schema::GDS;
 
 /// IR fragment for any 'select' operation on a model
 #[derive(Debug, Serialize)]
 pub struct ModelSelection<'s> {
     // The data connector backing this model.
-    pub data_connector: &'s resolved::stages::data_connectors::DataConnectorLink,
+    pub data_connector: &'s resolved::DataConnectorLink,
 
     // Source collection in the data connector for this model
     pub(crate) collection: &'s String,

v3/crates/engine/src/execute/ir/permissions.rs

@@ -10,9 +10,7 @@ use crate::execute::error::{Error, InternalDeveloperError, InternalEngineError,
 use crate::execute::model_tracking::{count_model, UsagesCounts};
 use crate::metadata::resolved;
 
-use crate::metadata::resolved::subgraph::{
-    QualifiedBaseType, QualifiedTypeName, QualifiedTypeReference,
-};
+use crate::metadata::resolved::{QualifiedBaseType, QualifiedTypeName, QualifiedTypeReference};
 use crate::schema::types;
 use crate::schema::GDS;
 
@@ -189,7 +187,7 @@ fn make_permission_binary_boolean_expression(
     ndc_column: String,
     argument_type: &QualifiedTypeReference,
     operator: &str,
-    value_expression: &resolved::permission::ValueExpression,
+    value_expression: &resolved::ValueExpression,
     session_variables: &SessionVariables,
     relationship_paths: &Vec<NDCRelationshipName>,
 ) -> Result<ndc_models::Expression, Error> {
@@ -224,13 +222,13 @@ fn make_permission_unary_boolean_expression(
 }
 
 pub(crate) fn make_value_from_value_expression(
-    val_expr: &resolved::permission::ValueExpression,
+    val_expr: &resolved::ValueExpression,
     value_type: &QualifiedTypeReference,
     session_variables: &SessionVariables,
 ) -> Result<serde_json::Value, Error> {
     match val_expr {
-        resolved::permission::ValueExpression::Literal(val) => Ok(val.clone()),
-        resolved::permission::ValueExpression::SessionVariable(session_var) => {
+        resolved::ValueExpression::Literal(val) => Ok(val.clone()),
+        resolved::ValueExpression::SessionVariable(session_var) => {
             let value = session_variables.get(session_var).ok_or_else(|| {
                 InternalDeveloperError::MissingSessionVariable {
                     session_variable: session_var.clone(),
@@ -239,7 +237,7 @@ pub(crate) fn make_value_from_value_expression(
 
             typecast_session_variable(value, value_type)
         }
-        resolved::permission::ValueExpression::BooleanExpression(_model_predicate) => {
+        resolved::ValueExpression::BooleanExpression(_model_predicate) => {
             Err(InternalDeveloperError::BooleanExpressionNotImplemented.into())
         }
     }

v3/crates/engine/src/execute/ir/query_root.rs

@@ -11,8 +11,7 @@ use std::collections::HashMap;
 use super::commands;
 use super::root_field;
 use crate::execute::error;
-use crate::metadata::resolved::subgraph::QualifiedTypeReference;
-use crate::metadata::resolved::{self, subgraph};
+use crate::metadata::resolved;
 use crate::schema::types::ApolloFederationRootFields;
 use crate::schema::types::CommandSourceDetail;
 use crate::schema::types::EntityFieldTypeNameMapping;
@@ -170,12 +169,12 @@ fn generate_type_field_ir<'n, 's>(
 fn generate_model_rootfield_ir<'n, 's>(
     type_name: &ast::TypeName,
     source: &'s Option<resolved::ModelSource>,
-    data_type: &subgraph::Qualified<CustomTypeName>,
+    data_type: &resolved::Qualified<CustomTypeName>,
     kind: &RootFieldKind,
     field: &'n gql::normalized_ast::Field<'s, GDS>,
     field_call: &'s gql::normalized_ast::FieldCall<'s, GDS>,
     session: &Session,
-    model_name: &'s subgraph::Qualified<models::ModelName>,
+    model_name: &'s resolved::Qualified<models::ModelName>,
 ) -> Result<root_field::QueryRootField<'n, 's>, error::Error> {
     let source =
         source
@@ -212,11 +211,11 @@ fn generate_model_rootfield_ir<'n, 's>(
 }
 
 fn generate_command_rootfield_ir<'n, 's>(
-    name: &'s subgraph::Qualified<CommandName>,
+    name: &'s resolved::Qualified<CommandName>,
     type_name: &ast::TypeName,
     function_name: &'s Option<open_dds::commands::FunctionName>,
     source: &'s Option<CommandSourceDetail>,
-    result_type: &'s QualifiedTypeReference,
+    result_type: &'s resolved::QualifiedTypeReference,
     result_base_type_kind: &'s TypeKind,
     field: &'n gql::normalized_ast::Field<'s, GDS>,
     field_call: &'s gql::normalized_ast::FieldCall<'s, GDS>,

v3/crates/engine/src/execute/ir/query_root/apollo_federation.rs

@@ -11,8 +11,8 @@ use crate::execute::ir::filter::ResolvedFilterExpression;
 use crate::execute::ir::model_selection;
 use crate::execute::model_tracking::UsagesCounts;
 use crate::metadata::resolved;
-use crate::metadata::resolved::subgraph::Qualified;
-use crate::metadata::resolved::types::mk_name;
+use crate::metadata::resolved::mk_name;
+use crate::metadata::resolved::Qualified;
 use crate::schema::types::{EntityFieldTypeNameMapping, NamespaceAnnotation};
 use crate::schema::GDS;
 use crate::utils::HashMapWithJsonKey;

v3/crates/engine/src/execute/ir/query_root/node_field.rs

@@ -14,7 +14,7 @@ use crate::execute::ir::filter::ResolvedFilterExpression;
 use crate::execute::ir::model_selection;
 use crate::execute::model_tracking::UsagesCounts;
 use crate::metadata::resolved;
-use crate::metadata::resolved::subgraph::Qualified;
+use crate::metadata::resolved::Qualified;
 use crate::schema::types::{GlobalID, NamespaceAnnotation, NodeFieldTypeNameMapping};
 use crate::schema::GDS;
 use crate::utils::HashMapWithJsonKey;

v3/crates/engine/src/execute/ir/query_root/select_many.rs

@@ -21,7 +21,7 @@ use crate::execute::ir::order_by::build_ndc_order_by;
 use crate::execute::ir::permissions;
 use crate::execute::model_tracking::{count_model, UsagesCounts};
 use crate::metadata::resolved;
-use crate::metadata::resolved::subgraph::Qualified;
+use crate::metadata::resolved::Qualified;
 use crate::schema::types::{self, Annotation, BooleanExpressionAnnotation, ModelInputAnnotation};
 use crate::schema::GDS;
 

v3/crates/engine/src/execute/ir/query_root/select_one.rs

@@ -19,7 +19,7 @@ use crate::execute::ir::model_selection;
 use crate::execute::ir::permissions;
 use crate::execute::model_tracking::{count_model, UsagesCounts};
 use crate::metadata::resolved;
-use crate::metadata::resolved::subgraph::Qualified;
+use crate::metadata::resolved::Qualified;
 
 use crate::schema::types::{self, Annotation, ModelInputAnnotation};
 use crate::schema::GDS;

v3/crates/engine/src/execute/ir/relationship.rs

@@ -23,7 +23,7 @@ use super::{
 };
 
 use crate::execute::model_tracking::{count_model, UsagesCounts};
-use crate::metadata::resolved::subgraph::serialize_qualified_btreemap;
+use crate::metadata::resolved::{serialize_qualified_btreemap, Qualified};
 use crate::schema::types::output_type::relationship::{
     ModelRelationshipAnnotation, ModelTargetSource,
 };
@@ -34,7 +34,7 @@ use crate::{
     },
 };
 use crate::{
-    metadata::resolved::{self, subgraph::Qualified},
+    metadata::resolved,
     schema::{
         types::{Annotation, BooleanExpressionAnnotation, InputAnnotation, ModelInputAnnotation},
         GDS,
@@ -46,7 +46,7 @@ pub(crate) struct LocalModelRelationshipInfo<'s> {
     pub relationship_name: &'s RelationshipName,
     pub relationship_type: &'s RelationshipType,
     pub source_type: &'s Qualified<CustomTypeName>,
-    pub source_data_connector: &'s resolved::stages::data_connectors::DataConnectorLink,
+    pub source_data_connector: &'s resolved::DataConnectorLink,
     #[serde(serialize_with = "serialize_qualified_btreemap")]
     pub source_type_mappings: &'s BTreeMap<Qualified<CustomTypeName>, resolved::TypeMapping>,
     pub target_source: &'s ModelTargetSource,
@@ -57,7 +57,7 @@ pub(crate) struct LocalModelRelationshipInfo<'s> {
 #[derive(Debug, Serialize)]
 pub(crate) struct LocalCommandRelationshipInfo<'s> {
     pub annotation: &'s CommandRelationshipAnnotation,
-    pub source_data_connector: &'s resolved::stages::data_connectors::DataConnectorLink,
+    pub source_data_connector: &'s resolved::DataConnectorLink,
     #[serde(serialize_with = "serialize_qualified_btreemap")]
     pub source_type_mappings: &'s BTreeMap<Qualified<CustomTypeName>, resolved::TypeMapping>,
     pub target_source: &'s CommandTargetSource,
@@ -80,7 +80,7 @@ pub(crate) struct RemoteCommandRelationshipInfo<'s> {
 }
 
 pub type SourceField = (FieldName, resolved::FieldMapping);
-pub type TargetField = (FieldName, resolved::types::NdcColumnForComparison);
+pub type TargetField = (FieldName, resolved::NdcColumnForComparison);
 
 pub(crate) fn process_model_relationship_definition(
     relationship_info: &LocalModelRelationshipInfo,
@@ -212,7 +212,7 @@ pub(crate) fn process_command_relationship_definition(
 pub(crate) fn generate_model_relationship_ir<'s>(
     field: &Field<'s, GDS>,
     annotation: &'s ModelRelationshipAnnotation,
-    source_data_connector: &'s resolved::stages::data_connectors::DataConnectorLink,
+    source_data_connector: &'s resolved::DataConnectorLink,
     type_mappings: &'s BTreeMap<Qualified<CustomTypeName>, resolved::TypeMapping>,
     session_variables: &SessionVariables,
     usage_counts: &mut UsagesCounts,
@@ -328,7 +328,7 @@ pub(crate) fn generate_model_relationship_ir<'s>(
 pub(crate) fn generate_command_relationship_ir<'s>(
     field: &Field<'s, GDS>,
     annotation: &'s CommandRelationshipAnnotation,
-    source_data_connector: &'s resolved::stages::data_connectors::DataConnectorLink,
+    source_data_connector: &'s resolved::DataConnectorLink,
     type_mappings: &'s BTreeMap<Qualified<CustomTypeName>, resolved::TypeMapping>,
     session_variables: &SessionVariables,
     usage_counts: &mut UsagesCounts,
@@ -382,7 +382,7 @@ pub(crate) fn build_local_model_relationship<'s>(
     field: &normalized_ast::Field<'s, GDS>,
     field_call: &normalized_ast::FieldCall<'s, GDS>,
     annotation: &'s ModelRelationshipAnnotation,
-    data_connector: &'s resolved::stages::data_connectors::DataConnectorLink,
+    data_connector: &'s resolved::DataConnectorLink,
     type_mappings: &'s BTreeMap<Qualified<CustomTypeName>, resolved::TypeMapping>,
     target_source: &'s ModelTargetSource,
     filter_clause: ResolvedFilterExpression<'s>,
@@ -428,7 +428,7 @@ pub(crate) fn build_local_command_relationship<'s>(
     field: &normalized_ast::Field<'s, GDS>,
     field_call: &normalized_ast::FieldCall<'s, GDS>,
     annotation: &'s CommandRelationshipAnnotation,
-    data_connector: &'s resolved::stages::data_connectors::DataConnectorLink,
+    data_connector: &'s resolved::DataConnectorLink,
     type_mappings: &'s BTreeMap<Qualified<CustomTypeName>, resolved::TypeMapping>,
     target_source: &'s CommandTargetSource,
     session_variables: &SessionVariables,

v3/crates/engine/src/execute/ir/selection_set.rs

@@ -19,9 +19,6 @@ use crate::execute::error::{self};
 use crate::execute::global_id;
 use crate::execute::model_tracking::UsagesCounts;
 use crate::metadata::resolved;
-use crate::metadata::resolved::subgraph::{
-    Qualified, QualifiedBaseType, QualifiedTypeName, QualifiedTypeReference,
-};
 use crate::schema::types::TypeKind;
 use crate::schema::{
     types::{Annotation, OutputAnnotation, RootFieldAnnotation},
@@ -87,7 +84,7 @@ pub struct NDCRelationshipName(pub(crate) String);
 
 impl NDCRelationshipName {
     pub fn new(
-        source_type: &Qualified<CustomTypeName>,
+        source_type: &resolved::Qualified<CustomTypeName>,
         relationship_name: &RelationshipName,
     ) -> Result<Self, error::Error> {
         let name = serde_json::to_string(&(source_type, relationship_name))?;
@@ -151,16 +148,16 @@ fn build_global_id_fields(
 }
 
 pub(crate) fn generate_nested_selection<'s>(
-    qualified_type_reference: &QualifiedTypeReference,
+    qualified_type_reference: &resolved::QualifiedTypeReference,
     field_base_type_kind: TypeKind,
     field: &normalized_ast::Field<'s, GDS>,
-    data_connector: &'s resolved::stages::data_connectors::DataConnectorLink,
-    type_mappings: &'s BTreeMap<Qualified<CustomTypeName>, resolved::TypeMapping>,
+    data_connector: &'s resolved::DataConnectorLink,
+    type_mappings: &'s BTreeMap<resolved::Qualified<CustomTypeName>, resolved::TypeMapping>,
     session_variables: &SessionVariables,
     usage_counts: &mut UsagesCounts,
 ) -> Result<Option<NestedSelection<'s>>, error::Error> {
     match &qualified_type_reference.underlying_type {
-        QualifiedBaseType::List(element_type) => {
+        resolved::QualifiedBaseType::List(element_type) => {
             let array_selection = generate_nested_selection(
                 element_type,
                 field_base_type_kind,
@@ -172,10 +169,10 @@ pub(crate) fn generate_nested_selection<'s>(
             )?;
             Ok(array_selection.map(|a| NestedSelection::Array(Box::new(a))))
         }
-        QualifiedBaseType::Named(qualified_type_name) => {
+        resolved::QualifiedBaseType::Named(qualified_type_name) => {
             match qualified_type_name {
-                QualifiedTypeName::Inbuilt(_) => Ok(None), // Inbuilt types are all scalars so there should be no subselections.
-                QualifiedTypeName::Custom(data_type) => match field_base_type_kind {
+                resolved::QualifiedTypeName::Inbuilt(_) => Ok(None), // Inbuilt types are all scalars so there should be no subselections.
+                resolved::QualifiedTypeName::Custom(data_type) => match field_base_type_kind {
                     TypeKind::Scalar => Ok(None),
                     TypeKind::Object => {
                         let resolved::TypeMapping::Object { field_mappings, .. } = type_mappings
@@ -205,8 +202,8 @@ pub(crate) fn generate_nested_selection<'s>(
 /// sources depending on the model being queried.
 pub(crate) fn generate_selection_set_ir<'s>(
     selection_set: &normalized_ast::SelectionSet<'s, GDS>,
-    data_connector: &'s resolved::stages::data_connectors::DataConnectorLink,
-    type_mappings: &'s BTreeMap<Qualified<CustomTypeName>, resolved::TypeMapping>,
+    data_connector: &'s resolved::DataConnectorLink,
+    type_mappings: &'s BTreeMap<resolved::Qualified<CustomTypeName>, resolved::TypeMapping>,
     field_mappings: &BTreeMap<FieldName, resolved::FieldMapping>,
     session_variables: &SessionVariables,
     usage_counts: &mut UsagesCounts,