feat: draft partial index support

libs/sql-ddl/src/postgres.rs

@@ -347,6 +347,7 @@ pub struct CreateIndex<'a> {
     pub table_reference: &'a dyn Display,
     pub columns: Vec<IndexColumn<'a>>,
     pub using: Option<IndexAlgorithm>,
+    pub where_clause: Option<&'a str>,
 }
 
 impl Display for CreateIndex<'_> {
@@ -388,7 +389,13 @@ impl Display for CreateIndex<'_> {
             })
             .join(", ", f)?;
 
-        f.write_str(")")
+        f.write_str(")")?;
+
+        if let Some(where_clause) = self.where_clause {
+            write!(f, " WHERE {where_clause}")?;
+        }
+
+        Ok(())
     }
 }
 
@@ -432,6 +439,7 @@ mod tests {
             table_reference: &PostgresIdentifier::Simple(Cow::Borrowed("Cat")),
             columns,
             using: None,
+            where_clause: None,
         };
 
         assert_eq!(
@@ -450,6 +458,7 @@ mod tests {
             table_reference: &PostgresIdentifier::Simple(Cow::Borrowed("Cat")),
             columns,
             using: Some(IndexAlgorithm::Hash),
+            where_clause: None,
         };
 
         assert_eq!(
@@ -479,6 +488,7 @@ mod tests {
             table_reference: &PostgresIdentifier::Simple("Cat".into()),
             columns,
             using: None,
+            where_clause: None,
         };
 
         assert_eq!(

psl/parser-database/src/attributes.rs

@@ -537,6 +537,20 @@ fn model_index(data: &mut ModelAttributes, model_id: crate::ModelId, ctx: &mut C
     index_attribute.algorithm = algo;
     index_attribute.clustered = validate_clustering_setting(ctx);
 
+    let where_clause = match ctx
+        .visit_optional_arg("where")
+        .and_then(|expr| coerce::string(expr, ctx.diagnostics))
+    {
+        Some("") => {
+            ctx.push_attribute_validation_error("The `where` argument cannot be an empty string.");
+            None
+        }
+        Some(clause) => Some(ctx.interner.intern(clause)),
+        None => None,
+    };
+
+    index_attribute.where_clause = where_clause;
+
     data.ast_indexes.push((ctx.current_attribute_id().1, index_attribute));
 }
 
@@ -593,6 +607,20 @@ fn model_unique(data: &mut ModelAttributes, model_id: crate::ModelId, ctx: &mut
     index_attribute.mapped_name = mapped_name;
     index_attribute.clustered = validate_clustering_setting(ctx);
 
+    let where_clause = match ctx
+        .visit_optional_arg("where")
+        .and_then(|expr| coerce::string(expr, ctx.diagnostics))
+    {
+        Some("") => {
+            ctx.push_attribute_validation_error("The `where` argument cannot be an empty string.");
+            None
+        }
+        Some(clause) => Some(ctx.interner.intern(clause)),
+        None => None,
+    };
+
+    index_attribute.where_clause = where_clause;
+
     data.ast_indexes.push((current_attribute_id.1, index_attribute));
 }
 

psl/parser-database/src/types.rs

@@ -493,6 +493,7 @@ pub(crate) struct IndexAttribute {
     pub(crate) mapped_name: Option<StringId>,
     pub(crate) algorithm: Option<IndexAlgorithm>,
     pub(crate) clustered: Option<bool>,
+    pub(crate) where_clause: Option<StringId>,
 }
 
 impl IndexAttribute {

psl/parser-database/src/walkers/index.rs

@@ -177,6 +177,11 @@ impl<'db> IndexWalker<'db> {
         self.index_attribute.clustered
     }
 
+    /// The WHERE clause of the partial index, if any.
+    pub fn where_clause(self) -> Option<&'db str> {
+        self.index_attribute.where_clause.map(|id| &self.db[id])
+    }
+
     /// The model the index is defined on.
     pub fn model(self) -> ModelWalker<'db> {
         self.db.walk(self.model_id)

psl/psl-core/src/common/preview_features.rs

@@ -73,6 +73,7 @@ features!(
     OrderByAggregateGroup,
     OrderByNulls,
     OrderByRelation,
+    PartialIndexes,
     PostgresqlExtensions,
     PrismaSchemaFolder,
     QueryCompiler,
@@ -156,6 +157,7 @@ impl<'a> FeatureMapWithProvider<'a> {
                  DriverAdapters
                  | Metrics
                  | NativeDistinct
+                 | PartialIndexes
                  | PostgresqlExtensions
                  | QueryCompiler
                  | RelationJoins

psl/psl-core/src/validate/validation_pipeline/validations.rs

@@ -138,6 +138,7 @@ pub(super) fn validate(ctx: &mut Context<'_>) {
             indexes::clustering_can_be_defined_only_once(index, ctx);
             indexes::opclasses_are_not_allowed_with_other_than_normal_indices(index, ctx);
             indexes::composite_type_in_compound_unique_index(index, ctx);
+            indexes::partial_index_is_supported(index, ctx);
 
             for field_attribute in index.scalar_field_attributes() {
                 let span = index.ast_attribute().span;

psl/psl-core/src/validate/validation_pipeline/validations/indexes.rs

@@ -1,5 +1,6 @@
 use super::{constraint_namespace::ConstraintName, database_name::validate_db_name};
 use crate::{
+    PreviewFeature,
     datamodel_connector::{ConnectorCapability, walker_ext_traits::*},
     diagnostics::DatamodelError,
     validate::validation_pipeline::context::Context,
@@ -398,3 +399,35 @@ pub(super) fn unique_client_name_does_not_clash_with_field(index: IndexWalker<'_
         ));
     }
 }
+
+/// Partial indexes are only supported on PostgreSQL and CockroachDB with the partialIndexes preview feature.
+pub(crate) fn partial_index_is_supported(index: IndexWalker<'_>, ctx: &mut Context<'_>) {
+    if index.where_clause().is_none() {
+        return;
+    }
+
+    if !ctx.preview_features.contains(PreviewFeature::PartialIndexes) {
+        let message = "You have a partial index definition. Partial indexes are currently a preview feature. To use partial indexes, please add \"partialIndexes\" to the preview features.";
+
+        ctx.push_error(DatamodelError::new_attribute_validation_error(
+            message,
+            index.attribute_name(),
+            index.ast_attribute().span,
+        ));
+
+        return;
+    }
+
+    let connector_name = ctx.connector.provider_name();
+    if !matches!(connector_name, "postgresql" | "cockroachdb") {
+        let message = format!(
+            "Partial indexes are only supported on PostgreSQL and CockroachDB. Your connector is `{connector_name}`."
+        );
+
+        ctx.push_error(DatamodelError::new_attribute_validation_error(
+            &message,
+            index.attribute_name(),
+            index.ast_attribute().span,
+        ));
+    }
+}

psl/psl/tests/config/generators.rs

@@ -256,7 +256,7 @@ fn nice_error_for_unknown_generator_preview_feature() {
         .unwrap_err();
 
     let expectation = expect![[r#"
-        error: The preview feature "foo" is not known. Expected one of: driverAdapters, metrics, nativeDistinct, postgresqlExtensions, queryCompiler, relationJoins, shardKeys, strictUndefinedChecks, views
+        error: The preview feature "foo" is not known. Expected one of: driverAdapters, metrics, nativeDistinct, partialIndexes, postgresqlExtensions, queryCompiler, relationJoins, shardKeys, strictUndefinedChecks, views
           -->  schema.prisma:3
            | 
          2 |   provider = "prisma-client-js"

psl/psl/tests/validation/preview_features/native_full_text_search_postgres/mysql.prisma

@@ -14,7 +14,7 @@ model Blog {
   title   String
   @@fulltext([content, title])
 }
-// error: The preview feature "fullTextSearchPostgres" is not known. Expected one of: driverAdapters, metrics, nativeDistinct, postgresqlExtensions, queryCompiler, relationJoins, shardKeys, strictUndefinedChecks, views
+// error: The preview feature "fullTextSearchPostgres" is not known. Expected one of: driverAdapters, metrics, nativeDistinct, partialIndexes, postgresqlExtensions, queryCompiler, relationJoins, shardKeys, strictUndefinedChecks, views
 //   -->  schema.prisma:3
 //    | 
 //  2 |   provider        = "prisma-client-js"

psl/psl/tests/validation/preview_features/partial_indexes/cockroachdb_basic.prisma

@@ -0,0 +1,20 @@
+generator client {
+  provider        = "prisma-client-js"
+  previewFeatures = ["partialIndexes"]
+}
+
+datasource db {
+  provider = "cockroachdb"
+  url      = env("DATABASE_URL")
+}
+
+model Post {
+  id        Int      @id
+  title     String
+  content   String?
+  published Boolean  @default(false)
+  authorId  Int
+
+  @@index([title], where: "published = true")
+  @@unique([authorId, title], where: "published = true")
+}

psl/psl/tests/validation/preview_features/partial_indexes/empty_where_clause.prisma

@@ -0,0 +1,23 @@
+generator client {
+  provider        = "prisma-client-js"
+  previewFeatures = ["partialIndexes"]
+}
+
+datasource db {
+  provider = "postgresql"
+  url      = env("DATABASE_URL")
+}
+
+model User {
+  id       Int     @id
+  email    String  @unique
+  isActive Boolean @default(true)
+
+  @@index([email], where: "")
+}
+// error: Error parsing attribute "@index": The `where` argument cannot be an empty string.
+//   -->  schema.prisma:16
+//    | 
+// 15 | 
+// 16 |   @@index([email], where: "")
+//    | 

psl/psl/tests/validation/preview_features/partial_indexes/empty_where_clause_unique.prisma

@@ -0,0 +1,23 @@
+generator client {
+  provider        = "prisma-client-js"
+  previewFeatures = ["partialIndexes"]
+}
+
+datasource db {
+  provider = "postgresql"
+  url      = env("DATABASE_URL")
+}
+
+model User {
+  id       Int     @id
+  email    String  @unique
+  isActive Boolean @default(true)
+
+  @@unique([email], where: "")
+}
+// error: Error parsing attribute "@unique": The `where` argument cannot be an empty string.
+//   -->  schema.prisma:16
+//    | 
+// 15 | 
+// 16 |   @@unique([email], where: "")
+//    | 

psl/psl/tests/validation/preview_features/partial_indexes/mysql_unsupported.prisma

@@ -0,0 +1,23 @@
+generator client {
+  provider        = "prisma-client-js"
+  previewFeatures = ["partialIndexes"]
+}
+
+datasource db {
+  provider = "mysql"
+  url      = env("DATABASE_URL")
+}
+
+model User {
+  id       Int     @id
+  email    String  @unique
+  isActive Boolean @default(true)
+
+  @@index([email], where: "isActive = true")
+}
+// error: Error parsing attribute "@@index": Partial indexes are only supported on PostgreSQL and CockroachDB. Your connector is `mysql`.
+//   -->  schema.prisma:16
+//    | 
+// 15 | 
+// 16 |   @@index([email], where: "isActive = true")
+//    | 

psl/psl/tests/validation/preview_features/partial_indexes/no_preview_feature.prisma

@@ -0,0 +1,22 @@
+generator client {
+  provider = "prisma-client-js"
+}
+
+datasource db {
+  provider = "postgresql"
+  url      = env("DATABASE_URL")
+}
+
+model User {
+  id       Int     @id
+  email    String  @unique
+  isActive Boolean @default(true)
+
+  @@index([email], where: "isActive = true")
+}
+// error: Error parsing attribute "@@index": You have a partial index definition. Partial indexes are currently a preview feature. To use partial indexes, please add "partialIndexes" to the preview features.
+//   -->  schema.prisma:15
+//    | 
+// 14 | 
+// 15 |   @@index([email], where: "isActive = true")
+//    | 

psl/psl/tests/validation/preview_features/partial_indexes/postgresql_basic.prisma

@@ -0,0 +1,19 @@
+generator client {
+  provider        = "prisma-client-js"
+  previewFeatures = ["partialIndexes"]
+}
+
+datasource db {
+  provider = "postgresql"
+  url      = env("DATABASE_URL")
+}
+
+model User {
+  id       Int     @id
+  email    String  @unique
+  name     String?
+  isActive Boolean @default(true)
+
+  @@index([email], where: "isActive = true")
+  @@unique([name], where: "name IS NOT NULL")
+}

psl/psl/tests/validation/preview_features/partial_indexes/sqlite_unsupported.prisma

@@ -0,0 +1,23 @@
+generator client {
+  provider        = "prisma-client-js"
+  previewFeatures = ["partialIndexes"]
+}
+
+datasource db {
+  provider = "sqlite"
+  url      = env("DATABASE_URL")
+}
+
+model User {
+  id       Int     @id
+  email    String  @unique
+  isActive Boolean @default(true)
+
+  @@index([email], where: "isActive = true")
+}
+// error: Error parsing attribute "@@index": Partial indexes are only supported on PostgreSQL and CockroachDB. Your connector is `sqlite`.
+//   -->  schema.prisma:16
+//    | 
+// 15 | 
+// 16 |   @@index([email], where: "isActive = true")
+//    | 

schema-engine/connectors/sql-schema-connector/src/flavour/postgres/renderer.rs

@@ -391,6 +391,7 @@ impl SqlRenderer for PostgresRenderer {
                     operator_class: pg_ext.get_opclass(c.id).map(|c| c.kind.as_ref().into()),
                 })
                 .collect(),
+            where_clause: pg_ext.get_partial_index_where_clause(index.id).map(|s| s.as_str()),
         }
         .to_string()
     }

schema-engine/connectors/sql-schema-connector/src/flavour/postgres/schema_calculator.rs

@@ -137,6 +137,13 @@ impl SqlSchemaCalculatorFlavour for PostgresSchemaCalculatorFlavour {
                         postgres_ext.opclasses.push((field_id, opclass));
                     }
                 }
+
+                // Add WHERE clause for partial indexes
+                if let Some(where_clause) = index.where_clause() {
+                    postgres_ext
+                        .partial_indexes
+                        .insert(sql_index.id, where_clause.to_string());
+                }
             }
 
             // Add sequences for the fields with a default sequence in the model.