internal/config: support golang overrides for slices (#2339)

* internal/config: support an additional boolean field named "slice" on the "go_type" override property, and update docs

* revert unrelated import string prefix change, and add pgx tests

Author: andrewmbenton

docs/reference/config.md

@@ -189,17 +189,33 @@ Each mapping of the `overrides` collection has the following keys:
 
 - `db_type`:
   - The PostgreSQL or MySQL type to override. Find the full list of supported types in [postgresql_type.go](https://github.com/kyleconroy/sqlc/blob/main/internal/codegen/golang/postgresql_type.go#L12) or [mysql_type.go](https://github.com/kyleconroy/sqlc/blob/main/internal/codegen/golang/mysql_type.go#L12). Note that for Postgres you must use the pg_catalog prefixed names where available. Can't be used if the `column` key is defined.
-- `column`
+- `column`:
   - In case the type overriding should be done on specific a column of a table instead of a type. `column` should be of the form `table.column` but you can be even more specific by specifying `schema.table.column` or `catalog.schema.table.column`. Can't be used if the `db_type` key is defined.
 - `go_type`:
   - A fully qualified name to a Go type to use in the generated code.
 - `go_struct_tag`:
   - A reflect-style struct tag to use in the generated code, e.g. `a:"b" x:"y,z"`.
     If you want general json/db tags for all fields, use `emit_db_tags` and/or `emit_json_tags` instead.
 - `nullable`:
-  - If true, use this type when a column is nullable. Defaults to `false`.
+  - If `true`, use this type when a column is nullable. Defaults to `false`.
 
-For more complicated import paths, the `go_type` can also be an object.
+When generating code, entries using the `column` key will always have preference over
+entries using the `db_type` key in order to generate the struct.
+
+For more complicated import paths, the `go_type` can also be an object with the following keys:
+
+- `import`:
+  - The import path for the package where the type is defined.
+- `package`:
+  - The package name where the type is defined. This should only be necessary when your import path doesn't end with the desired package name.
+- `type`:
+  - The type name itself, without any package prefix.
+- `pointer`:
+  - If set to `true`, generated code will use pointers to the type rather than the type itself.
+- `slice`:
+  - If set to `true`, generated code will use a slice of the type rather than the type itself.
+
+An example:
 
 ```yaml
 version: "2"
@@ -220,9 +236,6 @@ sql:
             pointer: true
 ```
 
-When generating code, entries using the `column` key will always have preference over
-entries using the `db_type` key in order to generate the struct.
-
 #### kotlin
 
 > Removed in v1.17.0 and replaced by the [sqlc-gen-kotlin](https://github.com/tabbed/sqlc-gen-kotlin) plugin. Follow the [migration guide](../guides/migrating-to-sqlc-gen-kotlin) to switch.

internal/cmd/shim.go

@@ -114,7 +114,7 @@ func pluginGoType(o config.Override) *plugin.ParsedGoType {
 	// Note that there is a slight mismatch between this and the
 	// proto api. The GoType on the override is the unparsed type,
 	// which could be a qualified path or an object, as per
-	// https://docs.sqlc.dev/en/latest/reference/config.html#renaming-struct-fields
+	// https://docs.sqlc.dev/en/v1.18.0/reference/config.html#type-overriding
 	return &plugin.ParsedGoType{
 		ImportPath: o.GoImportPath,
 		Package:    o.GoPackage,

internal/codegen/golang/imports.go

@@ -257,9 +257,7 @@ func (i *importer) interfaceImports() fileImports {
 }
 
 func (i *importer) modelImports() fileImports {
-	std, pkg := buildImports(i.Settings, nil, func(prefix string) bool {
-		return i.usesType(prefix)
-	})
+	std, pkg := buildImports(i.Settings, nil, i.usesType)
 
 	if len(i.Enums) > 0 {
 		std["fmt"] = struct{}{}

internal/config/go_type.go

@@ -13,6 +13,7 @@ type GoType struct {
 	Package string `json:"package" yaml:"package"`
 	Name    string `json:"type" yaml:"type"`
 	Pointer bool   `json:"pointer" yaml:"pointer"`
+	Slice   bool   `json:"slice" yaml:"slice"`
 	Spec    string
 	BuiltIn bool
 }
@@ -104,6 +105,9 @@ func (gt GoType) Parse() (*ParsedGoType, error) {
 		if gt.Pointer {
 			o.TypeName = "*" + o.TypeName
 		}
+		if gt.Slice {
+			o.TypeName = "[]" + o.TypeName
+		}
 		return &o, nil
 	}
 

internal/endtoend/testdata/overrides_array/postgresql/pgx/v4/query.sql

@@ -0,0 +1,11 @@
+-- Example queries for sqlc
+CREATE TABLE authors (
+  id   BIGSERIAL PRIMARY KEY,
+  name text      NOT NULL,
+  bio  text,
+  tags string[]
+);
+
+-- name: GetAuthor :one
+SELECT * FROM authors
+WHERE id = $1 LIMIT 1;

internal/endtoend/testdata/overrides_array/postgresql/pgx/v4/query/db.go

@@ -0,0 +1,23 @@
+{
+    "version": "2",
+    "sql": [{
+        "schema": "query.sql",
+        "queries": "query.sql",
+        "engine": "postgresql",
+        "gen": {
+            "go": {
+                "sql_package": "pgx/v4",
+                "package": "query",
+                "out": "query",
+                "overrides": [{
+                    "column": "authors.tags",
+                    "go_type": {
+                      "type": "NullInt64",
+                      "import": "database/sql",
+                      "slice": true
+                    }
+                }]
+            }
+        }
+    }]
+}

internal/endtoend/testdata/overrides_array/postgresql/pgx/v4/query/models.go

@@ -0,0 +1,11 @@
+-- Example queries for sqlc
+CREATE TABLE authors (
+  id   BIGSERIAL PRIMARY KEY,
+  name text      NOT NULL,
+  bio  text,
+  tags string[]
+);
+
+-- name: GetAuthor :one
+SELECT * FROM authors
+WHERE id = $1 LIMIT 1;