Feature filter unused structs in models

docs/reference/config.md

@@ -111,6 +111,8 @@ The `gen` mapping supports the following keys:
 - `emit_all_enum_values`:
   - If true, emit a function per enum type
     that returns all valid enum values.
+- `emit_filter_unused_models`:
+  - If true, emit a filter unused models for `models.go` file.
 - `json_tags_case_style`:
   - `camel` for camelCase, `pascal` for PascalCase, `snake` for snake_case or `none` to use the column name in the DB. Defaults to `none`.
 - `output_batch_file_name`:

internal/cmd/shim.go

@@ -83,6 +83,7 @@ func pluginGoCode(s config.SQLGo) *plugin.GoCode {
 
 	return &plugin.GoCode{
 		EmitInterface:               s.EmitInterface,
+		EmitFilterUnusedModels:      s.EmitFilterUnusedModels,
 		EmitJsonTags:                s.EmitJSONTags,
 		EmitDbTags:                  s.EmitDBTags,
 		EmitPreparedQueries:         s.EmitPreparedQueries,

internal/codegen/golang/gen.go

@@ -107,6 +107,9 @@ func Generate(ctx context.Context, req *plugin.CodeGenRequest) (*plugin.CodeGenR
 	if err != nil {
 		return nil, err
 	}
+	if req.Settings.Go.EmitFilterUnusedModels {
+		enums, structs = removeUnused(enums, structs, queries)
+	}
 	return generate(req, enums, structs, queries)
 }
 

internal/codegen/golang/result.go

@@ -430,3 +430,65 @@ func checkIncompatibleFieldTypes(fields []Field) error {
 	}
 	return nil
 }
+func findStructByName(structs []Struct, structName string) (Struct, bool) {
+	for _, s := range structs {
+		if s.Name == structName {
+			return s, true
+		}
+	}
+	return Struct{}, false
+}
+func findEnumByName(enums []Enum, enumName string) (Enum, bool) {
+	for _, e := range enums {
+		if e.Name == enumName {
+			return e, true
+		}
+	}
+	return Enum{}, false
+}
+
+func removeUnused(enums []Enum, structs []Struct, queries []Query) ([]Enum, []Struct) {
+	filteredStructs := make(map[string]Struct, len(structs))
+	for _, query := range queries {
+		if query.hasRetType() && query.Ret.IsStruct() {
+			structName := query.Ret.Struct.Name
+			_, ok := filteredStructs[structName]
+			if !ok {
+				s, ok := findStructByName(structs, structName)
+				if ok {
+					filteredStructs[structName] = s
+				}
+			}
+		}
+		if query.Arg.IsStruct() {
+			structName := query.Arg.Struct.Name
+			_, ok := filteredStructs[structName]
+			if !ok {
+				s, ok := findStructByName(structs, structName)
+				if ok {
+					filteredStructs[structName] = s
+				}
+			}
+		}
+	}
+	filteredStructsSlice := make([]Struct, 0, len(filteredStructs))
+	filteredEnums := make(map[string]Enum, len(enums))
+	for _, s := range filteredStructs {
+		for _, field := range s.Fields {
+			if _, ok := filteredEnums[field.Type]; ok {
+				continue
+			}
+			enum, ok := findEnumByName(enums, field.Type)
+			if !ok {
+				continue
+			}
+			filteredEnums[field.Type] = enum
+		}
+		filteredStructsSlice = append(filteredStructsSlice, s)
+	}
+	filteredEnumsSlice := make([]Enum, 0, len(filteredEnums))
+	for _, enum := range filteredEnums {
+		filteredEnumsSlice = append(filteredEnumsSlice, enum)
+	}
+	return filteredEnumsSlice, filteredStructsSlice
+}

internal/codegen/golang/result_test.go

@@ -1,6 +1,7 @@
 package golang
 
 import (
+	"reflect"
 	"testing"
 
 	"github.com/kyleconroy/sqlc/internal/metadata"
@@ -76,3 +77,136 @@ func TestPutOutColumns_AlwaysTrueWhenQueryHasColumns(t *testing.T) {
 		t.Error("should be true when we have columns")
 	}
 }
+
+func Test_removeUnused(t *testing.T) {
+	type args struct {
+		enums   []Enum
+		structs []Struct
+		queries []Query
+	}
+	tests := []struct {
+		name  string
+		args  args
+		want  map[string]Enum
+		want1 map[string]Struct
+	}{
+		{
+			name: "remove unused structs and enums",
+			args: args{
+				enums: []Enum{
+					{
+						Name: "enum1",
+					},
+					{
+						Name: "enum2",
+					},
+				},
+				structs: []Struct{
+					{
+						Name: "struct1",
+					},
+					{
+						Name: "struct2",
+					},
+					{
+						Name: "struct3",
+					},
+					{
+						Name: "struct4",
+						Fields: []Field{
+							{
+								Type: "enum1",
+							},
+							{
+								Type: "notenum",
+							},
+						},
+					},
+					{
+						Name: "struct5",
+					},
+				},
+				queries: []Query{
+					{
+						Cmd: metadata.CmdOne,
+						Ret: QueryValue{
+							Struct: &Struct{
+								Name: "struct1",
+							},
+						},
+						Arg: QueryValue{
+							Struct: &Struct{
+								Name: "struct2",
+							},
+						},
+					},
+					{
+						Cmd: metadata.CmdOne,
+						Ret: QueryValue{
+							Struct: &Struct{
+								Name: "struct3",
+							},
+						},
+						Arg: QueryValue{
+							Struct: &Struct{
+								Name: "struct4",
+								Fields: []Field{
+									{
+										Type: "enum1",
+									},
+									{
+										Type: "notenum",
+									},
+								},
+							},
+						},
+					},
+				},
+			},
+			want: map[string]Enum{
+				"enum1": {Name: "enum1"},
+			},
+			want1: map[string]Struct{
+				"struct1": {
+					Name: "struct1",
+				},
+				"struct2": {
+					Name: "struct2",
+				},
+				"struct3": {
+					Name: "struct3",
+				},
+				"struct4": {
+					Name: "struct4",
+					Fields: []Field{
+						{
+							Type: "enum1",
+						},
+						{
+							Type: "notenum",
+						},
+					},
+				},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, got1 := removeUnused(tt.args.enums, tt.args.structs, tt.args.queries)
+			gotMap := map[string]Enum{}
+			got1Map := map[string]Struct{}
+			for _, enum := range got {
+				gotMap[enum.Name] = enum
+			}
+			for _, s := range got1 {
+				got1Map[s.Name] = s
+			}
+			if !reflect.DeepEqual(gotMap, tt.want) {
+				t.Errorf("removeUnused() got = %v, want %v", got, tt.want)
+			}
+			if !reflect.DeepEqual(got1Map, tt.want1) {
+				t.Errorf("removeUnused() got1 = %v, want %v", got1, tt.want1)
+			}
+		})
+	}
+}

internal/config/config.go

@@ -118,6 +118,7 @@ type SQLGen struct {
 
 type SQLGo struct {
 	EmitInterface               bool              `json:"emit_interface" yaml:"emit_interface"`
+	EmitFilterUnusedModels      bool              `json:"emit_filter_unused_models" yaml:"emit_filter_unused_models"`
 	EmitJSONTags                bool              `json:"emit_json_tags" yaml:"emit_json_tags"`
 	EmitDBTags                  bool              `json:"emit_db_tags" yaml:"emit_db_tags"`
 	EmitPreparedQueries         bool              `json:"emit_prepared_queries" yaml:"emit_prepared_queries"`

internal/config/v_one.go

@@ -24,6 +24,7 @@ type v1PackageSettings struct {
 	Schema                    Paths      `json:"schema" yaml:"schema"`
 	Queries                   Paths      `json:"queries" yaml:"queries"`
 	EmitInterface             bool       `json:"emit_interface" yaml:"emit_interface"`
+	EmitFilterUnusedModels    bool       `json:"emit_filter_unused_models" yaml:"emit_filter_unused_models"`
 	EmitJSONTags              bool       `json:"emit_json_tags" yaml:"emit_json_tags"`
 	EmitDBTags                bool       `json:"emit_db_tags" yaml:"emit_db_tags"`
 	EmitPreparedQueries       bool       `json:"emit_prepared_queries" yaml:"emit_prepared_queries"`
@@ -142,6 +143,7 @@ func (c *V1GenerateSettings) Translate() Config {
 			Gen: SQLGen{
 				Go: &SQLGo{
 					EmitInterface:             pkg.EmitInterface,
+					EmitFilterUnusedModels:    pkg.EmitFilterUnusedModels,
 					EmitJSONTags:              pkg.EmitJSONTags,
 					EmitDBTags:                pkg.EmitDBTags,
 					EmitPreparedQueries:       pkg.EmitPreparedQueries,

internal/endtoend/testdata/codegen_json/gen/codegen.json

@@ -40,7 +40,8 @@
       "inflection_exclude_table_names": [],
       "emit_pointers_for_null_types": false,
       "query_parameter_limit": 1,
-      "output_batch_file_name": ""
+      "output_batch_file_name": "",
+      "emit_filter_unused_models": false
     },
     "json": {
       "out": "gen",