fix: handle empty column list in postgresql (#1843)

Author: akutschera

internal/codegen/golang/result.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/kyleconroy/sqlc/internal/codegen/sdk"
 	"github.com/kyleconroy/sqlc/internal/inflection"
+	"github.com/kyleconroy/sqlc/internal/metadata"
 	"github.com/kyleconroy/sqlc/internal/plugin"
 )
 
@@ -200,7 +201,7 @@ func buildQueries(req *plugin.CodeGenRequest, structs []Struct) ([]Query, error)
 				Typ:        goType(req, c),
 				SQLPackage: sqlpkg,
 			}
-		} else if len(query.Columns) > 1 {
+		} else if putOutColumns(query) {
 			var gs *Struct
 			var emit bool
 
@@ -254,6 +255,18 @@ func buildQueries(req *plugin.CodeGenRequest, structs []Struct) ([]Query, error)
 	return qs, nil
 }
 
+func putOutColumns(query *plugin.Query) bool {
+	if len(query.Columns) > 0 {
+		return true
+	}
+	for _, allowed := range []string{metadata.CmdMany, metadata.CmdOne, metadata.CmdBatchMany} {
+		if query.Cmd == allowed {
+			return true
+		}
+	}
+	return false
+}
+
 // It's possible that this method will generate duplicate JSON tag values
 //
 //	Columns: count, count,   count_2

internal/codegen/golang/result_test.go

@@ -0,0 +1,78 @@
+package golang
+
+import (
+	"testing"
+
+	"github.com/kyleconroy/sqlc/internal/metadata"
+	"github.com/kyleconroy/sqlc/internal/plugin"
+)
+
+func TestPutOutColumns_ForZeroColumns(t *testing.T) {
+	tests := []struct {
+		cmd  string
+		want bool
+	}{
+		{
+			cmd:  metadata.CmdExec,
+			want: false,
+		},
+		{
+			cmd:  metadata.CmdExecResult,
+			want: false,
+		},
+		{
+			cmd:  metadata.CmdExecRows,
+			want: false,
+		},
+		{
+			cmd:  metadata.CmdExecLastId,
+			want: false,
+		},
+		{
+			cmd:  metadata.CmdMany,
+			want: true,
+		},
+		{
+			cmd:  metadata.CmdOne,
+			want: true,
+		},
+		{
+			cmd:  metadata.CmdCopyFrom,
+			want: false,
+		},
+		{
+			cmd:  metadata.CmdBatchExec,
+			want: false,
+		},
+		{
+			cmd:  metadata.CmdBatchMany,
+			want: true,
+		},
+		{
+			cmd:  metadata.CmdBatchOne,
+			want: false,
+		},
+	}
+	for _, tc := range tests {
+		t.Run(tc.cmd, func(t *testing.T) {
+			query := &plugin.Query{
+				Cmd:     tc.cmd,
+				Columns: []*plugin.Column{},
+			}
+			got := putOutColumns(query)
+			if got != tc.want {
+				t.Errorf("putOutColumns failed. want %v, got %v", tc.want, got)
+			}
+		})
+	}
+}
+
+func TestPutOutColumns_AlwaysTrueWhenQueryHasColumns(t *testing.T) {
+	query := &plugin.Query{
+		Cmd:     metadata.CmdMany,
+		Columns: []*plugin.Column{{}},
+	}
+	if putOutColumns(query) != true {
+		t.Error("should be true when we have columns")
+	}
+}

internal/endtoend/testdata/select_empty_column_list/mysql/query.sql

@@ -0,0 +1,4 @@
+CREATE TABLE bar (name text);
+
+-- name: GetBars :many
+SELECT FROM bar;

internal/endtoend/testdata/select_empty_column_list/mysql/sqlc.json

@@ -0,0 +1,12 @@
+{
+  "version": "1",
+  "packages": [
+    {
+      "path": "go",
+      "engine": "mysql",
+      "name": "querytest",
+      "schema": "query.sql",
+      "queries": "query.sql"
+    }
+  ]
+}

internal/endtoend/testdata/select_empty_column_list/mysql/stderr.txt

@@ -0,0 +1,2 @@
+# package querytest
+query.sql:4:12: syntax error near "FROM bar;" "

internal/endtoend/testdata/select_empty_column_list/postgresql/pgx/go/db.go

@@ -0,0 +1,4 @@
+CREATE TABLE bar (id serial not null, name text);
+
+-- name: GetBars :many
+SELECT FROM bar LIMIT 5;

internal/endtoend/testdata/select_empty_column_list/postgresql/pgx/go/models.go

@@ -0,0 +1,13 @@
+{
+  "version": "1",
+  "packages": [
+    {
+      "path": "go",
+      "engine": "postgresql",
+      "sql_package": "pgx/v4",
+      "name": "querytest",
+      "schema": "query.sql",
+      "queries": "query.sql"
+    }
+  ]
+}