Handle --output-dir query filename collisions

Occurs when the base names are the same like with:

- alpha/query.sql
- bravo/query.sql

As a first attempt to dedupe, we'll add the parent directory as a suffix, like
"alpha_query.sql.go". That won't work for cases like:

- alpha/query.sql
- parent/alpha/query.sql

In those cases, append an incrementing numeric literal:

- alpha_query.sql.0.go
- alpha_query.sql.1.go

Fixes #28.

example/acceptance_test.go

@@ -139,6 +139,16 @@ func TestExamples(t *testing.T) {
 				"--query-glob", "example/pgcrypto/query.sql",
 			},
 		},
+		{
+			name: "example/separate_out_dir",
+			args: []string{
+				"--schema-glob", "example/separate_out_dir/schema.sql",
+				"--query-glob", "example/separate_out_dir/alpha/query.sql",
+				"--query-glob", "example/separate_out_dir/alpha/alpha/query.sql",
+				"--query-glob", "example/separate_out_dir/bravo/query.sql",
+				"--output-dir", "example/separate_out_dir/out",
+			},
+		},
 		{
 			name: "example/void",
 			args: []string{

example/separate_out_dir/README.md

@@ -0,0 +1,4 @@
+# Example using a separate output dir
+
+This example shows how to use the `--output-dir` flag to control where pggen
+writes query output files.

example/separate_out_dir/alpha/alpha/query.sql

@@ -0,0 +1,2 @@
+-- name: AlphaNested :one
+SELECT 'alpha_nested' as output;

example/separate_out_dir/alpha/query.sql

@@ -0,0 +1,2 @@
+-- name: Alpha :one
+SELECT 'alpha' as output;

example/separate_out_dir/bravo/query.sql

@@ -0,0 +1,2 @@
+-- name: Bravo :one
+SELECT 'bravo' as output;

example/separate_out_dir/out/codegen_test.go

@@ -0,0 +1,55 @@
+package out
+
+import (
+	"github.com/jschaf/pggen"
+	"github.com/jschaf/pggen/internal/pgtest"
+	"github.com/stretchr/testify/assert"
+	"io/ioutil"
+	"path/filepath"
+	"testing"
+)
+
+func TestGenerate_Go_Example_SeparateOutDir(t *testing.T) {
+	conn, cleanupFunc := pgtest.NewPostgresSchema(t, []string{
+		"../schema.sql",
+	})
+	defer cleanupFunc()
+
+	tmpDir := t.TempDir()
+	err := pggen.Generate(
+		pggen.GenerateOptions{
+			ConnString: conn.Config().ConnString(),
+			QueryFiles: []string{
+				"../alpha/query.sql",
+				"../alpha/alpha/query.sql",
+				"../bravo/query.sql",
+			},
+			OutputDir: tmpDir,
+			GoPackage: "out",
+			Language:  pggen.LangGo,
+		})
+	if err != nil {
+		t.Fatalf("Generate(): %s", err)
+	}
+
+	for _, file := range []string{
+		"alpha_query.sql.0.go",
+		"alpha_query.sql.1.go",
+		"bravo_query.sql.go",
+	} {
+		wantQueries, err := ioutil.ReadFile(file)
+		if err != nil {
+			t.Fatalf("read wanted file %s: %s", file, err)
+		}
+
+		gotFile := filepath.Join(tmpDir, file)
+		assert.FileExists(t, gotFile, "Generate() should emit "+file)
+		gotQueries, err := ioutil.ReadFile(gotFile)
+		if err != nil {
+			t.Fatalf("read generated %s: %s", file, err)
+		}
+		assert.Equalf(t, string(wantQueries), string(gotQueries),
+			"Got file %s; does not match contents of file %s",
+			gotFile, file)
+	}
+}

example/separate_out_dir/out/query.sql_test.go

@@ -0,0 +1,35 @@
+package out
+
+import (
+	"context"
+	"github.com/stretchr/testify/require"
+	"testing"
+
+	"github.com/jschaf/pggen/internal/pgtest"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNewQuerier_FindAuthorByID(t *testing.T) {
+	conn, cleanup := pgtest.NewPostgresSchema(t, []string{"../schema.sql"})
+	defer cleanup()
+
+	q := NewQuerier(conn)
+
+	t.Run("AlphaNested", func(t *testing.T) {
+		got, err := q.AlphaNested(context.Background())
+		require.NoError(t, err)
+		assert.Equal(t, "alpha_nested", got)
+	})
+
+	t.Run("Alpha", func(t *testing.T) {
+		got, err := q.Alpha(context.Background())
+		require.NoError(t, err)
+		assert.Equal(t, "alpha", got)
+	})
+
+	t.Run("Bravo", func(t *testing.T) {
+		got, err := q.Bravo(context.Background())
+		require.NoError(t, err)
+		assert.Equal(t, "bravo", got)
+	})
+}

example/separate_out_dir/schema.sql

@@ -0,0 +1,7 @@
+CREATE TABLE alpha (
+  key text NOT NULL PRIMARY KEY
+);
+
+CREATE TABLE bravo (
+  key text NOT NULL PRIMARY KEY
+);