feat: Add the diff command

go.mod

@@ -5,6 +5,7 @@ go 1.19
 require (
 	github.com/antlr/antlr4/runtime/Go/antlr v0.0.0-20220626175859-9abda183db8e
 	github.com/bytecodealliance/wasmtime-go v1.0.0
+	github.com/cubicdaiya/gonp v1.0.4
 	github.com/davecgh/go-spew v1.1.1
 	github.com/go-sql-driver/mysql v1.6.0
 	github.com/google/go-cmp v0.5.9

go.sum

@@ -13,6 +13,8 @@ github.com/coreos/go-systemd v0.0.0-20190321100706-95778dfbb74e/go.mod h1:F5haX7
 github.com/coreos/go-systemd v0.0.0-20190719114852-fd7a80b32e1f/go.mod h1:F5haX7vjVVG0kc13fIWeqUViNPyEJxv/OmvnBo0Yme4=
 github.com/cpuguy83/go-md2man/v2 v2.0.2/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
 github.com/creack/pty v1.1.7/go.mod h1:lj5s0c3V2DBrqTV7llrYr5NG6My20zk30Fl46Y7DoTY=
+github.com/cubicdaiya/gonp v1.0.4 h1:ky2uIAJh81WiLcGKBVD5R7KsM/36W6IqqTy6Bo6rGws=
+github.com/cubicdaiya/gonp v1.0.4/go.mod h1:iWGuP/7+JVTn02OWhRemVbMmG1DOUnmrGTYYACpOI0I=
 github.com/cznic/mathutil v0.0.0-20181122101859-297441e03548 h1:iwZdTE0PVqJCos1vaoKsclOGD3ADKpshg3SRtYBbwso=
 github.com/cznic/mathutil v0.0.0-20181122101859-297441e03548/go.mod h1:e6NPNENfs9mPDVNRekM7lKScauxd5kXTr1Mfyig6TDM=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=

internal/cmd/cmd.go

@@ -1,6 +1,8 @@
 package cmd
 
 import (
+	"bufio"
+	"bytes"
 	"context"
 	"fmt"
 	"io"
@@ -9,6 +11,7 @@ import (
 	"path/filepath"
 	"runtime/trace"
 
+	"github.com/cubicdaiya/gonp"
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 	"gopkg.in/yaml.v3"
@@ -31,6 +34,7 @@ func Do(args []string, stdin io.Reader, stdout io.Writer, stderr io.Writer) int
 	rootCmd.PersistentFlags().BoolP("experimental", "x", false, "enable experimental features (default: false)")
 
 	rootCmd.AddCommand(checkCmd)
+	rootCmd.AddCommand(diffCmd)
 	rootCmd.AddCommand(genCmd)
 	rootCmd.AddCommand(initCmd)
 	rootCmd.AddCommand(versionCmd)
@@ -201,3 +205,48 @@ var checkCmd = &cobra.Command{
 		return nil
 	},
 }
+
+func getLines(f []byte) []string {
+	fp := bytes.NewReader(f)
+	scanner := bufio.NewScanner(fp)
+	lines := make([]string, 0)
+	for scanner.Scan() {
+		lines = append(lines, scanner.Text())
+	}
+	return lines
+}
+
+func filterHunks[T gonp.Elem](uniHunks []gonp.UniHunk[T]) []gonp.UniHunk[T] {
+	var out []gonp.UniHunk[T]
+	for i, uniHunk := range uniHunks {
+		var changed bool
+		for _, e := range uniHunk.GetChanges() {
+			switch e.GetType() {
+			case gonp.SesDelete:
+				changed = true
+			case gonp.SesAdd:
+				changed = true
+			}
+		}
+		if changed {
+			out = append(out, uniHunks[i])
+		}
+	}
+	return out
+}
+
+var diffCmd = &cobra.Command{
+	Use:   "diff",
+	Short: "Compare the generated files to the existing files",
+	RunE: func(cmd *cobra.Command, args []string) error {
+		if debug.Traced {
+			defer trace.StartRegion(cmd.Context(), "diff").End()
+		}
+		stderr := cmd.ErrOrStderr()
+		dir, name := getConfigPath(stderr, cmd.Flag("file"))
+		if err := Diff(cmd.Context(), ParseEnv(cmd), dir, name, stderr); err != nil {
+			os.Exit(1)
+		}
+		return nil
+	},
+}

internal/cmd/diff.go

@@ -0,0 +1,62 @@
+package cmd
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"runtime/trace"
+	"sort"
+	"strings"
+
+	"github.com/cubicdaiya/gonp"
+	"github.com/kyleconroy/sqlc/internal/debug"
+)
+
+func Diff(ctx context.Context, e Env, dir, name string, stderr io.Writer) error {
+	output, err := Generate(ctx, e, dir, name, stderr)
+	if err != nil {
+		return err
+	}
+	if debug.Traced {
+		defer trace.StartRegion(ctx, "checkfiles").End()
+	}
+	var errored bool
+
+	keys := make([]string, 0, len(output))
+	for k, _ := range output {
+		kk := k
+		keys = append(keys, kk)
+	}
+	sort.Strings(keys)
+
+	for _, filename := range keys {
+		source := output[filename]
+		if _, err := os.Stat(filename); errors.Is(err, os.ErrNotExist) {
+			errored = true
+			// stdout message
+			continue
+		}
+		existing, err := os.ReadFile(filename)
+		if err != nil {
+			errored = true
+			fmt.Fprintf(stderr, "%s: %s\n", filename, err)
+			continue
+		}
+		diff := gonp.New(getLines(existing), getLines([]byte(source)))
+		diff.Compose()
+		uniHunks := filterHunks(diff.UnifiedHunks())
+
+		if len(uniHunks) > 0 {
+			errored = true
+			fmt.Fprintf(stderr, "--- a%s\n", strings.TrimPrefix(filename, dir))
+			fmt.Fprintf(stderr, "+++ b%s\n", strings.TrimPrefix(filename, dir))
+			diff.FprintUniHunks(stderr, uniHunks)
+		}
+	}
+	if errored {
+		return errors.New("diff found")
+	}
+	return nil
+}

internal/endtoend/endtoend_test.go

@@ -3,6 +3,7 @@ package main
 import (
 	"bytes"
 	"context"
+	"encoding/json"
 	"os"
 	"path/filepath"
 	"strings"
@@ -92,14 +93,31 @@ func TestReplay(t *testing.T) {
 		tc := replay
 		t.Run(tc, func(t *testing.T) {
 			t.Parallel()
-			path, _ := filepath.Abs(tc)
+
 			var stderr bytes.Buffer
+			var output map[string]string
+			var err error
+
+			path, _ := filepath.Abs(tc)
+			args := parseExec(t, path)
 			expected := expectedStderr(t, path)
-			output, err := cmd.Generate(ctx, cmd.Env{ExperimentalFeatures: true}, path, "", &stderr)
+
+			switch args.Command {
+			case "diff":
+				err = cmd.Diff(ctx, cmd.Env{ExperimentalFeatures: true}, path, "", &stderr)
+			case "generate":
+				output, err = cmd.Generate(ctx, cmd.Env{ExperimentalFeatures: true}, path, "", &stderr)
+				if err == nil {
+					cmpDirectory(t, path, output)
+				}
+			default:
+				t.Fatalf("unknown command")
+			}
+
 			if len(expected) == 0 && err != nil {
-				t.Fatalf("sqlc generate failed: %s", stderr.String())
+				t.Fatalf("sqlc %s failed: %s", args.Command, stderr.String())
 			}
-			cmpDirectory(t, path, output)
+
 			if diff := cmp.Diff(expected, stderr.String()); diff != "" {
 				t.Errorf("stderr differed (-want +got):\n%s", diff)
 			}
@@ -179,6 +197,29 @@ func expectedStderr(t *testing.T, dir string) string {
 	return ""
 }
 
+type exec struct {
+	Command string `json:"command"`
+}
+
+func parseExec(t *testing.T, dir string) exec {
+	t.Helper()
+	var e exec
+	path := filepath.Join(dir, "exec.json")
+	if _, err := os.Stat(path); !os.IsNotExist(err) {
+		blob, err := os.ReadFile(path)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if err := json.Unmarshal(blob, &e); err != nil {
+			t.Fatal(err)
+		}
+	}
+	if e.Command == "" {
+		e.Command = "generate"
+	}
+	return e
+}
+
 func BenchmarkReplay(b *testing.B) {
 	ctx := context.Background()
 	var dirs []string

internal/endtoend/testdata/diff_no_output/exec.json

@@ -0,0 +1,3 @@
+{
+  "command": "diff"
+}

internal/endtoend/testdata/diff_no_output/query.sql

@@ -0,0 +1,18 @@
+-- name: GetAuthor :one
+SELECT * FROM authors
+WHERE id = $1 LIMIT 1;
+
+-- name: ListAuthors :many
+SELECT * FROM authors
+ORDER BY bio;
+
+-- name: SelectOne :one
+SELECT 1;
+
+-- name: CreateAuthor :one
+INSERT INTO authors (
+          name, bio
+) VALUES (
+  $1, $2
+)
+RETURNING *;

internal/endtoend/testdata/diff_no_output/schema.sql

@@ -0,0 +1,11 @@
+CREATE TABLE authors (
+          id   BIGSERIAL PRIMARY KEY,
+          name text      NOT NULL,
+          bio  text
+);
+
+CREATE TABLE books (
+          id    BIGSERIAL PRIMARY KEY,
+          title text      NOT NULL
+);
+