bake: fix BUILDX_BAKE_FILE env behavior

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>

commands/bake.go

@@ -465,12 +465,12 @@ func bakeCmd(dockerCli command.Cli, rootOpts *rootOptions) *cobra.Command {
 		RunE: func(cmd *cobra.Command, args []string) error {
 			filesFromEnv := false
 			if len(options.files) == 0 {
-				envFiles, err := bakeEnvFiles(os.LookupEnv)
-				if err != nil {
+				if envFiles, err := bakeEnvFiles(os.LookupEnv); err != nil {
 					return err
+				} else if len(envFiles) > 0 {
+					options.files = envFiles
+					filesFromEnv = true
 				}
-				options.files = envFiles
-				filesFromEnv = true
 			}
 			// reset to nil to avoid override is unset
 			if !cmd.Flags().Lookup("no-cache").Changed {

tests/bake.go

@@ -2204,6 +2204,22 @@ target "second" {
 }
 `)
 
+	t.Run("no env", func(t *testing.T) {
+		dir := tmpdir(t,
+			fstest.CreateFile("docker-bake.hcl", bakeFileFirst, 0600),
+			fstest.CreateFile("first", []byte("first"), 0600),
+		)
+		cmd := buildxCmd(sb,
+			withDir(dir),
+			withArgs("bake", "--progress=plain", "first"))
+
+		dt, err := cmd.CombinedOutput()
+		require.NoError(t, err, string(dt))
+		require.Contains(t, string(dt), `#1 [internal] load local bake definitions`)
+		require.NotContains(t, string(dt), `from BUILDX_BAKE_FILE env`)
+		require.Contains(t, string(dt), `#1 reading docker-bake.hcl`)
+	})
+
 	t.Run("single file", func(t *testing.T) {
 		dir := tmpdir(t,
 			fstest.CreateFile("first.hcl", bakeFileFirst, 0600),