Add a version field to buildscripts.

internal/runbits/buildscript/buildscript_test.go

@@ -30,7 +30,9 @@ func TestDiff(t *testing.T) {
 	)
 
 in:
-	runtime`))
+	runtime
+
+version: 1`))
 	require.NoError(t, err)
 
 	// Make a copy of the original expression.
@@ -64,7 +66,9 @@ in:
 	)
 
 in:
-	runtime`, result)
+	runtime
+
+version: 1`, result)
 }
 
 // TestRealWorld tests a real-world case where:
@@ -130,5 +134,7 @@ func TestRealWorld(t *testing.T) {
 	)
 
 in:
-	runtime`, result)
+	runtime
+
+version: 1`, result)
 }

internal/runbits/buildscript/testdata/buildscript1.yaml

@@ -33,4 +33,6 @@ let:
 	)
 
 in:
-	runtime
+	runtime
+
+version: 1

internal/runbits/buildscript/testdata/buildscript2.yaml

@@ -39,4 +39,6 @@ let:
 	)
 
 in:
-	runtime
+	runtime
+
+version: 1

pkg/platform/runtime/buildexpression/merge/merge_test.go

@@ -32,7 +32,9 @@ func TestMergeAdd(t *testing.T) {
 	)
 
 in:
-	runtime`))
+	runtime
+
+version: 1`))
 	require.NoError(t, err)
 	bytes, err := json.Marshal(scriptA)
 	require.NoError(t, err)
@@ -59,7 +61,9 @@ in:
 	)
 
 in:
-	runtime`))
+	runtime
+
+version: 1`))
 	require.NoError(t, err)
 	bytes, err = json.Marshal(scriptB)
 	require.NoError(t, err)
@@ -104,7 +108,9 @@ in:
 	)
 
 in:
-	runtime`, mergedScript.String())
+	runtime
+
+version: 1`, mergedScript.String())
 }
 
 func TestMergeRemove(t *testing.T) {
@@ -132,7 +138,9 @@ func TestMergeRemove(t *testing.T) {
 	)
 
 in:
-	runtime`))
+	runtime
+
+version: 1`))
 	require.NoError(t, err)
 	bytes, err := json.Marshal(scriptA)
 	require.NoError(t, err)
@@ -159,7 +167,9 @@ in:
 	)
 
 in:
-	runtime`))
+	runtime
+
+version: 1`))
 	require.NoError(t, err)
 	bytes, err = json.Marshal(scriptB)
 	require.NoError(t, err)
@@ -200,7 +210,9 @@ in:
 	)
 
 in:
-	runtime`, mergedScript.String())
+	runtime
+
+version: 1`, mergedScript.String())
 }
 
 func TestMergeConflict(t *testing.T) {
@@ -220,7 +232,9 @@ func TestMergeConflict(t *testing.T) {
 	)
 
 in:
-	runtime`))
+	runtime
+
+version: 1`))
 	require.NoError(t, err)
 	bytes, err := json.Marshal(scriptA)
 	require.NoError(t, err)
@@ -246,7 +260,9 @@ in:
 	)
 
 in:
-	runtime`))
+	runtime
+
+version: 1`))
 	require.NoError(t, err)
 	bytes, err = json.Marshal(scriptB)
 	require.NoError(t, err)

pkg/platform/runtime/buildscript/buildscript.go

@@ -14,15 +14,19 @@ import (
 	"github.com/alecthomas/participle/v2"
 )
 
+// Version is the current buildscript version.
+const CurrentVersion int = 1
+
 // Script's tagged fields will be initially filled in by Participle.
 // Expr will be constructed later and is this script's buildexpression. We keep a copy of the build
 // expression here with any changes that have been applied before either writing it to disk or
 // submitting it to the build planner. It's easier to operate on build expressions directly than to
 // modify or manually populate the Participle-produced fields and re-generate a build expression.
 type Script struct {
-	Let  *Let `parser:"'let' ':' @@"`
-	In   *In  `parser:"'in' ':' @@"`
-	Expr *buildexpression.BuildExpression
+	Let     *Let `parser:"'let' ':' @@"`
+	In      *In  `parser:"'in' ':' @@"`
+	Expr    *buildexpression.BuildExpression
+	Version int `parser:"'version' ':' @Int"`
 }
 
 type Let struct {
@@ -82,11 +86,23 @@ func NewScript(data []byte) (*Script, error) {
 	}
 	script.Expr = expr
 
+	// Migrate from older buildscript versions if necessary.
+	if script.Version < CurrentVersion {
+		err := migrateOldBuildScript(script)
+		if err != nil {
+			return nil, errs.Wrap(err, "Unable to migrate old build script")
+		}
+	}
+
 	return script, nil
 }
 
+func migrateOldBuildScript(script *Script) error {
+	return nil // Noop for now until we need to migrate
+}
+
 func NewScriptFromBuildExpression(expr *buildexpression.BuildExpression) (*Script, error) {
-	return &Script{Expr: expr}, nil
+	return &Script{Expr: expr, Version: CurrentVersion}, nil
 }
 
 func indent(s string) string {
@@ -108,6 +124,9 @@ func (s *Script) String() string {
 	case s.Expr.Let.In.Name != nil:
 		buf.WriteString(indent(*s.Expr.Let.In.Name))
 	}
+	buf.WriteString("\n\n")
+	buf.WriteString("version: ")
+	buf.WriteString(strconv.Itoa(s.Version))
 	return buf.String()
 }
 

pkg/platform/runtime/buildscript/buildscript_test.go

@@ -48,6 +48,7 @@ func TestBasic(t *testing.T) {
   )
 in:
   runtime
+version: 1
 `))
 	require.NoError(t, err)
 
@@ -89,6 +90,7 @@ in:
 		},
 		&In{Name: ptr.To("runtime")},
 		expr,
+		1,
 	}, script)
 }
 
@@ -117,6 +119,8 @@ in:
         win_installer(win_runtime),
         tar_installer(linux_runtime)
     )
+
+version: 1
 `))
 	require.NoError(t, err)
 
@@ -165,6 +169,7 @@ in:
 			{FuncCall: &FuncCall{"tar_installer", []*Value{{Ident: ptr.To("linux_runtime")}}}},
 		}}},
 		expr,
+		1,
 	}, script)
 }
 
@@ -191,7 +196,8 @@ const example = `let:
     solver_version = 0
   )
 in:
-  runtime`
+  runtime
+version: 1`
 
 func TestExample(t *testing.T) {
 	script, err := NewScript([]byte(example))
@@ -241,6 +247,7 @@ func TestExample(t *testing.T) {
 		},
 		&In{Name: ptr.To("runtime")},
 		expr,
+		1,
 	}, script)
 }
 
@@ -253,6 +260,7 @@ func TestString(t *testing.T) {
     )
 in:
     runtime
+version: 1
 `))
 	require.NoError(t, err)
 
@@ -271,7 +279,9 @@ in:
 	)
 
 in:
-	runtime`, script.String())
+	runtime
+
+version: 1`, script.String())
 }
 
 func TestRoundTrip(t *testing.T) {
@@ -304,6 +314,7 @@ func TestJson(t *testing.T) {
     )
 in:
     runtime
+version: 1
 `))
 	require.NoError(t, err)
 
@@ -386,6 +397,7 @@ func TestBuildExpression(t *testing.T) {
 	script, err := NewScriptFromBuildExpression(expr)
 	require.NoError(t, err)
 	require.NotNil(t, script)
+	assert.Equal(t, CurrentVersion, script.Version)
 	newExpr := script.Expr
 	exprBytes, err := json.Marshal(expr)
 	require.NoError(t, err)