cmd: Adding --v0-compatible flag (#7065)

To make OPA behave as v0.x post v1.0 release.
If used simultaneously with `--v1-compatible` flag, the `--v0-compatible` flag takes precedence.

Also, future-proofing `cmd` package tests for 1.0.

Signed-off-by: Johan Fylling <johan.dev@fylling.se>

ast/parser.go

@@ -2696,18 +2696,19 @@ func (p *Parser) regoV1Import(imp *Import) {
 		return
 	}
 
-	if p.po.RegoVersion == RegoV1 {
-		// We're parsing for Rego v1, where the 'rego.v1' import is a no-op.
-		return
-	}
-
 	path := imp.Path.Value.(Ref)
 
+	// v1 is only valid option
 	if len(path) == 1 || !path[1].Equal(RegoV1CompatibleRef[1]) || len(path) > 2 {
 		p.errorf(imp.Path.Location, "invalid import `%s`, must be `%s`", path, RegoV1CompatibleRef)
 		return
 	}
 
+	if p.po.RegoVersion == RegoV1 {
+		// We're parsing for Rego v1, where the 'rego.v1' import is a no-op.
+		return
+	}
+
 	if imp.Alias != "" {
 		p.errorf(imp.Path.Location, "`rego` imports cannot be aliased")
 		return

cmd/bench.go

@@ -124,6 +124,7 @@ The optional "gobench" output format conforms to the Go Benchmark Data Format.
 	addIgnoreFlag(benchCommand.Flags(), &params.ignore)
 	addSchemaFlags(benchCommand.Flags(), params.schema)
 	addTargetFlag(benchCommand.Flags(), params.target)
+	addV0CompatibleFlag(benchCommand.Flags(), &params.v0Compatible, false)
 	addV1CompatibleFlag(benchCommand.Flags(), &params.v1Compatible, false)
 
 	// Shared benchmark flags
@@ -304,6 +305,7 @@ func benchE2E(ctx context.Context, args []string, params benchmarkCommandParams,
 		GracefulShutdownPeriod: params.gracefulShutdownPeriod,
 		ShutdownWaitPeriod:     params.shutdownWaitPeriod,
 		ConfigFile:             params.configFile,
+		V0Compatible:           params.v0Compatible,
 		V1Compatible:           params.v1Compatible,
 	}
 

cmd/bench_test.go

@@ -683,8 +683,9 @@ func TestBenchMainWithDataE2E(t *testing.T) {
 	params.e2e = true
 
 	mod := `package a.b
+	import rego.v1
 
-	x {
+	x if {
 	   data.a.b.c == 42
 	}
 	`
@@ -731,25 +732,28 @@ func TestBenchMainBadQueryE2E(t *testing.T) {
 	}
 }
 
-func TestBenchMainV1Compatible(t *testing.T) {
+func TestBenchMainCompatibleFlags(t *testing.T) {
 	tests := []struct {
 		note         string
+		v0Compatible bool
 		v1Compatible bool
 		module       string
 		query        string
 		expErrs      []string
 	}{
 		// These tests are slow, so we're not being completely exhaustive here.
 		{
-			note: "v0.x, keywords not used",
+			note:         "v0, keywords not used",
+			v0Compatible: true,
 			module: `package test
 a[4] {
 	1 == 1
 }`,
 			query: `data.test.a`,
 		},
 		{
-			note: "v0.x, no keywords imported",
+			note:         "v0, no keywords imported",
+			v0Compatible: true,
 			module: `package test
 a contains 4 if {
 	1 == 1
@@ -761,7 +765,7 @@ a contains 4 if {
 			},
 		},
 		{
-			note:         "v1.0, keywords not used",
+			note:         "v1, keywords not used",
 			v1Compatible: true,
 			module: `package test
 a[4] {
@@ -774,11 +778,21 @@ a[4] {
 			},
 		},
 		{
-			note:         "v1.0, no keywords imported",
+			note:         "v1, no keywords imported",
 			v1Compatible: true,
 			module: `package test
 a contains 4 if {
 	1 == 1
+}`,
+			query: `data.test.a`,
+		},
+		{
+			note:         "v0+v1, keywords not used (v0 takes precedence)",
+			v0Compatible: true,
+			v1Compatible: true,
+			module: `package test
+a[4] {
+	1 == 1
 }`,
 			query: `data.test.a`,
 		},
@@ -807,6 +821,7 @@ a contains 4 if {
 				test.WithTempFS(files, func(path string) {
 					params := testBenchParams()
 					_ = params.outputFormat.Set(evalPrettyOutput)
+					params.v0Compatible = tc.v0Compatible
 					params.v1Compatible = tc.v1Compatible
 					params.e2e = mode.e2e
 
@@ -1303,8 +1318,9 @@ func fakeBenchResults() testing.BenchmarkResult {
 
 func testBundle() bundle.Bundle {
 	mod := `package a.b
+	import rego.v1
 
-	x {
+	x if {
 	   data.a.b.c == 42
 	}
 	`

cmd/build.go

@@ -44,6 +44,7 @@ type buildParams struct {
 	excludeVerifyFiles []string
 	plugin             string
 	ns                 string
+	v0Compatible       bool
 	v1Compatible       bool
 	followSymlinks     bool
 }
@@ -257,6 +258,7 @@ against OPA v0.22.0:
 	addSigningPluginFlag(buildCommand.Flags(), &buildParams.plugin)
 	addClaimsFileFlag(buildCommand.Flags(), &buildParams.claimsFile)
 
+	addV0CompatibleFlag(buildCommand.Flags(), &buildParams.v0Compatible, false)
 	addV1CompatibleFlag(buildCommand.Flags(), &buildParams.v1Compatible, false)
 
 	RootCommand.AddCommand(buildCommand)
@@ -307,9 +309,14 @@ func dobuild(params buildParams, args []string) error {
 		WithPartialNamespace(params.ns).
 		WithFollowSymlinks(params.followSymlinks)
 
-	if params.v1Compatible {
-		compiler = compiler.WithRegoVersion(ast.RegoV1)
+	regoVersion := ast.DefaultRegoVersion
+	if params.v0Compatible {
+		// v0 takes precedence over v1
+		regoVersion = ast.RegoV0
+	} else if params.v1Compatible {
+		regoVersion = ast.RegoV1
 	}
+	compiler = compiler.WithRegoVersion(regoVersion)
 
 	if params.revision.isSet {
 		compiler = compiler.WithRevision(*params.revision.v)