cmd/cue: add version to module.cue file

We build on https://cuelang.org/cl/1173894 by providing the
version when available. We now support the `$CUE_VERSION_OVERRIDE`
environment variable mainly for testing, but also because it might
potentially be useful in the future.

Signed-off-by: Roger Peppe <rogpeppe@gmail.com>
Change-Id: I081a056864a28456b3a8f63fdbdb14482649ac4d
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1176194
Unity-Result: CUE porcuepine <cue.porcuepine@gmail.com>
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>

cmd/cue/cmd/modtidy.go

@@ -22,6 +22,7 @@ import (
 	"path/filepath"
 
 	"github.com/spf13/cobra"
+	gomodule "golang.org/x/mod/module"
 
 	"cuelang.org/go/internal/mod/modload"
 )
@@ -58,7 +59,17 @@ func runModTidy(cmd *Command, args []string) error {
 	if err != nil {
 		return err
 	}
-	mf, err := modload.Tidy(ctx, os.DirFS(modRoot), ".", reg, "")
+	bi, _ := readBuildInfo()
+	version := cueVersion(bi)
+	if gomodule.IsPseudoVersion(version) {
+		// If we have a version like v0.7.1-0.20240130142347-7855e15cb701
+		// we want it to turn into the base version (v0.7.0 in that example).
+		// If there's no base version (e.g. v0.0.0-...) then PseudoVersionBase
+		// will return the empty string, which is exactly what we want
+		// because we don't want to put v0.0.0 in a module.cue file.
+		version, _ = gomodule.PseudoVersionBase(version)
+	}
+	mf, err := modload.Tidy(ctx, os.DirFS(modRoot), ".", reg, version)
 	if err != nil {
 		return err
 	}

cmd/cue/cmd/testdata/script/modtidy_with_existing_version.txtar

@@ -0,0 +1,35 @@
+# Check that cue mod tidy won't change the language
+# version when the field is already present in the module.cue file.
+
+env CUE_VERSION_OVERRIDE=v0.9.9
+exec cue mod tidy
+cmp cue.mod/module.cue want-module
+
+
+# Check that the resulting module evaluates as expected.
+exec cue export .
+cmp stdout want-stdout
+-- want-stdout --
+{
+    "x": 1
+}
+-- want-module --
+module: "main.org@v0"
+language: {
+	version: "v0.1.2"
+}
+-- cue.mod/module.cue --
+module: "main.org@v0"
+language: {
+	version: "v0.1.2"
+}
+
+-- main.cue --
+package main
+x: 1
+
+-- _registry/example.com_v0.0.1/cue.mod/module.cue --
+module: "example.com@v0"
+
+-- _registry/example.com_v0.0.1/top.cue --
+package main

cmd/cue/cmd/testdata/script/modtidy_with_pseudoversion.txtar

@@ -0,0 +1,31 @@
+# Check that cue mod tidy chooses a correct base version
+# when provided with a pseudo-version.
+
+env CUE_VERSION_OVERRIDE=v0.7.1-0.20240130142347-7855e15cb701
+exec cue mod tidy
+cmp cue.mod/module.cue want-module
+
+# Check that the resulting module evaluates as expected.
+exec cue export .
+cmp stdout want-stdout
+-- want-stdout --
+{
+    "x": 1
+}
+-- want-module --
+module: "main.org@v0"
+language: {
+	version: "v0.7.0"
+}
+-- cue.mod/module.cue --
+module: "main.org@v0"
+
+-- main.cue --
+package main
+x: 1
+
+-- _registry/example.com_v0.0.1/cue.mod/module.cue --
+module: "example.com@v0"
+
+-- _registry/example.com_v0.0.1/top.cue --
+package main

cmd/cue/cmd/testdata/script/modtidy_with_vcsinfo.txtar

@@ -0,0 +1,29 @@
+# Check that cue mod tidy does not add the language version
+# to the module.cue file when it's a dev version created
+# by cue-internal logic.
+
+env CUE_VERSION_TEST_CFG='[{"Key":"vcs","Value":"git"},{"Key":"vcs.revision","Value":"47b7032385cb490fab7d47b89fca36835cf13d39"},{"Key":"vcs.time","Value":"2022-05-10T04:58:46Z"},{"Key":"vcs.modified","Value":"true"}]'
+exec cue mod tidy
+cmp cue.mod/module.cue want-module
+
+# Check that the resulting module evaluates as expected.
+exec cue export .
+cmp stdout want-stdout
+-- want-stdout --
+{
+    "x": 1
+}
+-- want-module --
+module: "main.org@v0"
+-- cue.mod/module.cue --
+module: "main.org@v0"
+
+-- main.cue --
+package main
+x: 1
+
+-- _registry/example.com_v0.0.1/cue.mod/module.cue --
+module: "example.com@v0"
+
+-- _registry/example.com_v0.0.1/top.cue --
+package main

cmd/cue/cmd/testdata/script/modtidy_with_version.txtar

@@ -0,0 +1,36 @@
+# Check that cue mod tidy adds the language version to the
+# module.cue file when there is one. Note that because
+# the version is taken from the build info, we need to use
+# the CUE_VERSION_OVERRIDE environment variable.
+# We get confidence in the actual buildinfo logic because exactly
+# the same code is used behind the scenes for the `cue version`
+# implementation too.
+
+env CUE_VERSION_OVERRIDE=v0.1.2
+exec cue mod tidy
+cmp cue.mod/module.cue want-module
+
+# Check that the resulting module evaluates as expected.
+exec cue export .
+cmp stdout want-stdout
+-- want-stdout --
+{
+    "x": 1
+}
+-- want-module --
+module: "main.org@v0"
+language: {
+	version: "v0.1.2"
+}
+-- cue.mod/module.cue --
+module: "main.org@v0"
+
+-- main.cue --
+package main
+x: 1
+
+-- _registry/example.com_v0.0.1/cue.mod/module.cue --
+module: "example.com@v0"
+
+-- _registry/example.com_v0.0.1/top.cue --
+package main

cmd/cue/cmd/version.go

@@ -39,65 +39,28 @@ func newVersionCmd(c *Command) *cobra.Command {
 
 const defaultVersion = "(devel)"
 
-// version be set by a builder using
+// version can be set by a builder using
 // -ldflags='-X cuelang.org/go/cmd/cue/cmd.version=<version>'.
 // However, people should prefer building via a mechanism which
 // resolves cuelang.org/go as a dependency (and not the main
 // module), in which case the version information is determined
 // from the *debug.BuildInfo (see below). So this mechanism is
-// really considered legacy.
-var version = defaultVersion
+// considered legacy.
+var version string
 
 func runVersion(cmd *Command, args []string) error {
 	w := cmd.OutOrStdout()
+
 	// read in build info
-	bi, ok := debug.ReadBuildInfo()
+	bi, ok := readBuildInfo()
 	if !ok {
 		// shouldn't happen
 		return errors.New("unknown error reading build-info")
 	}
-
-	// test-based overrides
-	if v := os.Getenv("CUE_VERSION_TEST_CFG"); v != "" {
-		var extra []debug.BuildSetting
-		if err := json.Unmarshal([]byte(v), &extra); err != nil {
-			return err
-		}
-		bi.Settings = append(bi.Settings, extra...)
+	version := cueVersion(bi)
+	if version == "" {
+		version = defaultVersion
 	}
-
-	// prefer ldflags `version` override
-	if version == defaultVersion {
-		// no version provided via ldflags, try buildinfo
-		if bi.Main.Version != "" && bi.Main.Version != defaultVersion {
-			version = bi.Main.Version
-		}
-	}
-
-	if version == defaultVersion {
-		// a specific version was not provided by ldflags or buildInfo
-		// attempt to make our own
-		var vcsTime time.Time
-		var vcsRevision string
-		for _, s := range bi.Settings {
-			switch s.Key {
-			case "vcs.time":
-				// If the format is invalid, we'll print a zero timestamp.
-				vcsTime, _ = time.Parse(time.RFC3339Nano, s.Value)
-			case "vcs.revision":
-				vcsRevision = s.Value
-				// module.PseudoVersion recommends the revision to be a 12-byte
-				// commit hash prefix, which is what cmd/go uses as well.
-				if len(vcsRevision) > 12 {
-					vcsRevision = vcsRevision[:12]
-				}
-			}
-		}
-		if vcsRevision != "" {
-			version = module.PseudoVersion("", "", vcsTime, vcsRevision)
-		}
-	}
-
 	fmt.Fprintf(w, "cue version %s\n\n", version)
 	fmt.Fprintf(w, "go version %s\n", runtime.Version())
 	for _, s := range bi.Settings {
@@ -115,3 +78,66 @@ func runVersion(cmd *Command, args []string) error {
 	}
 	return nil
 }
+
+// cueVersion returns the version of the CUE module as much
+// as can reasonably be determined. If no version can be
+// determined, it returns the empty string.
+func cueVersion(bi *debug.BuildInfo) string {
+	if v := os.Getenv("CUE_VERSION_OVERRIDE"); v != "" && inTest {
+		return v
+	}
+	v := version
+	if v != "" {
+		// The global version variable has been
+		// configured via ldflags.
+		return v
+	}
+	if bi == nil {
+		return ""
+	}
+	if bi.Main.Version != "" && bi.Main.Version != defaultVersion {
+		v = bi.Main.Version
+	}
+	if v != "" {
+		return v
+	}
+	// a specific version was not provided by ldflags or buildInfo
+	// attempt to make our own
+	var vcsTime time.Time
+	var vcsRevision string
+	for _, s := range bi.Settings {
+		switch s.Key {
+		case "vcs.time":
+			// If the format is invalid, we'll print a zero timestamp.
+			vcsTime, _ = time.Parse(time.RFC3339Nano, s.Value)
+		case "vcs.revision":
+			vcsRevision = s.Value
+			// module.PseudoVersion recommends the revision to be a 12-byte
+			// commit hash prefix, which is what cmd/go uses as well.
+			if len(vcsRevision) > 12 {
+				vcsRevision = vcsRevision[:12]
+			}
+		}
+	}
+	if vcsRevision != "" {
+		return module.PseudoVersion("", "", vcsTime, vcsRevision)
+	}
+	return ""
+}
+
+func readBuildInfo() (*debug.BuildInfo, bool) {
+	bi, ok := debug.ReadBuildInfo()
+	if !ok || !inTest {
+		return bi, ok
+	}
+	// test-based overrides
+	if v := os.Getenv("CUE_VERSION_TEST_CFG"); v != "" {
+		var extra []debug.BuildSetting
+		if err := json.Unmarshal([]byte(v), &extra); err != nil {
+			// It's only for tests, so panic is OK.
+			panic(err)
+		}
+		bi.Settings = append(bi.Settings, extra...)
+	}
+	return bi, true
+}