internal/mod/modpkgload: support packages without major versions

When there's no major version in a package import
path, try to find one from the requirements.

Signed-off-by: Roger Peppe <[email protected]>
Change-Id: Iceee9a0589d5b23748c07ef64c2815a853ae0041
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1173323
Reviewed-by: Daniel Martí <[email protected]>
Unity-Result: CUE porcuepine <[email protected]>
TryBot-Result: CUEcueckoo <[email protected]>

internal/mod/modpkgload/import.go

@@ -41,9 +41,9 @@ func (pkgs *Packages) importFromModules(ctx context.Context, pkgPath string) (m
 	// take it from requirements; if not present there, search for latest
 	// major version and use that. What should we do when there are
 	// several major versions present in the go.mod file?
-	pkgPathOnly, pkgVersion, ok := module.SplitPathVersion(pkgPath)
-	if !ok {
-		return failf("all imports must currently be qualified with a major version")
+	pkgPathOnly, pkgVersion, hasMajor := module.SplitPathVersion(pkgPath)
+	if !hasMajor {
+		pkgPathOnly = pkgPath
 	}
 	if filepath.IsAbs(pkgPathOnly) || path.IsAbs(pkgPathOnly) {
 		return failf("%q is not a package path", pkgPath)
@@ -82,6 +82,12 @@ func (pkgs *Packages) importFromModules(ctx context.Context, pkgPath string) (m
 				v  string
 				ok bool
 			)
+			pkgVersion := pkgVersion
+			if !hasMajor {
+				if pkgVersion, _ = pkgs.requirements.DefaultMajorVersion(prefix); pkgVersion == "" {
+					continue
+				}
+			}
 			prefixPath := prefix + "@" + pkgVersion
 			if mg == nil {
 				v, ok = pkgs.requirements.RootSelected(prefixPath)

internal/mod/modpkgload/pkgload_test.go

@@ -41,7 +41,13 @@ func TestLoadPackages(t *testing.T) {
 
 				initialRequirementsStr := strings.Fields(readTestFile("initial-requirements"))
 				mainModulePath, moduleVersions := initialRequirementsStr[0], mapSlice(initialRequirementsStr[1:], module.MustParseVersion)
-				initialRequirements := modrequirements.NewRequirements(mainModulePath, reg, moduleVersions, nil)
+				defaultMajorVersions := make(map[string]string)
+				for _, f := range strings.Fields(readTestFile("default-major-versions")) {
+					p, v, ok := strings.Cut(f, "@")
+					qt.Assert(t, qt.IsTrue(ok))
+					defaultMajorVersions[p] = v
+				}
+				initialRequirements := modrequirements.NewRequirements(mainModulePath, reg, moduleVersions, defaultMajorVersions)
 
 				rootPackages := strings.Fields(readTestFile("root-packages"))
 				want := readTestFile("want")

internal/mod/modpkgload/testdata/simple.txtar

@@ -2,6 +2,7 @@
 main.test@v0
 -- test0/root-packages --
 main.test@v0
+-- test0/default-major-versions --
 -- test0/want --
 main.test@v0
 	flags: inAll,isRoot,fromRoot,importsLoaded
@@ -18,6 +19,7 @@ main.test@v0
 [email protected]
 -- test1/root-packages --
 main.test@v0
+-- test1/default-major-versions --
 -- test1/want --
 main.test@v0
 	flags: inAll,isRoot,fromRoot,importsLoaded

internal/mod/modpkgload/testdata/withdefaultmajorversions.txtar

@@ -0,0 +1,37 @@
+-- test0/initial-requirements --
+main.test@v0 [email protected]
+-- test0/root-packages --
+main.test@v0
+example.com/blah
+-- test0/default-major-versions --
+example.com@v0
+-- test0/want --
+main.test@v0
+	flags: inAll,isRoot,fromRoot,importsLoaded
+	mod: main.test@v0
+	location: .
+	imports:
+		example.com/blah
+example.com/blah
+	flags: inAll,isRoot,fromRoot,importsLoaded
+	mod: [email protected]
+	location: _registry/example.com_v0.0.1/blah
+	imports:
+		foo.com/bar/hello/goodbye@v0
+foo.com/bar/hello/goodbye@v0
+	flags: inAll,isRoot,fromRoot
+	error: cannot fetch foo.com/bar/[email protected]: module foo.com/bar/[email protected] not found at _registry/foo.com_bar_hello_v0.2.3
+	missing: false
+-- main.cue --
+package main
+import "example.com/blah"
+
+-- _registry/example.com_v0.0.1/cue.mod/module.cue --
+module: "example.com@v0"
+deps: {
+	"foo.com/bar/hello@v0": v: "v0.2.3"
+	"bar.com@v0": v: "v0.5.0"
+}
+-- _registry/example.com_v0.0.1/blah/blah.cue --
+package blah
+import _ "foo.com/bar/hello/goodbye@v0"