cue/load: correctly handle the filesystem root as Config.ModuleRoot

mvdan · mvdan · commit d7a839b751e5 · 2025-10-29T13:53:02.000Z
Resolves the bug shown in the added test in the last commit. While here, make use of strings.CutPrefix to simplify the code a bit. Signed-off-by: Daniel Martí <mvdan@mvdan.cc> Change-Id: Ied6a5563f0d7ec3e23d3e29112d4a62c99332c9c Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1225185 TryBot-Result: CUEcueckoo <cueckoo@cuelang.org> Unity-Result: CUE porcuepine <cue.porcuepine@gmail.com> Reviewed-by: Roger Peppe <rogpeppe@gmail.com>
diff --git a/cue/load/import.go b/cue/load/import.go
@@ -388,12 +388,17 @@ func importPathFromAbsDir(c *Config, absDir string, origPath string) (importPath
 		return "", fmt.Errorf("cannot determine import path for %q (root undefined)", origPath)
 	}
 
-	dir := filepath.Clean(absDir)
-	if !strings.HasPrefix(dir, c.ModuleRoot) {
+	subdir, ok := strings.CutPrefix(filepath.Clean(absDir), c.ModuleRoot)
+	if !ok {
 		return "", fmt.Errorf("cannot determine import path for %q (dir outside of root)", origPath)
 	}
 
-	pkg := filepath.ToSlash(dir[len(c.ModuleRoot):])
+	pkg := filepath.ToSlash(subdir)
+	if pkg != "" && !strings.HasPrefix(pkg, "/") {
+		// [Config.ModuleRoot] was the root of the filesystem,
+		// and it had a trailing slash which got removed as a prefix; add it back.
+		pkg = "/" + pkg
+	}
 	switch {
 	case strings.HasPrefix(pkg, "/cue.mod/"):
 		pkg = pkg[len("/cue.mod/"):]
diff --git a/cue/load/import_test.go b/cue/load/import_test.go
@@ -139,8 +139,7 @@ language: version: "v0.11.0"
 
 	insts = Instances([]string{"./pkgdir"}, conf)
 	qt.Assert(t, qt.HasLen(insts, 1))
-	// qt.Assert(t, qt.IsNil(insts[0].Err))
-	qt.Assert(t, qt.ErrorMatches(insts[0].Err, "internal error: local import path .* resulted in non-internal package .*"))
-	// qt.Assert(t, qt.Equals(insts[0].Module, "mod.test@v0"))
-	// qt.Assert(t, qt.Equals(insts[0].ImportPath, "mod.test/pkgdir@v0:pkgname"))
+	qt.Assert(t, qt.IsNil(insts[0].Err))
+	qt.Assert(t, qt.Equals(insts[0].Module, "mod.test@v0"))
+	qt.Assert(t, qt.Equals(insts[0].ImportPath, "mod.test/pkgdir@v0:pkgname"))
 }
