fix: local_swift_package relative path resolution (#366)

This fixes the relative path resolution for local_swift_package when the
Package.swift is not in the root of the repository.

Closes #363

Author: luispadron

docs/repository_rules_overview.md

@@ -31,7 +31,7 @@ Used to build a local Swift package.
 | <a id="local_swift_package-bazel_package_name"></a>bazel_package_name |  The short name for the Swift package's Bazel repository.   | String | optional | <code>""</code> |
 | <a id="local_swift_package-dependencies_index"></a>dependencies_index |  A JSON file that contains a mapping of Swift products and Swift modules.   | <a href="https://bazel.build/concepts/labels">Label</a> | required |  |
 | <a id="local_swift_package-env"></a>env |  Environment variables that will be passed to the execution environments for this repository rule. (e.g. SPM version check, SPM dependency resolution, SPM package description generation)   | <a href="https://bazel.build/rules/lib/dict">Dictionary: String -> String</a> | optional | <code>{}</code> |
-| <a id="local_swift_package-path"></a>path |  The path to the local Swift package directory.   | String | required |  |
+| <a id="local_swift_package-path"></a>path |  The path to the local Swift package directory. This can be an absolute path or a relative path to the workspace root.   | String | required |  |
 | <a id="local_swift_package-repo_mapping"></a>repo_mapping |  A dictionary from local repository name to global repository name. This allows controls over workspace dependency resolution for dependencies of this repository.&lt;p&gt;For example, an entry <code>"@foo": "@bar"</code> declares that, for any time this repository depends on <code>@foo</code> (such as a dependency on <code>@foo//some:target</code>, it should actually resolve that dependency within globally-declared <code>@bar</code> (<code>@bar//some:target</code>).   | <a href="https://bazel.build/rules/lib/dict">Dictionary: String -> String</a> | required |  |
 
 

gazelle/internal/swift/repo_rule_from_bazel_repo.go

@@ -15,7 +15,7 @@ type commitProvider interface {
 
 // RepoRuleFromBazelRepo returns a repository rule declaration for a Swift Bazel repository.
 // The pkgDir is the path to the Swift package that is referencing this Bazel repository.
-func RepoRuleFromBazelRepo(bzlRepo *BazelRepo, diRel string, pkgDir string) (*rule.Rule, error) {
+func RepoRuleFromBazelRepo(bzlRepo *BazelRepo, diRel string, pkgDir string, repoDir string) (*rule.Rule, error) {
 	var r *rule.Rule
 	var err error
 	if bzlRepo.Pin != nil {
@@ -24,10 +24,19 @@ func RepoRuleFromBazelRepo(bzlRepo *BazelRepo, diRel string, pkgDir string) (*ru
 			return nil, err
 		}
 	} else {
-		relPath, err := filepath.Rel(pkgDir, bzlRepo.PkgInfo.Path)
+		// For local packages, the `path` attribute must be relative to the WORKSPACE file.
+		// However, since the Package.swift can exist anywhere in the repository, we need to
+		// resolve the relative path from the package directory and then get the relative path from the WORKSPACE.
+		relPathFromPkgDir, err := filepath.Rel(pkgDir, bzlRepo.PkgInfo.Path)
 		if err != nil {
 			return nil, err
 		}
+		absPathFromPkgDir := filepath.Join(pkgDir, relPathFromPkgDir)
+		relPath, err := filepath.Rel(repoDir, absPathFromPkgDir)
+		if err != nil {
+			return nil, err
+		}
+
 		r = repoRuleForLocalPackage(bzlRepo.Name, relPath)
 	}
 

gazelle/internal/swift/repo_rule_from_bazel_repo_test.go

@@ -13,7 +13,8 @@ import (
 )
 
 func TestRepoRuleFromBazelRepo(t *testing.T) {
-	pkgDir := "/path/to/package"
+	repoDir := "/path/to/repo"
+	pkgDir := "/path/to/repo"
 	diBasename := "swift_deps_index.json"
 
 	t.Run("with pin (source control dep)", func(t *testing.T) {
@@ -35,7 +36,7 @@ func TestRepoRuleFromBazelRepo(t *testing.T) {
 			Name: repoName,
 			Pin:  p,
 		}
-		actual, err := swift.RepoRuleFromBazelRepo(br, diBasename, pkgDir)
+		actual, err := swift.RepoRuleFromBazelRepo(br, diBasename, pkgDir, repoDir)
 		assert.NoError(t, err)
 
 		expected := rule.NewRule(swift.SwiftPkgRuleKind, repoName)
@@ -46,7 +47,8 @@ func TestRepoRuleFromBazelRepo(t *testing.T) {
 		assert.Equal(t, expected, actual)
 	})
 	t.Run("without pin (local Swift package)", func(t *testing.T) {
-		pkgDir := "/path/to/package"
+		repoDir := "/path/to/repo"
+		pkgDir := "/path/to/repo"
 		relLocalPkgDir := "third_party/cool_local_package"
 		localPkgDir := filepath.Join(pkgDir, relLocalPkgDir)
 		repoName := "swiftpkg_cool_local_package"
@@ -58,12 +60,34 @@ func TestRepoRuleFromBazelRepo(t *testing.T) {
 				Path: localPkgDir,
 			},
 		}
-		actual, err := swift.RepoRuleFromBazelRepo(br, diBasename, pkgDir)
+		actual, err := swift.RepoRuleFromBazelRepo(br, diBasename, pkgDir, repoDir)
 		assert.NoError(t, err)
 
 		expected := rule.NewRule(swift.LocalSwiftPkgRuleKind, repoName)
 		expected.SetAttr("path", relLocalPkgDir)
 		expected.SetAttr("dependencies_index", fmt.Sprintf("@//:%s", diBasename))
 		assert.Equal(t, expected, actual)
 	})
+	t.Run("without pin (local Swift package with relative path)", func(t *testing.T) {
+		repoDir := "/path/to/repo"
+		pkgDir := "/path/to/repo/third_party"
+		relLocalPkgDir := "../cool_local_package"
+		localPkgDir := filepath.Clean(filepath.Join(pkgDir, relLocalPkgDir))
+		repoName := "swiftpkg_cool_local_package"
+
+		br := &swift.BazelRepo{
+			Name: repoName,
+			PkgInfo: &swiftpkg.PackageInfo{
+				Name: "cool-local-package",
+				Path: localPkgDir,
+			},
+		}
+		actual, err := swift.RepoRuleFromBazelRepo(br, diBasename, pkgDir, repoDir)
+		assert.NoError(t, err)
+
+		expected := rule.NewRule(swift.LocalSwiftPkgRuleKind, repoName)
+		expected.SetAttr("path", "cool_local_package")
+		expected.SetAttr("dependencies_index", fmt.Sprintf("@//:%s", diBasename))
+		assert.Equal(t, expected, actual)
+	})
 }

gazelle/update_repos.go

@@ -150,7 +150,7 @@ func importReposFromPackageManifest(args language.ImportReposArgs) language.Impo
 	for _, bzlRepo := range bzlReposByIdentity {
 		repoUsage[bzlRepo.Name] = true
 		var err error
-		result.Gen[idx], err = swift.RepoRuleFromBazelRepo(bzlRepo, sc.DependencyIndexRel, pkgDir)
+		result.Gen[idx], err = swift.RepoRuleFromBazelRepo(bzlRepo, sc.DependencyIndexRel, pkgDir, c.RepoRoot)
 		if err != nil {
 			result.Error = err
 			return result

swiftpkg/internal/local_swift_package.bzl

@@ -64,7 +64,7 @@ def _local_swift_package_impl(repository_ctx):
 
 _PATH_ATTRS = {
     "path": attr.string(
-        doc = "The path to the local Swift package directory.",
+        doc = "The path to the local Swift package directory. This can be an absolute path or a relative path to the workspace root.",
         mandatory = True,
     ),
 }