feat: parse output of swift package dump-package (#19)

- Add `.swiftformat` and `.swiftlint.yml` to the repo.
- Update `.gitignore` with Swift-specific entries.
- Add `MySwiftPackage` example.
- Implement `jsonutils` package to help with parsing Swift package dump
JSON.
- Implement `swiftpkg` package to parse the Swift package dump JSON.

.gitignore

@@ -1,2 +1,13 @@
 # Ignore Bazel symlinks
 bazel-*
+
+# Ignore Swift and Xcode stuff
+.DS_Store
+**/.build
+**/Packages
+**/*.xcodeproj
+**/xcuserdata/
+**/DerivedData/
+**/.swiftpm/config/registries.json
+**/.swiftpm/xcode/package.xcworkspace/contents.xcworkspacedata
+**/.netrc

.swiftformat

@@ -0,0 +1,11 @@
+# For information on the rules, see
+# https://github.com/nicklockwood/SwiftFormat/blob/master/Rules.md
+
+--allman false
+--indent 2
+--semicolons never 
+--stripunusedargs always
+--maxwidth 100
+--wraparguments before-first
+--wrapparameters before-first
+--wrapcollections before-first

.swiftlint.yml

@@ -0,0 +1,11 @@
+# List the rules by running "swiftlint rules"
+disabled_rules:
+  - trailing_comma
+excluded:
+  - .build
+identifier_name:
+  excluded:
+    - id
+    - db
+nesting:
+  type_level: 2

examples/MySwiftPackage/Package.resolved

@@ -0,0 +1,14 @@
+{
+  "pins" : [
+    {
+      "identity" : "swift-argument-parser",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-argument-parser",
+      "state" : {
+        "revision" : "fddd1c00396eed152c45a46bea9f47b98e59301d",
+        "version" : "1.2.0"
+      }
+    }
+  ],
+  "version" : 2
+}

examples/MySwiftPackage/Package.swift

@@ -0,0 +1,27 @@
+// swift-tools-version: 5.7
+// The swift-tools-version declares the minimum version of Swift required to build this package.
+
+import PackageDescription
+
+let package = Package(
+    name: "MySwiftPackage",
+    platforms: [.macOS(.v10_15)],
+    products: [
+        .executable(name: "printstuff", targets: ["MySwiftPackage"]),
+    ],
+    dependencies: [
+        .package(url: "https://github.com/apple/swift-argument-parser", from: "1.2.0"),
+    ],
+    targets: [
+        .executableTarget(
+            name: "MySwiftPackage",
+            dependencies: [
+                .product(name: "ArgumentParser", package: "swift-argument-parser"),
+            ]
+        ),
+        .testTarget(
+            name: "MySwiftPackageTests",
+            dependencies: ["MySwiftPackage"]
+        ),
+    ]
+)

examples/MySwiftPackage/README.md

@@ -0,0 +1,3 @@
+# MySwiftPackage
+
+A description of this package.

examples/MySwiftPackage/Sources/MySwiftPackage/MySwiftPackage.swift

@@ -0,0 +1,10 @@
+import ArgumentParser
+
+@main
+struct MySwiftPackage: AsyncParsableCommand {
+    public private(set) var text = "Hello, World!"
+
+    mutating func main() async throws {
+        print(MySwiftPackage().text)
+    }
+}

examples/MySwiftPackage/Tests/MySwiftPackageTests/MySwiftPackageTests.swift

@@ -0,0 +1,11 @@
+import XCTest
+@testable import MySwiftPackage
+
+final class MySwiftPackageTests: XCTestCase {
+    func testExample() throws {
+        // This is an example of a functional test case.
+        // Use XCTAssert and related functions to verify your tests produce the correct
+        // results.
+        XCTAssertEqual(MySwiftPackage().text, "Hello, World!")
+    }
+}

gazelle/BUILD.bazel

@@ -20,6 +20,7 @@ go_library(
     deps = [
         "//gazelle/internal/stringslices",
         "//gazelle/internal/swift",
+        "//gazelle/internal/swiftbin",
         "//gazelle/internal/wspace",
         "@bazel_gazelle//config:go_default_library",
         "@bazel_gazelle//label:go_default_library",

gazelle/config.go

@@ -7,13 +7,15 @@ import (
 	"github.com/bazelbuild/bazel-gazelle/config"
 	"github.com/bazelbuild/bazel-gazelle/rule"
 	"github.com/cgrindel/swift_bazel/gazelle/internal/swift"
+	"github.com/cgrindel/swift_bazel/gazelle/internal/swiftbin"
 	"github.com/cgrindel/swift_bazel/gazelle/internal/wspace"
 )
 
 const swiftConfigName = "swift"
 
 type swiftConfig struct {
-	moduleIndex *swift.ModuleIndex
+	moduleIndex  *swift.ModuleIndex
+	swiftBinPath string
 }
 
 func getSwiftConfig(c *config.Config) *swiftConfig {
@@ -29,8 +31,18 @@ func (*swiftLang) RegisterFlags(fs *flag.FlagSet, cmd string, c *config.Config)
 }
 
 func (sl *swiftLang) CheckFlags(fs *flag.FlagSet, c *config.Config) error {
+	var err error
 	sc := getSwiftConfig(c)
 
+	// TODO(chuck): Add flag so that the client can tell use which Swift to use.
+
+	// Find the Swift executable
+	sc.swiftBinPath, err = swiftbin.FindSwiftBinPath()
+	if err != nil {
+		return err
+	}
+
+	// Look for http_archive declarations with Swift declarations.
 	wkspFilePath := wspace.FindWORKSPACEFile(c.RepoRoot)
 	wkspFile, err := rule.LoadWorkspaceFile(wkspFilePath, "")
 	if err != nil {

gazelle/internal/jsonutils/BUILD.bazel

@@ -0,0 +1,28 @@
+load("@cgrindel_bazel_starlib//bzlformat:defs.bzl", "bzlformat_pkg")
+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "jsonutils",
+    srcs = [
+        "errors.go",
+        "json_map.go",
+        "json_slice.go",
+    ],
+    importpath = "github.com/cgrindel/swift_bazel/gazelle/internal/jsonutils",
+    visibility = ["//gazelle:__subpackages__"],
+)
+
+go_test(
+    name = "jsonutils_test",
+    srcs = [
+        "errors_test.go",
+        "json_map_test.go",
+        "json_slice_test.go",
+    ],
+    deps = [
+        ":jsonutils",
+        "@com_github_stretchr_testify//assert",
+    ],
+)
+
+bzlformat_pkg(name = "bzlformat")

gazelle/internal/jsonutils/errors.go

@@ -0,0 +1,123 @@
+package jsonutils
+
+import (
+	"fmt"
+)
+
+type mapKey struct {
+	Key string
+}
+
+type sliceIndex struct {
+	Index int
+}
+
+type unexpectedType struct {
+	ExpectedType string
+	ActualType   string
+}
+
+// MissingKeyError
+
+type MissingKeyError struct {
+	mapKey
+}
+
+func NewMissingKeyError(key string) *MissingKeyError {
+	return &MissingKeyError{
+		mapKey{Key: key},
+	}
+}
+
+func (e *MissingKeyError) Error() string {
+	return fmt.Sprintf("key '%v' not found", e.Key)
+}
+
+// KeyTypeError
+
+type KeyTypeError struct {
+	mapKey
+	unexpectedType
+}
+
+func NewKeyTypeError(key, expectedType string, actual any) *KeyTypeError {
+	return &KeyTypeError{
+		mapKey{Key: key},
+		unexpectedType{
+			ExpectedType: expectedType,
+			ActualType:   fmt.Sprintf("%T", actual),
+		},
+	}
+}
+
+func (e *KeyTypeError) Error() string {
+	return fmt.Sprintf(
+		"key '%s' expected to be type '%s', but was type '%s'",
+		e.Key, e.ExpectedType, e.ActualType)
+}
+
+// MarshalKeyError
+
+type KeyError struct {
+	Err error
+	mapKey
+}
+
+func NewKeyError(k string, err error) *KeyError {
+	mk := mapKey{Key: k}
+	return &KeyError{
+		Err:    err,
+		mapKey: mk,
+	}
+}
+
+func (e *KeyError) Error() string {
+	return fmt.Sprintf("error occurred processing '%v', %v", e.Key, e.Err)
+}
+
+func (e *KeyError) Unwrap() error {
+	return e.Err
+}
+
+// IndexTypeError
+
+type IndexTypeError struct {
+	sliceIndex
+	unexpectedType
+}
+
+func NewIndexTypeError(index int, expectedType string, actual any) *IndexTypeError {
+	return &IndexTypeError{
+		sliceIndex{Index: index},
+		unexpectedType{
+			ExpectedType: expectedType,
+			ActualType:   fmt.Sprintf("%T", actual),
+		},
+	}
+}
+
+func (e *IndexTypeError) Error() string {
+	return fmt.Sprintf(
+		"index %d expected to be type '%s', but was type '%s'",
+		e.Index, e.ExpectedType, e.ActualType)
+}
+
+// IndexOutOfBoundsError
+
+type IndexOutOfBoundsError struct {
+	sliceIndex
+	ActualLen int
+}
+
+func NewIndexOutOfBoundsError(idx, actualLen int) *IndexOutOfBoundsError {
+	return &IndexOutOfBoundsError{
+		sliceIndex: sliceIndex{Index: idx},
+		ActualLen:  actualLen,
+	}
+}
+
+func (e *IndexOutOfBoundsError) Error() string {
+	return fmt.Sprintf(
+		"index %d out of bounds for slice with length %d",
+		e.Index, e.ActualLen)
+}

gazelle/internal/jsonutils/errors_test.go

@@ -0,0 +1,45 @@
+package jsonutils_test
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/cgrindel/swift_bazel/gazelle/internal/jsonutils"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMissingKeyError(t *testing.T) {
+	key := "foo"
+	mke := jsonutils.NewMissingKeyError(key)
+	assert.Equal(t, key, mke.Key)
+	assert.Implements(t, (*error)(nil), mke)
+}
+
+func TestKeyTypeError(t *testing.T) {
+	key := "foo"
+	expectedType := "string"
+	kte := jsonutils.NewKeyTypeError(key, expectedType, 123)
+	assert.Equal(t, key, kte.Key)
+	assert.Equal(t, expectedType, kte.ExpectedType)
+	assert.Equal(t, "int", kte.ActualType)
+	assert.Implements(t, (*error)(nil), kte)
+}
+
+func TestKeyError(t *testing.T) {
+	key := "foo"
+	oerr := fmt.Errorf("original error")
+	ke := jsonutils.NewKeyError(key, oerr)
+	assert.Equal(t, ke.Key, key)
+	assert.Equal(t, ke.Err, oerr)
+	assert.Implements(t, (*error)(nil), ke)
+}
+
+func TestIndexTypeError(t *testing.T) {
+	index := 3
+	expectedType := "string"
+	ite := jsonutils.NewIndexTypeError(index, expectedType, 123)
+	assert.Equal(t, index, ite.Index)
+	assert.Equal(t, expectedType, ite.ExpectedType)
+	assert.Equal(t, "int", ite.ActualType)
+	assert.Implements(t, (*error)(nil), ite)
+}