Use llbuild's new content-exclusion-patterns node attribute to prevent it from descending into .build and .git directories (#5594) (#5599)

This requires the llbuild commit a1adaff2a405c3a74925e60356431050cb9a3a9d, but it does not cause problems if the llbuild being used doesn't yet support this property.  Instead it will be ignored.

This adds a dedicated unit test with a flat package.  We should consider whether any customized scratch directory should also be included in the list.  This is a little tricky since the exclusion patterns are applied to all subdirectory name, not just those at the top level.  In testing, it doesn't actually seem to be required, which seems a little surprising.  The fix in this commit is safe and good on its own, and we can consider adding customized scratch paths later once we've looked deeper into that issue.

rdar://93982172
(cherry picked from commit fb032ac)

Author: abertelrud

Fixtures/Miscellaneous/FlatPackage/MyExec.swift

@@ -0,0 +1,8 @@
+@main
+public struct MyExec {
+    public private(set) var text = "Hello, World!"
+
+    public static func main() {
+        print(MyExec().text)
+    }
+}

Fixtures/Miscellaneous/FlatPackage/MyTest.swift

@@ -0,0 +1,8 @@
+import XCTest
+@testable import MyExec
+
+final class MyTest: XCTestCase {
+    func testExample() throws {
+        XCTAssertEqual(MyExec().text, "Hello, World!")
+    }
+}

Fixtures/Miscellaneous/FlatPackage/Package.swift

@@ -0,0 +1,28 @@
+// swift-tools-version: 5.5
+import PackageDescription
+
+let execSrcFiles = ["MyExec.swift"]
+let testSrcFiles = ["MyTest.swift"]
+let variousFiles = ["README.md"]
+
+let package = Package(
+    name: "FlatPackage",
+    dependencies: [
+    ],
+    targets: [
+        .executableTarget(
+            name: "MyExec",
+            dependencies: [],
+            path: ".",
+            exclude: testSrcFiles + variousFiles,
+            sources: execSrcFiles
+        ),
+        .testTarget(
+            name: "MyTest",
+            dependencies: ["MyExec"],
+            path: ".",
+            exclude: execSrcFiles + variousFiles,
+            sources: testSrcFiles
+        ),
+    ]
+)

Fixtures/Miscellaneous/FlatPackage/README.md

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

Sources/LLBuildManifest/ManifestWriter.swift

@@ -48,9 +48,11 @@ public struct ManifestWriter {
         if !directoryStructureNodes.isEmpty {
             stream <<< "nodes:\n"
         }
+        let namesToExclude = [".git", ".build"]
         for node in directoryStructureNodes.sorted(by: { $0.name < $1.name }) {
             stream <<< "  " <<< Format.asJSON(node) <<< ":\n"
             stream <<< "    is-directory-structure: true\n"
+            stream <<< "    content-exclusion-patterns: " <<< Format.asJSON(namesToExclude) <<< "\n"
         }
 
         stream <<< "commands:\n"

Tests/BuildTests/LLBuildManifestTests.swift

@@ -48,6 +48,7 @@ final class LLBuildManifestTests: XCTestCase {
             nodes:
               "/some/dir/structure/":
                 is-directory-structure: true
+                content-exclusion-patterns: [".git",".build"]
             commands:
               "C.Foo":
                 tool: phony

Tests/FunctionalTests/MiscellaneousTests.swift

@@ -811,4 +811,20 @@ class MiscellaneousTestCase: XCTestCase {
             XCTAssertTrue(result.stderr.contains("Copying best.txt\n"), "build log is missing message about copying resource file")
         }
     }
+    
+    func testNoJSONOutputWithFlatPackageStructure() throws {
+        try fixture(name: "Miscellaneous/FlatPackage") { package in
+            // First build, make sure we got the `.build` directory where we expect it, and that there is no JSON output (by looking for known output).
+            let (stdout1, stderr1) = try SwiftPMProduct.SwiftBuild.execute([], packagePath: package)
+            XCTAssertDirectoryExists(package.appending(component: ".build"))
+            XCTAssertNoMatch(stdout1, .contains("command_arguments"))
+            XCTAssertNoMatch(stderr1, .contains("command_arguments"))
+            
+            // Now test, make sure we got the `.build` directory where we expect it, and that there is no JSON output (by looking for known output).
+            let (stdout2, stderr2) = try SwiftPMProduct.SwiftTest.execute([], packagePath: package)
+            XCTAssertDirectoryExists(package.appending(component: ".build"))
+            XCTAssertNoMatch(stdout2, .contains("command_arguments"))
+            XCTAssertNoMatch(stderr2, .contains("command_arguments"))
+        }
+    }
 }