Fix resource strip prefix (#1476)

Author: Bencodes

examples/nested_module_resources/BUILD.bazel

@@ -1,8 +1,77 @@
-load("@rules_kotlin//kotlin:jvm.bzl", "kt_jvm_binary")
+load("@rules_kotlin//kotlin:jvm.bzl", "kt_jvm_binary", "kt_jvm_library", "kt_jvm_test")
 
 kt_jvm_binary(
     name = "main",
-    srcs = glob(["*.kt"]),
+    srcs = ["Main.kt"],
     main_class = "MainKt",
     deps = ["@nested//:printer"],
 )
+
+# --- Resource libraries for integration testing ---
+
+# Case 1: Source resource WITH resource_strip_prefix
+kt_jvm_library(
+    name = "source_with_prefix",
+    resource_strip_prefix = "strip_prefix_resources",
+    resources = ["strip_prefix_resources/source_data.txt"],
+)
+
+# Case 2: Source resource WITHOUT resource_strip_prefix (no conventional prefix)
+kt_jvm_library(
+    name = "source_without_prefix",
+    resources = ["static_resources/source_no_prefix.txt"],
+)
+
+# Case 3: Generated resource WITH resource_strip_prefix
+genrule(
+    name = "gen_with_prefix",
+    outs = ["gen_prefix_out/generated_data.txt"],
+    cmd = "echo -n 'generated_with_prefix' > $@",
+)
+
+kt_jvm_library(
+    name = "generated_with_prefix",
+    resource_strip_prefix = "gen_prefix_out",
+    resources = [":gen_with_prefix"],
+)
+
+# Case 4: Generated resource WITHOUT resource_strip_prefix (core bug from #1469)
+genrule(
+    name = "gen_no_prefix",
+    outs = ["generated_no_prefix.txt"],
+    cmd = "echo -n 'generated_without_prefix' > $@",
+)
+
+kt_jvm_library(
+    name = "generated_without_prefix",
+    resources = [":gen_no_prefix"],
+)
+
+# Case 5: Generated resource under conventional prefix (src/main/resources/)
+genrule(
+    name = "gen_conventional",
+    outs = ["src/main/resources/conventional.txt"],
+    cmd = "echo -n 'generated_conventional' > $@",
+)
+
+kt_jvm_library(
+    name = "generated_conventional_prefix",
+    resources = [":gen_conventional"],
+)
+
+# --- Integration test: verifies resources are at correct classpath paths ---
+
+kt_jvm_test(
+    name = "resource_test",
+    srcs = ["ResourceTest.kt"],
+    main_class = "ResourceTest",
+    test_class = "ResourceTest",
+    deps = [
+        ":generated_conventional_prefix",
+        ":generated_with_prefix",
+        ":generated_without_prefix",
+        ":source_with_prefix",
+        ":source_without_prefix",
+        "@nested//:printer",
+    ],
+)

examples/nested_module_resources/ResourceTest.kt

@@ -0,0 +1,42 @@
+object ResourceTest {
+    private fun loadResource(path: String): String? =
+        Thread.currentThread().contextClassLoader.getResource(path)?.readText()?.trim()
+
+    private fun assertResource(path: String, expected: String, description: String) {
+        val content = loadResource(path)
+        check(content != null) { "FAIL [$description]: resource '$path' not found on classpath" }
+        check(content == expected) {
+            "FAIL [$description]: expected '$expected' but got '$content'"
+        }
+        println("PASS [$description]: '$path' = '$expected'")
+    }
+
+    @JvmStatic
+    fun main(args: Array<String>) {
+        assertResource(
+            "source_data.txt", "source_with_prefix",
+            "source resource with resource_strip_prefix",
+        )
+        assertResource(
+            "static_resources/source_no_prefix.txt", "source_without_prefix",
+            "source resource without resource_strip_prefix",
+        )
+        assertResource(
+            "generated_data.txt", "generated_with_prefix",
+            "generated resource with resource_strip_prefix",
+        )
+        assertResource(
+            "generated_no_prefix.txt", "generated_without_prefix",
+            "generated resource without resource_strip_prefix (issue #1469)",
+        )
+        assertResource(
+            "conventional.txt", "generated_conventional",
+            "generated resource under src/main/resources/ conventional prefix",
+        )
+        assertResource(
+            "resource.txt", "world",
+            "cross-module resource with resource_strip_prefix",
+        )
+        println("\nAll resource loading tests passed.")
+    }
+}

examples/nested_module_resources/static_resources/source_no_prefix.txt

@@ -0,0 +1 @@
+source_without_prefix

examples/nested_module_resources/strip_prefix_resources/source_data.txt

@@ -0,0 +1 @@
+source_with_prefix

kotlin/internal/jvm/compile.bzl

@@ -164,6 +164,16 @@ def _adjust_resources_path(path, resource_strip_prefix):
     else:
         return _adjust_resources_path_by_default_prefixes(path)
 
+def _resource_path_relative_to_root(resource):
+    if not resource.root.path:
+        return resource.path
+
+    root_prefix = resource.root.path + "/"
+    if resource.path.startswith(root_prefix):
+        return resource.path[len(root_prefix):]
+
+    return resource.path
+
 def _format_compile_plugin_options(o):
     """Format compiler option into id:value for cmd line."""
     return [
@@ -298,7 +308,8 @@ def _resourcejar_args_action(ctx, extra_resources = {}):
             strip_prefix = ctx.files.resources[0].root.path + "/" + strip_prefix
 
     for f in ctx.files.resources:
-        target_path = _adjust_resources_path(f.path, strip_prefix)
+        resource_path = f.path if strip_prefix else _resource_path_relative_to_root(f)
+        target_path = _adjust_resources_path(resource_path, strip_prefix)
         if target_path[0] == "/":
             target_path = target_path[1:]
         line = "{target_path}={f_path}\n".format(

src/test/starlark/internal/jvm/resource_strip_prefix_test.bzl

@@ -2,7 +2,7 @@ load("@bazel_skylib//lib:unittest.bzl", "analysistest", "asserts")
 load("@bazel_skylib//rules:write_file.bzl", "write_file")
 load("//kotlin:jvm.bzl", "kt_jvm_library")
 
-def _strip_resource_prefix_test_impl(ctx):
+def _resource_path_test_impl(ctx):
     env = analysistest.begin(ctx)
 
     actions = analysistest.target_actions(env)
@@ -17,16 +17,14 @@ def _strip_resource_prefix_test_impl(ctx):
 
     arguments = file_write_actions[0].content
 
-    pkg = ctx.attr.pkg
-
     # The only line should be of the form:
     # data.txt=<some prefix>/<pkg>/resourcez/data.txt
     lines = arguments.splitlines()
     asserts.equals(env, expected = 1, actual = len(lines))
     line_parts = lines[0].split("=", 1)
     asserts.equals(env, expected = 2, actual = len(line_parts))
     source_path = line_parts[1]
-    expected_suffix = pkg + "/" + ctx.attr.resource_strip_prefix + "/" + ctx.attr.resource_path
+    expected_suffix = ctx.attr.expected_source_suffix
     asserts.true(
         env,
         source_path.endswith(expected_suffix),
@@ -35,22 +33,27 @@ def _strip_resource_prefix_test_impl(ctx):
 
     destination_path = line_parts[0]
 
-    # The destination path should have the resource_strip_prefix removed
-    asserts.equals(env, expected = ctx.attr.resource_path, actual = destination_path, msg = "resource_strip_prefix was not applied correctly")
+    asserts.equals(
+        env,
+        expected = ctx.attr.expected_destination_path,
+        actual = destination_path,
+        msg = "resource path was not normalized correctly",
+    )
 
     return analysistest.end(env)
 
-strip_resource_prefix_test = analysistest.make(
-    _strip_resource_prefix_test_impl,
+resource_path_test = analysistest.make(
+    _resource_path_test_impl,
     attrs = {
-        "pkg": attr.string(),
-        "resource_path": attr.string(),
-        "resource_strip_prefix": attr.string(),
+        "expected_destination_path": attr.string(),
+        "expected_source_suffix": attr.string(),
     },
 )
 
 # Macro to setup the test.
 def _strip_resource_prefix_contents():
+    pkg = native.package_name()
+
     write_file(
         name = "file",
         out = "resourcez/resource.txt",
@@ -63,6 +66,18 @@ def _strip_resource_prefix_contents():
         tags = ["manual"],
     )
 
+    write_file(
+        name = "generated_default_file",
+        out = "generated/resource.txt",
+        tags = ["manual"],
+    )
+
+    write_file(
+        name = "generated_standard_resource",
+        out = "src/main/resources/generated_resource.txt",
+        tags = ["manual"],
+    )
+
     kt_jvm_library(
         name = "dynamically_created_file",
         srcs = ["source"],
@@ -86,6 +101,20 @@ def _strip_resource_prefix_contents():
         tags = ["manual"],
     )
 
+    kt_jvm_library(
+        name = "generated_default_package",
+        srcs = ["source"],
+        resources = ["generated_default_file"],
+        tags = ["manual"],
+    )
+
+    kt_jvm_library(
+        name = "generated_standard_package",
+        srcs = ["source"],
+        resources = ["generated_standard_resource"],
+        tags = ["manual"],
+    )
+
     package_name = native.package_name().split("/")[-1]
     native.filegroup(
         name = package_name,
@@ -100,40 +129,52 @@ def _strip_resource_prefix_contents():
         tags = ["manual"],
     )
 
-    strip_resource_prefix_test(
+    resource_path_test(
         name = "dynamically_created_file_test",
         target_under_test = ":dynamically_created_file",
         tags = ["manual"],
-        pkg = native.package_name(),
-        resource_strip_prefix = "resourcez",
-        resource_path = "resource.txt",
+        expected_destination_path = "resource.txt",
+        expected_source_suffix = pkg + "/resourcez/resource.txt",
     )
 
-    strip_resource_prefix_test(
+    resource_path_test(
         name = "static_file_test",
         target_under_test = ":static_file",
         tags = ["manual"],
-        pkg = native.package_name(),
-        resource_strip_prefix = "test_resources",
-        resource_path = "resource.txt",
+        expected_destination_path = "resource.txt",
+        expected_source_suffix = pkg + "/test_resources/resource.txt",
     )
 
-    strip_resource_prefix_test(
+    resource_path_test(
         name = "standard_package_test",
         target_under_test = ":standard_package",
         tags = ["manual"],
-        pkg = native.package_name(),
-        resource_strip_prefix = "src/main/resources",
-        resource_path = "resource.txt",
+        expected_destination_path = "resource.txt",
+        expected_source_suffix = pkg + "/src/main/resources/resource.txt",
     )
 
-    strip_resource_prefix_test(
+    resource_path_test(
+        name = "generated_default_package_test",
+        target_under_test = ":generated_default_package",
+        tags = ["manual"],
+        expected_destination_path = pkg + "/generated/resource.txt",
+        expected_source_suffix = pkg + "/generated/resource.txt",
+    )
+
+    resource_path_test(
+        name = "generated_standard_package_test",
+        target_under_test = ":generated_standard_package",
+        tags = ["manual"],
+        expected_destination_path = "generated_resource.txt",
+        expected_source_suffix = pkg + "/src/main/resources/generated_resource.txt",
+    )
+
+    resource_path_test(
         name = "same_as_package_name_test",
         target_under_test = ":same_as_package_name",
         tags = ["manual"],
-        pkg = native.package_name(),
-        resource_strip_prefix = "test_resources",
-        resource_path = "actual_file.txt",
+        expected_destination_path = "actual_file.txt",
+        expected_source_suffix = pkg + "/test_resources/actual_file.txt",
     )
 
 # Entry point from the BUILD file; macro for running each test case's macro and
@@ -146,6 +187,8 @@ def strip_resource_prefix_test_suite(name):
         name = name,
         tests = [
             ":dynamically_created_file_test",
+            ":generated_default_package_test",
+            ":generated_standard_package_test",
             ":static_file_test",
             ":standard_package_test",
             ":same_as_package_name_test",