starlark impl of java_common.pack_sources generates invalid srcjar when inputs come from external repository

[rbeasley]

Description of the bug:

Under Bazel 7, when feeding sources from an external repository to java_common.pack_sources, the sources are mapped to illegal paths beginning with ../. For example, if we pass @foo//:dummy.txt to pack_sources, we'll end up with a jar containing ../foo/dummy.txt.

Which category does this issue belong to?

Java Rules

What's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

## Set up main repo.
cat >pack_sources.bzl <<"EOF"
def _impl(ctx):
  java_common.pack_sources(
    ctx.actions,
    output_source_jar = ctx.outputs.out,
    sources = ctx.files.srcs,
    source_jars = [
      source_jar
      for dep in ctx.attr.deps
      for source_jar in dep[JavaInfo].source_jars
    ],
    java_toolchain = ctx.toolchains["@bazel_tools//tools/jdk:toolchain_type"].java,
  )

pack_sources = rule(
  _impl,
  attrs = {
    "deps": attr.label_list(providers=[JavaInfo]),
    "srcs": attr.label_list(allow_files = True),
  },
  outputs = {"out": "%{name}.srcjar"},
  toolchains = ["@bazel_tools//tools/jdk:toolchain_type"],
)
EOF

touch WORKSPACE

touch foo bar
cat >BUILD <<"EOF"
package(default_visibility=["//visibility:public"])
filegroup(name="srcs", srcs=["foo", "bar"])
EOF


## Set up subproject
mkdir -p subproject

cat >subproject/WORKSPACE <<"EOF"
local_repository(
  name = "superproject",
  path = "..",
)
EOF

cat >subproject/BUILD.bazel <<"EOF"
load("@superproject//:pack_sources.bzl", "pack_sources")

pack_sources(
  name = "packed",
  srcs = ["@superproject//:srcs"],
)

sh_test(
  name = "test_packed",
  srcs = ["test_packed.sh"],
  data = [":packed"],
)
EOF

cat >subproject/test_packed.sh <<"EOF"
zipinfo -1 $(find -L -name packed.srcjar) | grep -q ^foo
EOF
chmod +x subproject/test_packed.sh

## Build the srcjar and verify that foo is in the toplevel directory.
cd subproject

USE_BAZEL_VERSION=6.0.0 bazelisk test --noenable_bzlmod --java_runtime_version=remotejdk_11 :test_packed

USE_BAZEL_VERSION=7.0.0 bazelisk test --noenable_bzlmod --java_runtime_version=remotejdk_11 :test_packed

Which operating system are you running Bazel on?

Linux

What is the output of bazel info release?

release 7.0.0

If bazel info release returns development version or (@non-git), tell us how you built Bazel.

No response

What's the output of git remote get-url origin; git rev-parse master; git rev-parse HEAD ?

No response

Is this a regression? If yes, please try to identify the Bazel commit where the bug was introduced.

Yes. 6da7f21

Have you found anything relevant by searching the web?

No response

Any other information, logs, or outputs that you want to share?

I suspect that the Java and Starlark implementations aren't quite the same:

bazel/src/main/starlark/builtins_bzl/common/java/java_helper.bzl

Lines 295 to 299 in 2f899ef

	def _resource_mapper(file):
	return "%s:%s" % (
	file.path,
	semantics.get_default_resource_path(file.short_path, segment_extractor = _java_segments),
	)

bazel/src/main/java/com/google/devtools/build/lib/rules/java/SingleJarActionBuilder.java

Lines 139 to 146 in 2f899ef

	public void expandToCommandLine(Artifact resource, Consumer<String> args) {
	String execPath = resource.getExecPathString();
	String resourcePath =
	semantics.getDefaultJavaResourcePath(resource.getRootRelativePath()).getPathString();
	StringBuilder sb = new StringBuilder(execPath.length() + resourcePath.length() + 1);
	sb.append(execPath).append(":").append(resourcePath);
	args.accept(sb.toString());
	}

Compare resource.getRootRelativePath() to file.short_path.

IIUC, then based on the table at https://github.com/bazelbuild/rules_pkg/blob/main/pkg/mappings.bzl#L166-L177, instead of using file.short_path it should instead be paths.relativize(file.path, paths.normalize(paths.join(file.root.path, file.owner.workspace_root))).

[fmeum]

@bazel-io fork 7.0.1

[meteorcloudy]

/cc @hvadehra

[iancha1992]

A fix for this issue has been included in Bazel 7.0.1 RC2. Please test out the release candidate and report any issues as soon as possible. Thanks!

[iancha1992]

@bazel-io fork 7.1.0