java_single_jar stamping

[benjaminp]

I was trying to replace a usage of java_binary's _deploy.jar with java_single_jar rule but was stymied by different stamping behavior.

$ cat BUILD
load("@rules_java//java:java_binary.bzl", "java_binary")
load("@rules_java//java:java_single_jar.bzl", "java_single_jar")

java_binary(
    name = "a",
    main_class = "none",
)

java_single_jar(
    name = "b",
    exclude_build_data = False,
)
$ bazel build --embed_label="foo" --stamp  //:a_deploy.jar //:b
$ unzip -c bazel-bin/a_deploy.jar  build-data.properties
Archive:  bazel-bin/a_deploy.jar
  inflating: build-data.properties   
build.target=@@//:a
main.class=none
build.label=foo
build.time=Thu Feb 26 20\:21\:01 2026 (1772137261)
build.timestamp=1772137261
build.timestamp.as.int=1772137261
$ unzip -c bazel-bin/b.jar  build-data.properties
Archive:  bazel-bin/b.jar
 extracting: build-data.properties   
build.target=bazel-out/k8-fastbuild/bin/b.jar

Is there some way to make b.jar's build-data.properties have the same content as a_deploy.jar's?

[hvadehra]

I think we just need to replicate

rules_java/java/common/rules/impl/java_binary_deploy_jar.bzl

Line 189 in f448104

args.add_all(build_info_files, before_each = "--build_info_file")

at

rules_java/java/common/rules/java_single_jar.bzl

Line 73 in f448104

args.add("--exclude_build_data")

@cushon Would there be any concerns with always including build info in java_single_jar if stamping is enabled?

[cushon]

I think we can make java_single_jar do whatever would be useful, but I am curious what the use-case is for stamped java_single_jar jars, and why using java_single_jar instead of java_binary is desired here?