feat: support location expansion in tar

lib/BUILD.bazel

@@ -104,10 +104,10 @@ bzl_library(
  name = "tar",
  srcs = ["tar.bzl"],
  deps = [
+ "//lib:expand_template",
  "//lib:utils",
  "//lib/private:tar",
  "@bazel_skylib//lib:types",
- "@bazel_skylib//rules:write_file",
  ],
 )
 

lib/tar.bzl

@@ -50,7 +50,7 @@ TODO:
 """
 
 load("@bazel_skylib//lib:types.bzl", "types")
-load("@bazel_skylib//rules:write_file.bzl", "write_file")
+load("//lib:expand_template.bzl", "expand_template")
 load("//lib:utils.bzl", "propagate_common_rule_attributes")
 load("//lib/private:tar.bzl", _tar = "tar", _tar_lib = "tar_lib")
 
@@ -64,7 +64,7 @@ tar_rule = _tar
 
 tar_lib = _tar_lib
 
-def tar(name, mtree = "auto", **kwargs):
+def tar(name, mtree = "auto", stamp = 0, **kwargs):
  """Wrapper macro around [`tar_rule`](#tar_rule).
 
  ### Options for mtree
@@ -94,6 +94,9 @@ def tar(name, mtree = "auto", **kwargs):
  Args:
  name: name of resulting `tar_rule`
  mtree: "auto", or an array of specification lines, or a label of a file that contains the lines.
+ Subject to [$(location)](https://bazel.build/reference/be/make-variables#predefined_label_variables)
+ and ["Make variable"](https://bazel.build/reference/be/make-variables) substitution.
+ stamp: should mtree attribute be stamped
  **kwargs: additional named parameters to pass to `tar_rule`
  """
  mtree_target = "_{}.mtree".format(name)
@@ -105,12 +108,18 @@ def tar(name, mtree = "auto", **kwargs):
  **propagate_common_rule_attributes(kwargs)
  )
  elif types.is_list(mtree):
- write_file(
+ expand_template(
  name = mtree_target,
  out = "{}.txt".format(mtree_target),
+ data = kwargs["srcs"],
  # Ensure there's a trailing newline, as bsdtar will ignore a last line without one
- content = mtree + [""],
- newline = "unix",
+ template = ["#mtree", "{content}", ""],
+ substitutions = {
+ # expand_template only expands strings in "substitions" dict. Here
+ # we expand mtree and then replace the template with expanded mtree.
+ "{content}": "\n".join(mtree),
+ },
+ stamp = stamp,
  **propagate_common_rule_attributes(kwargs)
  )
  else:

lib/tests/tar/BUILD.bazel

@@ -310,3 +310,21 @@ assert_archive_contains(
  "LICENSE",
  ],
 )
+
+# Case 10: Can reference generated files
+tar(
+ name = "tar_location_expansion",
+ srcs = ["@bazel_skylib//:LICENSE"],
+ out = "10.tar",
+ mtree = [
+ "a uid=0 gid=0 time=1672560000 mode=0755 type=file content=$(location @bazel_skylib//:LICENSE)",
+ ],
+)
+
+assert_tar_listing(
+ name = "test_tar_location_expansion",
+ actual = "tar_location_expansion",
+ expected = [
+ "-rwxr-xr-x 0 0 0 11358 Jan 1 2023 a",
+ ],
+)