test: add test coverage for docs rules

MODULE.bazel

@@ -12,6 +12,7 @@ module(
 
 bazel_dep(name = "bazel_skylib", version = "1.1.1")
 bazel_dep(name = "platforms", version = "0.0.4")
+bazel_dep(name = "stardoc", version = "0.5.0", repo_name = "io_bazel_stardoc")
 
 ext = use_extension("@aspect_bazel_lib//lib:extensions.bzl", "ext")
 use_repo(ext, "jq_toolchains")

e2e/bzlmod/BUILD.bazel

@@ -1,7 +1,29 @@
 load("@aspect_bazel_lib//lib:jq.bzl", "jq")
+
+# We don't use yq, so we can confirm that Bazel never fetches it.
+# You can manually verify this after testing this repo with
+# `ls $(bazel info output_base)/external | grep yq`
+# You'll see a aspect_bazel_lib.ext.yq_toolchains repo, but no downloaded yq binary.
+load("@aspect_bazel_lib//lib:docs.bzl", "stardoc_with_diff_test")
+load("@bazel_skylib//:bzl_library.bzl", "bzl_library")
 load("@bazel_skylib//rules:diff_test.bzl", "diff_test")
 
-# No sources produces null (equivalent to --null-input)
+bzl_library(
+    name = "defs",
+    srcs = ["defs.bzl"],
+)
+
+# Validate that stardoc dependency works.
+# Note, stardoc is generally broken under bzlmod, see
+# https://github.com/bazelbuild/stardoc/issues/117
+# This happens to work because we don't reference any external repos
+# from defs.bzl.
+stardoc_with_diff_test(
+    name = "docs",
+    bzl_library_target = "//:defs",
+)
+
+# Validate that JQ works and resolves its toolchain
 jq(
     name = "case_no_sources",
     srcs = [],

e2e/bzlmod/WORKSPACE

@@ -0,0 +1,2 @@
+# Marker file that this folder is the root of a Bazel workspace.
+# See MODULE.bazel for dependencies and setup.

e2e/bzlmod/defs.bzl

@@ -0,0 +1 @@
+# no rules

e2e/bzlmod/docs.md

@@ -0,0 +1 @@
+<!-- Generated with Stardoc: http://skydoc.bazel.build -->

lib/private/docs.bzl

@@ -6,25 +6,17 @@ load("//lib:write_source_files.bzl", "write_source_files")
 def stardoc_with_diff_test(
         name,
         bzl_library_target,
-        aspect_template = "@io_bazel_stardoc//stardoc:templates/markdown_tables/aspect.vm",
-        func_template = "@io_bazel_stardoc//stardoc:templates/markdown_tables/func.vm",
-        header_template = "@io_bazel_stardoc//stardoc:templates/markdown_tables/header.vm",
-        provider_template = "@io_bazel_stardoc//stardoc:templates/markdown_tables/provider.vm",
-        rule_template = "@io_bazel_stardoc//stardoc:templates/markdown_tables/rule.vm",
-        suggested_update_target = "//docs:update"):
+        suggested_update_target = "//docs:update",
+        **kwargs):
     """Creates a stardoc target, diff test, and an executable to rule to write the generated doc to the source tree and test that it's up to date.
 
     This is helpful for minimizing boilerplate in repos wih lots of stardoc targets.
 
     Args:
         name: the name of the stardoc file to be written to the current source directory (.md will be appended to the name). Call bazel run on this target to update the file.
         bzl_library_target: the label of the `bzl_library` target to generate documentation for
-        aspect_template: the label or path to the Velocity aspect template to use with stardoc
-        func_template: the label or path to the Velocity function/macro template to use with stardoc
-        header_template: the label or path to the Velocity header template to use with stardoc
-        provider_template: the label or path to the Velocity provider template to use with stardoc
-        rule_template: the label or path to the Velocity rule template to use with stardoc
         suggested_update_target: the target suggested to be run when a doc is out of date (should be the label for [update_docs](#update_docs))
+        **kwargs: additional attributes passed to the stardoc() rule, such as for overriding the templates
     """
 
     stardoc_label = name + "-docgen"
@@ -36,12 +28,8 @@ def stardoc_with_diff_test(
         out = name + "-docgen.md",
         input = bzl_library_target + ".bzl",
         deps = [bzl_library_target],
-        aspect_template = aspect_template,
-        func_template = func_template,
-        header_template = header_template,
-        provider_template = provider_template,
-        rule_template = rule_template,
         tags = ["package:" + native.package_name()],  # Tag the package name which will help us reconstruct the write_source_files label in update_docs
+        **kwargs
     )
 
     write_source_files(