Checkstyle works with generated config files (#227)

Fixes #226

Author: illicitonion

java/private/BUILD.bazel

@@ -13,7 +13,10 @@ bzl_library(
     name = "checkstyle",
     srcs = ["checkstyle.bzl"],
     visibility = ["//java:__subpackages__"],
-    deps = [":checkstyle_config"],
+    deps = [
+        ":checkstyle_config",
+        "@bazel_skylib//lib:paths",
+    ],
 )
 
 bzl_library(

java/private/checkstyle.bzl

@@ -1,5 +1,6 @@
 load(":checkstyle_config.bzl", "CheckStyleInfo")
 load("@apple_rules_lint//lint:defs.bzl", "LinterInfo")
+load("@bazel_skylib//lib:paths.bzl", "paths")
 
 """
 Checkstyle rule implementation
@@ -10,12 +11,15 @@ def _checkstyle_impl(ctx):
     config = info.config_file
     output_format = info.output_format
 
+    config_dir = paths.dirname(config.short_path)
+    maybe_cd_config_dir = ["cd {}".format(config_dir)] if config_dir else []
+
     script = "\n".join([
         "#!/usr/bin/env bash",
         "set -o pipefail",
         "set -e",
         "OLDPWD=$PWD",
-        "cd {config_dir}".format(config_dir = config.dirname),
+    ] + maybe_cd_config_dir + [
         "$OLDPWD/{lib} -f {output_format} -c {config} {srcs} |sed s:$OLDPWD/::g".format(
             lib = info.checkstyle.short_path,
             output_format = output_format,

java/test/com/github/bazel_contrib/contrib_rules_jvm/checkstyle/BUILD.bazel

@@ -12,6 +12,12 @@ checkstyle_config(
     data = ["suppressions.xml"],
 )
 
+checkstyle_config(
+    name = "copied_checkstyle_with_suppressions",
+    config_file = "copied_checkstyle_with_suppressions.xml",
+    data = ["suppressions.xml"],
+)
+
 checkstyle_test(
     name = "this_should_fail_missing_file",
     srcs = ["Sample.java"],
@@ -32,8 +38,21 @@ checkstyle_test(
     config = ":checkstyle_with_suppressions",
 )
 
+checkstyle_test(
+    name = "this_should_also_pass",
+    srcs = ["Sample.java"],
+    config = ":copied_checkstyle_with_suppressions",
+)
+
 java_library(
     name = "checkstyle",
     testonly = True,
     srcs = ["Sample.java"],
 )
+
+genrule(
+    name = "copy_config_file",
+    srcs = ["checkstyle_with_suppressions.xml"],
+    outs = ["copied_checkstyle_with_suppressions.xml"],
+    cmd = "cp $< $@",
+)