Use jar from java runtime and not local_jdk (#720)

* Use jar from java runtime and not local_jdk
Work around and somewhat prepare for resolution of
bazelbuild/bazel#6955

* use stub template from an http_archive

* remove unused symbol

WORKSPACE

@@ -1,6 +1,16 @@
 workspace(name = "io_bazel_rules_scala")
 
+
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+#used to test what happens when classpath is too large
+#until https://github.com/bazelbuild/bazel/issues/6955 is resolved
+http_archive(
+    name = "java_stub_template",
+    sha256 = "1859a37dccaee8c56b98869bf1f22f6f5b909606aff74ddcfd59e9757a038dd5",
+    urls = ["https://github.com/bazelbuild/rules_scala/archive/8b8271e3ee5709e1340b19790d0b396a0ff3dd0f.tar.gz"],
+    strip_prefix = "rules_scala-8b8271e3ee5709e1340b19790d0b396a0ff3dd0f/java_stub_template",
+)
+
 load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")
 load("//scala:scala.bzl", "scala_repositories")
 

scala/private/rule_impls.bzl

@@ -550,16 +550,18 @@ def _path_is_absolute(path):
 def _runfiles_root(ctx):
     return "${TEST_SRCDIR}/%s" % ctx.workspace_name
 
-def _write_java_wrapper(ctx, args = "", wrapper_preamble = ""):
-    """This creates a wrapper that sets up the correct path
-         to stand in for the java command."""
-
+def _java_bin(ctx):
     java_path = str(ctx.attr._java_runtime[java_common.JavaRuntimeInfo].java_executable_runfiles_path)
     if _path_is_absolute(java_path):
         javabin = java_path
     else:
         runfiles_root = _runfiles_root(ctx)
         javabin = "%s/%s" % (runfiles_root, java_path)
+    return javabin
+
+def _write_java_wrapper(ctx, args = "", wrapper_preamble = ""):
+    """This creates a wrapper that sets up the correct path
+         to stand in for the java command."""
 
     exec_str = ""
     if wrapper_preamble == "":
@@ -576,13 +578,18 @@ JAVA_EXEC_TO_USE=${{REAL_EXTERNAL_JAVA_BIN:-$DEFAULT_JAVABIN}}
 """.format(
             preamble = wrapper_preamble,
             exec_str = exec_str,
-            javabin = javabin,
+            javabin = _java_bin(ctx),
             args = args,
         ),
         is_executable = True,
     )
     return wrapper
 
+def _jar_path_based_on_java_bin(ctx):
+    java_bin = _java_bin(ctx)
+    jar_path = java_bin.rpartition("/")[0] + "/jar"
+    return jar_path
+
 def _write_executable(ctx, rjars, main_class, jvm_flags, wrapper, use_jacoco):
     template = ctx.attr._java_stub_template.files.to_list()[0]
 
@@ -613,6 +620,7 @@ def _write_executable(ctx, rjars, main_class, jvm_flags, wrapper, use_jacoco):
             substitutions = {
                 "%classpath%": classpath,
                 "%javabin%": javabin,
+                "%jarbin%": _jar_path_based_on_java_bin(ctx),
                 "%jvm_flags%": jvm_flags,
                 "%needs_runfiles%": "",
                 "%runfiles_manifest_only%": "",
@@ -638,6 +646,7 @@ def _write_executable(ctx, rjars, main_class, jvm_flags, wrapper, use_jacoco):
                 "%classpath%": classpath,
                 "%java_start_class%": main_class,
                 "%javabin%": javabin,
+                "%jarbin%": _jar_path_based_on_java_bin(ctx),
                 "%jvm_flags%": jvm_flags,
                 "%needs_runfiles%": "",
                 "%runfiles_manifest_only%": "",

test/BUILD

@@ -434,6 +434,13 @@ scala_specs2_junit_test(
     "//test:test_scala_proto_server",
 ]]
 
+sh_test(
+    name = "test_binary_run_with_large_classpath",
+    srcs = ["test_binary_run_with_large_classpath.sh"],
+    args = ["$(location //test/src/main/scala/scalarules/test/large_classpath:largeClasspath)"],
+    data = ["//test/src/main/scala/scalarules/test/large_classpath:largeClasspath"],
+)
+
 # Make sure scala_binary works in genrule environment
 genrule(
     name = "ScalaBinaryInGenrule",

test/test_binary_run_with_large_classpath.sh

@@ -0,0 +1,6 @@
+#!/usr/bin/env bash
+
+echo "Executing: " $@
+#limiting the classpath to simulate a large classpath which is over the OS limit
+export CLASSPATH_LIMIT=10
+$@