Fix the Boringssl static dependency loop (#687)

Using netty-tcnative-boringssl-static as a dependency generates internal dependency loop

This is a test which demonstrates the problem and a solution which resolves the problem but may not be a good solution.

WORKSPACE

@@ -234,6 +234,8 @@ maven_install(
         # https://github.com/bazelbuild/rules_jvm_external/issues/371
         "com.fasterxml.jackson:jackson-bom:2.9.10",
         "org.junit:junit-bom:5.3.1",
+        # https://github.com/bazelbuild/rules_jvm_external/issues/686
+        "io.netty:netty-tcnative-boringssl-static:2.0.51.Final",
     ],
     generate_compat_repositories = True,
     maven_install_json = "//tests/custom_maven_install:regression_testing_install.json",

private/coursier_utilities.bzl

@@ -14,6 +14,9 @@
 # Coursier uses these types to determine what files it should resolve and fetch.
 # For example, some jars have the type "eclipse-plugin", and Coursier would not
 # download them if it's not asked to to resolve "eclipse-plugin".
+
+load ("//:specs.bzl", "parse")
+
 SUPPORTED_PACKAGING_TYPES = [
     "jar",
     "json",
@@ -27,6 +30,17 @@ SUPPORTED_PACKAGING_TYPES = [
     "scala-jar",
 ]
 
+# See https://github.com/bazelbuild/rules_jvm_external/issues/686
+# A single package uses classifier to distinguish the jar files (one per platform),
+# So we need to check these are not dependencies of each other.
+PLATFORM_CLASSIFIER = [
+    "linux-aarch_64",
+    "linux-x86_64",
+    "osx-aarch_64",
+    "osx-x86_64",
+    "windows-x86_64"
+]
+
 def strip_packaging_and_classifier(coord):
     # Strip some packaging and classifier values based on the following maven coordinate formats
     # groupId:artifactId:version
@@ -53,28 +67,19 @@ def strip_packaging_and_classifier_and_version(coord):
         return ":".join(coordinates)
     return ":".join(strip_packaging_and_classifier(coord).split(":")[:-1])
 
-# TODO: Should these methods be combined with _parse_maven_coordinate_string in specs.
+def match_group_and_artifact(source, target):
+    source_coord = parse.parse_maven_coordinate(source)
+    target_coord = parse.parse_maven_coordinate(target)
+    return source_coord["group"] == target_coord["group"] and source_coord["artifact"] == target_coord["artifact"]
+
 def get_packaging(coord):
-    # Get packaging from the following maven coordinate formats
-    # groupId:artifactId:version
-    # groupId:artifactId:packaging:version
-    # groupId:artifactId:packaging:classifier:version
-    coordinates = coord.split(":")
-    if len(coordinates) > 3:
-        return coordinates[2]
-    else:
-        return None
+    # Get packaging from the following maven coordinate
+    return parse.parse_maven_coordinate(coord).get("packaging", None)
 
 def get_classifier(coord):
-    # Get classifier from the following maven coordinate formats
-    # groupId:artifactId:version
-    # groupId:artifactId:packaging:version
-    # groupId:artifactId:packaging:classifier:version
-    coordinates = coord.split(":")
-    if len(coordinates) > 4:
-        return coordinates[3]
-    else:
-        return None
+    # Get classifier from the following maven coordinate
+    return parse.parse_maven_coordinate(coord).get("classifier", None)
+
 
 def escape(string):
     for char in [".", "-", ":", "/", "+"]:

private/dependency_tree_parser.bzl

@@ -17,7 +17,16 @@ This file contains parsing functions to turn a JSON-like dependency tree
 into target declarations (jvm_import) for the final @maven//:BUILD file.
 """
 
-load("//private:coursier_utilities.bzl", "escape", "get_classifier", "get_packaging", "strip_packaging_and_classifier", "strip_packaging_and_classifier_and_version")
+load(
+    "//private:coursier_utilities.bzl",
+    "escape",
+    "get_classifier",
+    "get_packaging",
+    "match_group_and_artifact",
+    "strip_packaging_and_classifier",
+    "strip_packaging_and_classifier_and_version",
+    "PLATFORM_CLASSIFIER"
+)
 
 JETIFY_INCLUDE_LIST_JETIFY_ALL = ["*"]
 
@@ -200,6 +209,13 @@ def _generate_imports(repository_ctx, dep_tree, explicit_artifacts, neverlink_ar
                 stripped_dep = strip_packaging_and_classifier_and_version(dep)
                 dep_target_label = escape(strip_packaging_and_classifier_and_version(dep))
 
+                # If we have matching artifacts with platform classifiers, skip adding this dependency.
+                # See https://github.com/bazelbuild/rules_jvm_external/issues/686
+                if match_group_and_artifact(artifact["coord"], dep) and \
+                    get_classifier(artifact["coord"]) in PLATFORM_CLASSIFIER and \
+                    get_classifier(dep) in PLATFORM_CLASSIFIER:
+                    continue
+
                 # Coursier returns cyclic dependencies sometimes. Handle it here.
                 # See https://github.com/bazelbuild/rules_jvm_external/issues/172
                 if dep_target_label != target_label: