Fix Bazel 8 compatibility in scip-java aspect

- Detect Bazel via MODULE.bazel in addition to WORKSPACE
- Tokenize compilation.javac_options via ctx.tokenize (depset of shell-quoted strings in Bazel 8)
- Replace struct.to_json() (removed in Bazel 8) with json.encode

Author: jupblb

scip-java/src/main/resources/scip-java/scip_java.bzl

@@ -97,21 +97,18 @@ def _scip_java(target, ctx):
         processorpath += [j.path for j in annotations.processor_classpath.to_list()]
         processors = annotations.processor_classnames
 
+    # In Bazel 8 compilation.javac_options is a depset of shell-quoted strings;
+    # ctx.tokenize splits each entry into proper individual flags.
+    raw_options = compilation.javac_options
+    if hasattr(raw_options, "to_list"):
+        raw_options = raw_options.to_list()
+
     launcher_javac_flags = []
     compiler_javac_flags = []
-
-    # In different versions of bazel javac options are either a nested set or a depset or a list...
-    javac_options = []
-    if hasattr(compilation, "javac_options_list"):
-        javac_options = compilation.javac_options_list
-    else:
-        javac_options = compilation.javac_options
-
-    for value in javac_options:
-        # NOTE(Anton): for some bizarre reason I see empty string starting the list of
-        # javac options - which then gets propagated into the JSON config, and ends up
-        # crashing the actual javac invokation.
-        if value != "":
+    for raw in raw_options:
+        for value in ctx.tokenize(raw):
+            if not value:
+                continue
             if value.startswith("-J"):
                 launcher_javac_flags.append(value)
             else:
@@ -134,7 +131,7 @@ def _scip_java(target, ctx):
     targetroot = ctx.actions.declare_directory(ctx.label.name + ".semanticdb")
     ctx.actions.write(
         output = build_config_path,
-        content = build_config.to_json(),
+        content = json.encode(build_config),
     )
 
     deps = [javac_action.inputs, annotations.processor_classpath]

scip-java/src/main/scala/com/sourcegraph/scip_java/buildtools/BazelBuildTool.scala

@@ -23,7 +23,9 @@ class BazelBuildTool(index: IndexCommand) extends BuildTool("Bazel", index) {
   override def isHidden: Boolean = true
 
   override def usedInCurrentDirectory(): Boolean = {
-    Files.isRegularFile(index.workingDirectory.resolve("WORKSPACE"))
+    val cwd = index.workingDirectory
+    List("MODULE.bazel", "WORKSPACE", "WORKSPACE.bazel")
+      .exists(f => Files.isRegularFile(cwd.resolve(f)))
   }
 
   private def targetSpecs =