refactor(bazel): Create an issue instead of throwing on no registry

Signed-off-by: Sebastian Schuberth <sebastian@doubleopen.org>

plugins/package-managers/bazel/src/main/kotlin/Bazel.kt

@@ -37,6 +37,7 @@ import org.ossreviewtoolkit.downloader.VersionControlSystem
 import org.ossreviewtoolkit.model.Hash
 import org.ossreviewtoolkit.model.HashAlgorithm
 import org.ossreviewtoolkit.model.Identifier
+import org.ossreviewtoolkit.model.Issue
 import org.ossreviewtoolkit.model.Package
 import org.ossreviewtoolkit.model.PackageLinkage
 import org.ossreviewtoolkit.model.PackageReference
@@ -49,6 +50,7 @@ import org.ossreviewtoolkit.model.VcsType
 import org.ossreviewtoolkit.model.collectDependencies
 import org.ossreviewtoolkit.model.config.AnalyzerConfiguration
 import org.ossreviewtoolkit.model.config.RepositoryConfiguration
+import org.ossreviewtoolkit.model.createAndLogIssue
 import org.ossreviewtoolkit.model.orEmpty
 import org.ossreviewtoolkit.utils.common.CommandLineTool
 import org.ossreviewtoolkit.utils.common.ProcessCapture
@@ -109,9 +111,15 @@ class Bazel(
         // If no lockfile is present, getDependencyGraph() runs "bazel mod graph", which creates a "MODULE.bazel.lock"
         // file as a side effect. That file contains the URL of the Bazel module registry that was used for dependency
         // resolution.
+        val issues = mutableListOf<Issue>()
         val registry = determineRegistry(parseLockfile(lockfile), projectDir)
 
-        val packages = getPackages(scopes, registry)
+        val packages = if (registry != null) {
+            getPackages(scopes, registry)
+        } else {
+            issues += createAndLogIssue(managerName, "Bazel registry URL cannot be determined from the lockfile.")
+            emptySet()
+        }
 
         return listOf(
             ProjectAnalyzerResult(
@@ -129,18 +137,19 @@ class Bazel(
                     homepageUrl = "",
                     scopeDependencies = scopes
                 ),
-                packages = packages
+                packages = packages,
+                issues = issues
             )
         )
     }
 
     /**
-     * This function determines the Bazel module registry to use based on the given [lockfile]: If this is a lockfile
-     * generated by Bazel version >= 7.2.0, a [CompositeBazelModuleRegistryService] based on the "registryFileHashes"
-     * will be returned. Else, either a [LocalBazelModuleRegistryService] or a [RemoteBazelModuleRegistryService] based
-     * on the "cmdRegistries" will be returned.
+     * Determine the Bazel module registry to use based on the Bazel version that generated the given [lockfile]. For
+     * Bazel version >= 7.2.0, a [CompositeBazelModuleRegistryService] based on the "registryFileHashes" is returned.
+     * For Bazel version < 7.2.0, either a [LocalBazelModuleRegistryService] or a [RemoteBazelModuleRegistryService]
+     * based on the "cmdRegistries" is returned. Return null if the registry cannot be determined.
      */
-    private fun determineRegistry(lockfile: Lockfile, projectDir: File): BazelModuleRegistryService {
+    private fun determineRegistry(lockfile: Lockfile, projectDir: File): BazelModuleRegistryService? {
         // Bazel version < 7.2.0.
         if (lockfile.flags != null) {
             return MultiBazelModuleRegistryService.create(lockfile.registryUrls(), projectDir)
@@ -151,9 +160,7 @@ class Bazel(
             return CompositeBazelModuleRegistryService.create(lockfile.registryFileHashes.keys, projectDir)
         }
 
-        val msg = "Bazel registry URL cannot be determined from the lockfile."
-        logger.error(msg)
-        error(msg)
+        return null
     }
 
     private fun getPackages(scopes: Set<Scope>, registry: BazelModuleRegistryService): Set<Package> {