Switch API to use find rather than add.

vars/findVersionFromNexusRepo.groovy

@@ -26,6 +26,9 @@ Map call(Map config = [:], Map queryParams = [:]) {
     Map runConfig = defaults + config
     Map query = queryParamsDefaults + queryParams
 
+    def version
+    def response
+
     nexusURL = runConfig.nexusBase + '/' + runConfig.searchAPI
     nexusSearch = buildUrlWithQueryParams(nexusURL, query)
  
@@ -33,24 +36,32 @@ Map call(Map config = [:], Map queryParams = [:]) {
         contentType: 'APPLICATION_JSON',
         url: nexusSearch,
         wrapAsMultipart: false
+        
+
     body = response.content
     assets = readJSON text: body
+    if (assets.items && !assets.items.isEmpty()) {
         latest = assets.items.last()
-    version = latest.version ?: (latest.name =~ /.*-([0-9\.]+)-([0-9]+)\..*/)[0][1]
-    build = latest.version ?: (latest.name =~ /.*-([0-9\.]+)-([0-9]+)\..*/)[0][2]
-
-    if (version == null) {
-        // Call the error method and pass a string indicating version was null and name is not parseable
-        error('Version was null and name is not parseable')
+        /* We have to use instanceof here. The value SHOULD be null, but it comes back
+            as class rather than null. This is probably a bug in the Pipeline Utilities
+            plugin. */
+        /* groovylint-disable-next-line Instanceof */
+        if (latest.version instanceof net.sf.json.JSONNull && latest.name) {
+            echo "Search result version field was null, looking in name field for a version"
+            def match = (latest.name =~ /(?<=-)([0-9\.]{1,3})(?:-|\.)[^-\.]+/)
+            if (!match) {
+                echo "Match: ${match}"
+                error("Regular expression match failed for latest.name: ${latest.name}")
             }
-
-    if (build == null) {
-        unstable("Build number could not be found in latest asset match (${latest.name})")
+            version = match[0][1]
+        } else if (latest.version) {
+            version = latest.version
         }
-    build = build ?: env.BUILD_NUMBER
-    runConfig.version = version
-    runConfig.build = build
-    return runConfig
+    } else {
+        version = '0.0.1'
+        unstable('No matching assets found, assuming this is the first version')
+    }
+    return version
 }
 
 /* groovylint-disable-next-line MethodParameterTypeRequired, NoDef */