Make version guessing more robust, and error messages more informative. (#38)

Author: LexManos

.gitignore

@@ -1,19 +1,29 @@
+#eclipse
+**/bin
+**/.settings
+**/.classpath
+*.project
 
-/.gradle/
-/build/
-/.idea/
+#idea
+/.idea
+/*/out
+/classes
+*.iml
+
+#gradle
+/build
+/.gradle
+/*/build
+/*/.gradle
+
+#misc
 /out/
 /forge-1.16.5-36.1.16.jar
 /tmp/
-/bin/
-/.settings/
-/.classpath
-/.project
 /repo/
 /Bookshelf-1.16.4-9.0.7-TAMPERED.jar
 /Bookshelf-1.16.4-9.0.7-UNTAMPERED.jar
 /inventorysorter-1.16.1-18.0.0.jar
 /modlauncher-9.0.1.jar
 /test.jar
-/sjh-jmh/build/
 *.jfr

src/main/java/cpw/mods/jarhandling/JarMetadata.java

@@ -65,12 +65,13 @@ static SimpleJarMetadata fromFileName(final Path path, final Set<String> pkgs, f
                     var ver = versionMaybe.getFileName().toString();
                     var mat = MODULE_VERSION.matcher(ver);
                     if (mat.find()) {
-                        ver = ModuleDescriptor.Version.parse(ver.substring(mat.start())).toString();
+                        var potential = ver.substring(mat.start());
+                        ver = safeParseVersion(potential, path.getFileName().toString());
                         return new SimpleJarMetadata(cleanModuleName(name), ver, pkgs, providers);
                     } else {
                         return new SimpleJarMetadata(cleanModuleName(name), null, pkgs, providers);
                     }
-                }   
+                }
             }
         }
 
@@ -83,14 +84,34 @@ static SimpleJarMetadata fromFileName(final Path path, final Set<String> pkgs, f
 
         var mat = DASH_VERSION.matcher(fn);
         if (mat.find()) {
-            var ver = ModuleDescriptor.Version.parse(fn.substring(mat.start() + 1)).toString();
+            var potential = fn.substring(mat.start() + 1);
+            var ver = safeParseVersion(potential, path.getFileName().toString());
             var name = mat.replaceAll("");
             return new SimpleJarMetadata(cleanModuleName(name), ver, pkgs, providers);
         } else {
             return new SimpleJarMetadata(cleanModuleName(fn), null, pkgs, providers);
         }
     }
 
+    private static String safeParseVersion(String ver, String filename) {
+        try {
+            var len = ver.length();
+            if (len == 0)
+                throw new IllegalArgumentException("Error parsing version info from " + filename + ": Empty Version String");
+
+            var last = ver.charAt(len - 1);
+            if (last == '.' || last == '+' || last == '-') { //Attempt to filter out the common wrong file names.
+                if (len == 1)
+                    throw new IllegalArgumentException("Error parsing version info from " + filename + ": Invalid version \"" + ver + "\"");
+                ver = ver.substring(0, len - 1);
+            }
+
+            return ModuleDescriptor.Version.parse(ver).toString();
+        } catch (IllegalArgumentException e) {
+            throw new IllegalArgumentException("Error parsing version info from " + filename + " (" + ver + "): " + e.getMessage(), e);
+        }
+    }
+
     private static String cleanModuleName(String mn) {
 
         // replace non-alphanumeric