MuntashirAkon/AppManager · error · IllegalArgumentException

Invalid format: package names do not match.

Error message

Invalid format: package names do not match.

What it means

RuleEntry.unflattenFromString parses an external flattened rule where each part may repeat the package name. When a subsequent token differs from the package name parsed earlier, it throws this IllegalArgumentException, because all package-name parts in an external rule line must be identical.

Solutions

  1. Make every package-name token in the flattened string identical
  2. Build the flattened string programmatically from entry.getPackageName() instead of by hand
  3. Check that you are not swapping the field order (name vs package)
  4. Catch IllegalArgumentException and report the malformed line

Example fix

// before
RuleEntry.unflattenFromString("com.a\tcom.b\tPERMISSION\t...", ...); // mismatch throws
// after
RuleEntry.unflattenFromString("com.a\tcom.a\tPERMISSION\t...", ...);
Defensive patterns

Strategy: validation

Validate before calling

String[] p = externalLine.split("\t");
if (p.length >= 2 && !p[0].equals(p[1]))
    throw new IllegalArgumentException("package names do not match");

Type guard

boolean hasConsistentPackageNames(String line) { String[] p = line.split("\t"); return p.length < 2 || p[0].equals(p[1]); }

Try / catch

try { RuleEntry.unflattenFromString(line, null); } catch (IllegalArgumentException e) { if (e.getMessage().contains("package names")) fixOrSkip(line); }

Prevention

When it happens

Trigger: Parsing a flattened string (external rule format, e.g. "pkgA\tpkgB\ttype\tname...") where the second package-name token does not equal the first, via RuleEntry.unflattenFromString or a subclass constructor.

Common situations: Hand-crafted external rule strings with a typo in the repeated package name, copy-paste mixing rules of two packages, or passing a process/component name where the package name is expected.

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

Related errors

AI-assisted analysis of MuntashirAkon/AppManager@0152f468fc (2026-09-12). Data as JSON: /api/errors/00618100ee6021b0. Report an issue: GitHub.

Appendix: source

Thrown at app/src/main/java/io/github/muntashirakon/AppManager/rules/struct/RuleEntry.java:67

    @NonNull
    public abstract String flattenToString(boolean isExternal);

    protected String addPackageWithTab(boolean isExternal) {
        return (isExternal ? packageName + "\t" : "");
    }

    @NonNull
    public static RuleEntry unflattenFromString(@Nullable String packageName, @NonNull String ruleLine,
                                                boolean isExternal) throws IllegalArgumentException {
        StringTokenizer tokenizer = new StringTokenizer(ruleLine, "\t");
        if (isExternal) {
            // External rules, the first part is the package name
            if (tokenizer.hasMoreElements()) {
                // Match package name
                String newPackageName = tokenizer.nextElement().toString();
                if (packageName == null) packageName = newPackageName;
                if (!packageName.equals(newPackageName)) {
                    throw new IllegalArgumentException("Invalid format: package names do not match.");
                }
            } else throw new IllegalArgumentException("Invalid format: packageName not found for external rule.");
        }
        if (packageName == null) {
            // packageName can't be empty
            throw new IllegalArgumentException("Package name cannot be empty.");
        }
        String name;
        RuleType type;
        if (tokenizer.hasMoreElements()) {
            name = tokenizer.nextElement().toString();
        } else throw new IllegalArgumentException("Invalid format: name not found");
        if (tokenizer.hasMoreElements()) {
            try {
                type = RuleType.valueOf(tokenizer.nextElement().toString());
            } catch (Exception e) {
                throw new IllegalArgumentException("Invalid format: Invalid type");
            }

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