didi/DoKit · error · IllegalArgumentException

Multiple wildcards present in rule expression " + ruleExpres

Error message

Multiple wildcards present in rule expression " + ruleExpression

What it means

Thrown by MimeMatcher.MimeMatcherRule's constructor when a rule expression contains more than one '*' wildcard. Only a single trailing wildcard (e.g. "image/*") is supported: the constructor strips one trailing '*' into a prefix match, then rejects any remaining '*' in the prefix because prefix matching cannot express interior wildcards.

Source

Thrown at Android/dokit/src/main/java/com/didichuxing/doraemonkit/kit/network/core/MimeMatcher.java:53

    return null;
  }

  @SuppressLint("BadMethodUse-java.lang.String.length")
  private class MimeMatcherRule {
    private final boolean mHasWildcard;
    private final String mMatchPrefix;
    private final T mResultIfMatched;

    public MimeMatcherRule(String ruleExpression, T resultIfMatched) {
      if (ruleExpression.endsWith("*")) {
        mHasWildcard = true;
        mMatchPrefix = ruleExpression.substring(0, ruleExpression.length() - 1);
      } else {
        mHasWildcard = false;
        mMatchPrefix = ruleExpression;
      }
      if (mMatchPrefix.contains("*")) {
        throw new IllegalArgumentException("Multiple wildcards present in rule expression " +
            ruleExpression);
      }
      mResultIfMatched = resultIfMatched;
    }

    public boolean match(String mimeType) {
      if (!mimeType.startsWith(mMatchPrefix)) {
        return false;
      }
      return (mHasWildcard || mimeType.length() == mMatchPrefix.length());
    }

    public T getResultIfMatched() {
      return mResultIfMatched;
    }
  }
}

View on GitHub (pinned to 626827cddb)

Solutions

Use a single trailing wildcard only: "image/*" instead of "*/*" — for match-everything use an empty prefix with trailing '*', i.e. "*"
Express interior/suffix patterns as multiple explicit rules or match on substring in your own code instead of MimeMatcher
Validate the expression at configuration load time and fail fast with a clear config error

Example fix

// before
matcher.addRule("*/*", MATCH_ALL); // second '*' inside prefix -> throws

// after
matcher.addRule("*", MATCH_ALL); // single trailing wildcard, matches everything

Defensive patterns

Strategy: validation

Validate before calling

static boolean isValidMimeRule(String expr) {
  if (expr == null) return false;
  String prefix = expr.endsWith("*") ? expr.substring(0, expr.length() - 1) : expr;
  return prefix.indexOf('*') == -1;
}

Prevention

Use only a single trailing wildcard ('image/*', '*')
Do not copy Accept-header patterns like '*/*' or '*+json' into MimeMatcher rules

When it happens

Trigger: Constructing a rule with expression "*/*", "image/*;q=*", "application/*+json*", or any string where '*' appears anywhere except the final character. The check runs at rule-creation time, before any match() call.

Common situations: Registering MIME rules for the network/image inspector with patterns borrowed from Accept headers (where "*/*" is idiomatic) or glob habits from other libraries; trying to express suffix patterns like "*+json".

Related errors

AI-assisted analysis of didi/DoKit@626827cddb (2026-08-14). Data as JSON: /api/errors/61699324c19d9a6b. Report an issue: GitHub.