redis/jedis · error · IllegalStateException

Attribute for this field is already set.

Error message

Attribute for this field is already set.

What it means

A FieldName instance may only be given one attribute/alias. Calling as() a second time throws IllegalStateException because the attribute was already set, preventing silent overwrite of an earlier alias.

Solutions

1. Create a new FieldName for each distinct attribute mapping
2. Call as() exactly once per FieldName instance
3. If reuse is intended, clone/reset: build FieldName.from( existing ) fresh before calling as()

Example fix

// before
FieldName f = new FieldName("title").as("t");
f.as("title_alias"); // throws
// after
FieldName f1 = new FieldName("title").as("t");
FieldName f2 = new FieldName("title").as("title_alias");

// create a fresh instance each time instead of guarding state
FieldName renamed = FieldName.of(base.getName()).as(attribute);

When it happens

Trigger: Calling field.as("a").as("b") on the same FieldName; reusing a cached FieldName object across multiple schema definitions without creating a new instance.

Common situations: Reusing shared/static FieldName instances in index-definition builders; loops that accumulate aliases on one object; copy-paste schema code applying as() twice.

Understand the failure class

Background: "Invalid state transition" errors: "status must be X, actually Y", "already rejected/charging/uninstalled", "cannot ... while running" — what they mean when a library rejects your call — this error's family across 31 libraries.

Related errors

• Setting null as field attribute is not allowed.
• A null argument cannot be sent to Redis.
• Unrecognized header
• DIALECT=0 cannot be set.
• HashImport ' ' has been discarded

AI-assisted analysis of redis/jedis@6dac31d4c2 (2026-09-08). Data as JSON: /api/errors/9aa367039650a101. Report an issue: GitHub.

Appendix: source

Thrown at src/main/java/redis/clients/jedis/search/FieldName.java:27

  private final String name;
  private String attribute;

  public FieldName(String name) {
    this.name = name;
  }

  public FieldName(String name, String attribute) {
    this.name = name;
    this.attribute = attribute;
  }

  public FieldName as(String attribute) {
    if (attribute == null) {
      throw new IllegalArgumentException("Setting null as field attribute is not allowed.");
    }
    if (this.attribute != null) {
      throw new IllegalStateException("Attribute for this field is already set.");
    }
    this.attribute = attribute;
    return this;
  }

  public final String getName() {
    return name;
  }

  public final String getAttribute() {
    return attribute;
  }

  public int addCommandArguments(List<Object> args) {
    args.add(name);
    if (attribute == null) {
      return 1;
    }

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