Method onStartTagClose

xml/_parser.ts:304–484

(selfClosing: boolean)

  }

  onStartTagClose(selfClosing: boolean): void {
    if (this.#hasPendingElement) {
      // XML 1.0 §2.8: Only one root element is allowed
      if (this.#rootClosed) {
        throw new XmlSyntaxError(
          "Only one root element is allowed (XML 1.0 §2.8)",
          {
            line: this.#pendingLine,
            column: this.#pendingColumn,
            offset: this.#pendingOffset,
          },
        );
      }

      // Validate element prefix is bound (if it has one) and resolve URI
      let elementUri: string | undefined;
      if (this.#pendingColonIndex !== -1) {
        const prefix = this.#pendingName.slice(0, this.#pendingColonIndex);
        // xml prefix is always implicitly bound, xmlns prefix is handled separately
        if (prefix !== "xml" && prefix !== "xmlns") {
          elementUri = this.#nsBindings?.get(prefix);
          if (elementUri === undefined) {
            throw new XmlSyntaxError(
              `Unbound namespace prefix '${prefix}' in element <${this.#pendingName}>`,
              {
                line: this.#pendingLine,
                column: this.#pendingColumn,
                offset: this.#pendingOffset,
              },
            );
          }
        } else if (prefix === "xml") {
          elementUri = XML_NAMESPACE;
        }
      }

      // Validate attribute prefixes are bound, resolve URIs, and check for duplicate expanded names
      // Optimized: only do expensive expansion check when same local name appears with different prefixes
      const attrCount = this.#attrIterator.count;
      let localNameToPrefixes: Map<string, string[]> | null = null;

      for (let i = 0; i < attrCount; i++) {
        const colonIdx = this.#attrIterator.getColonIndex(i);
        if (colonIdx !== -1) {
          const attrName = this.#attrIterator.getName(i);
          const prefix = attrName.slice(0, colonIdx);
          // Skip xmlns: attributes (they declare, not use, prefixes)
          if (prefix === "xmlns") {
            // xmlns: attributes don't have namespace URIs (they ARE the declarations)
            continue;
          }
          // xml prefix is always implicitly bound
          if (prefix === "xml") {
            this.#attrIterator._setUri(i, XML_NAMESPACE);
            continue;
          }
          const attrUri = this.#nsBindings?.get(prefix);
          if (attrUri === undefined) {