FastAPI version 0.119.0 introduced partial support for Pydantic v1 from inside of Pydantic v2 (as `pydantic.v1`), to facilitate the migration to v2.

FastAPI 0.126.0 dropped support for Pydantic v1, while still supporting `pydantic.v1` for a little while.

/// warning

The Pydantic team stopped support for Pydantic v1 for the latest versions of Python, starting with **Python 3.14**.

          executor.execute(
              () -> {
                try {
                  startUp();
                  notifyStarted();
                  // If stopAsync() is called while starting we may be in the STOPPING state in
                  // which case we should skip right down to shutdown.
                  if (isRunning()) {
                    try {

    }

    private static String createMessage(List<ProjectBuildingResult> results) {
        if (results == null || results.isEmpty()) {
            return "Some problems were encountered while processing the POMs";
        }

        long totalProblems = 0;
        long errorProblems = 0;

        for (ProjectBuildingResult result : results) {

            this.visitor = visitor;
        }

        private void unwindTo(String element, TokenVisitor visitor) {
            if (elementStack.contains(element)) {
                while (!elementStack.getFirst().equals(element)) {
                    visitor.onEndHtmlElement(elementStack.removeFirst());
                }
                elementStack.removeFirst();

     * @return {@link List} $lt; {@link ArtifactVersion} >
     * @throws ArtifactMetadataRetrievalException
     *          in case of error while retrieving repository metadata from the repository.
     */
    List<ArtifactVersion> retrieveAvailableVersions(
            Artifact artifact, ArtifactRepository localRepository, List<ArtifactRepository> remoteRepositories)

    if (o == null) return false;
    E[] items = this.items;
    Monitor monitor = this.monitor;
    monitor.enter();
    try {
      int i = takeIndex;
      int k = 0;
      while (k++ < count) {
        if (o.equals(items[i])) return true;
        i = inc(i);
      }
      return false;
    } finally {
      monitor.leave();
    }
  }

  /**

 *       Future} is "completed" even if it is cancelled while its underlying work continues on a
 *       thread, an RPC, etc. The {@code Future} is also "completed" if it fails "early" -- for
 *       example, if the deadline expires on a {@code Future} returned from {@link
 *       Futures#withTimeout} while the {@code Future} it wraps continues its underlying work. So

                            return v != null ? v : configProps.getProperty(s);
                        });
                        configProps.putAll(props);
                    }
                } while (location != null);
            }
        }
        configProps.remove(INCLUDES_PROPERTY);
    }

    private static void trimValues(MavenProperties configProps) {

   * <p><b>Java 8+ users:</b> use {@link Long#parseUnsignedLong(String, int)} instead.
   *
   * @param string the string containing the unsigned {@code long} representation to be parsed.
   * @param radix the radix to use while parsing {@code string}
   * @throws NumberFormatException if the string does not contain a valid unsigned {@code long} with
   *     the given radix, or if {@code radix} is not between {@link Character#MIN_RADIX} and {@link

            if (n <= 0) {
                return (int) (fp - start > 0L ? fp - start : -1);
            }
            fp += n;
            len -= n;
            response.off += n;
        } while (len > 0 && n == r);

        return (int) (fp - start);
    }

    @Override
    public final void readFully(final byte b[]) throws SmbException {
        readFully(b, 0, b.length);
    }