## Official Guide { #official-guide }

Pydantic has an official [Migration Guide](https://docs.pydantic.dev/latest/migration/) from v1 to v2.

It also includes what has changed, how validations are now more correct and strict, possible caveats, etc.

You can read it to understand better what has changed.

## Tests { #tests }

Make sure you have [tests](../tutorial/testing.md) for your app and you run them on continuous integration (CI).

import com.google.caliper.Benchmark;
import org.jspecify.annotations.NullUnmarked;

/**
 * Simple benchmark: create, start, read. This does not currently report the most useful result
 * because it's ambiguous to what extent the stopwatch benchmark is being affected by GC.
 *
 * @author Kevin Bourrillion
 */
@NullUnmarked
public class StopwatchBenchmark {
  @Benchmark
  long stopwatch(int reps) {
    long total = 0;

* Why is this change done? What's the use case?
* For user-facing features, what will the API look like?
* What test cases should it have? What could go wrong?
* How will it roughly be implemented? We'll happily provide code pointers to save you time.

We may ask you to answer these questions directly in the GitHub issue or (for large changes) in a shared Google Doc.

available to TensorFlow is powerful enough that you should assume that the
TensorFlow process effectively executes arbitrary code.

The risk of loading untrusted checkpoints depends on the code or graph that you
are working with. When loading untrusted checkpoints, the values of the traced
variables from your model are also going to be untrusted. That means that if

<img src="/img/deployment/https/https03.drawio.svg">

The client already **trusts** the entity that generated that TLS certificate (in this case Let's Encrypt, but we'll see about that later), so it can **verify** that the certificate is valid.

If there's no `gzip` in the header, it will not try to decompress the body.

That way, the same route class can handle gzip compressed or uncompressed requests.

{* ../../docs_src/custom_request_and_route/tutorial001_an_py310.py hl[9:16] *}

### Create a custom `GzipRoute` class { #create-a-custom-gziproute-class }

Next, we create a custom subclass of `fastapi.routing.APIRoute` that will make use of the `GzipRequest`.

   - Include context in the summary: what changed, why, and any issue references.
   - Use `[WIP]` for in-progress PRs to avoid premature merging or choose GitHub draft PRs.

2. **Commits**:
   - Write clear messages: what changed and why (e.g., “Refactor S3 API handler to reduce latency so that requests process 20% faster”).

import org.apache.maven.api.annotations.Nonnull;

import static org.apache.maven.api.ExtensibleEnums.pathScope;

/**
 * Path scope.
 * A path scope is used to determine the kind of build or class path that will be built when resolving
 * dependencies using the {@link org.apache.maven.api.services.DependencyResolver} service.
 * <p>
 * This extensible enum has four defined values, {@link #MAIN_COMPILE}, {@link #MAIN_RUNTIME},

    try {
      ForwardingObjectTester.testForwardingObject(FailToForward.class);
    } catch (AssertionError | UnsupportedOperationException expected) {
      // UnsupportedOperationException is what we see on Android.
      return;
    }
    fail("Should have thrown");
  }

  @AndroidIncompatible // TODO(cpovirk): java.lang.IllegalAccessError: superclass not accessible
  public void testSuccessfulForwarding() {

  .
  .
  .
</plugins>

We need this form so that the model builder can make the first pass at merging. Full merging cannot be done because we don't know what the version of the plugin is yet that the user has requested. For plugins in the default lifecycle they are typically defined in the plugin management section of the parent POM. When the merging is complete we are going to have something that looks like the following:

<plugins>
  <plugin>