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# Lucene upgrade steps

## Read

https://lucene.apache.org/core/9_4_0/MIGRATE.html

## Start

Create a new branch locally e.g. `git checkout -b lucene940 -t origin/main` for upgrading to Lucene 9.4.0 version.

## Build

### `versions.props` update

```
- org.apache.lucene:*=9.3.0
+ org.apache.lucene:*=9.4.0
```

### `versions.lock` update

```
gradlew --write-locks
```

### `solr/licenses` update

```
gradlew updateLicenses

git add solr/licenses
```

## Code

```
gradlew compileJava
```

* adjust for signature changes e.g.
  * `int` to `long` type change
  * additional or removed constructor arguments
  * additional abstract base class or interface methods
  * inner classes becoming outer classes
* codec changes (if any)
  * conceptually `s/org.apache.lucene.codecs.lucene9x.Lucene9x/org.apache.lucene.codecs.lucene94.Lucene94`

## Test

```
gradlew compileTestJava
```

```
gradlew precommit
```

```
gradlew test
```

## Finish

Push the local branch to github (fork) and open a pull request.

## Looking for something else?

Thanks for reading these upgrade steps! But perhaps you were looking for information on trying out prerelease Lucene changes or joint local Solr and Lucene development? If so then please see the 'Update Lucene prerelease' and 'Lucene local dependency substitution' sections in the [help/dependencies.txt](../help/dependencies.txt) documentation.