Revert "LUCENE-9433: Remove Ant support from trunk"

This reverts commit 37cd17d

.github/PULL_REQUEST_TEMPLATE.md

@@ -38,6 +38,6 @@ Please review the following and check all that apply:
 - [ ] I have created a Jira issue and added the issue ID to my pull request title.
 - [ ] I have given Solr maintainers [access](https://help.github.com/en/articles/allowing-changes-to-a-pull-request-branch-created-from-a-fork) to contribute to my PR branch. (optional but recommended)
 - [ ] I have developed this patch against the `master` branch.
-- [ ] I have run `./gradlew check`.
+- [ ] I have run `ant precommit` and the appropriate test suite.
 - [ ] I have added tests for my changes.
 - [ ] I have added documentation for the [Ref Guide](https://github.com/apache/lucene-solr/tree/master/solr/solr-ref-guide) (for Solr changes only).

README.md

@@ -20,7 +20,7 @@
 Apache Lucene is a high-performance, full featured text search engine library
 written in Java.
 
-Apache Solr is an enterprise search platform written in Java and using Apache Lucene.
+Apache Solr is an enterprise search platform written using Apache Lucene.
 Major features include full-text search, index replication and sharding, and
 result faceting and highlighting.
 
@@ -40,30 +40,48 @@ comprehensive documentation, visit:
 
 (You do not need to do this if you downloaded a pre-built package)
 
+### Building with Ant
+
+Lucene and Solr are built using [Apache Ant](http://ant.apache.org/).  To build
+Lucene and Solr, run:
+
+`ant compile`
+
+If you see an error about Ivy missing while invoking Ant (e.g., `.ant/lib does
+not exist`), run `ant ivy-bootstrap` and retry.
+
+Sometimes you may face issues with Ivy (e.g., an incompletely downloaded artifact).
+Cleaning up the Ivy cache and retrying is a workaround for most of such issues: 
+
+`rm -rf ~/.ivy2/cache`
+
+The Solr server can then be packaged and prepared for startup by running the
+following command from the `solr/` directory:
+
+`ant server`
 
 ### Building with Gradle
 
-As of 9.0, Lucene/Solr uses [Gradle](https://gradle.org/) as the build
-system. Ant build support has been removed.
+There is ongoing work (see [LUCENE-9077](https://issues.apache.org/jira/browse/LUCENE-9077))
+to switch the legacy ant-based build system to [gradle](https://gradle.org/).
+Please give it a try!
+
+At the moment of writing, the gradle build requires precisely Java 11 
+(it may or may not work with newer Java versions).
 
 To build Lucene and Solr, run (`./` can be omitted on Windows):
 
 `./gradlew assemble`
 
-
-The command above packages a full distribution of Solr server; the 
+The command above also packages a full distribution of Solr server; the 
 package can be located at:
 
 `solr/packaging/build/solr-*`
 
 Note that the gradle build does not create or copy binaries throughout the
-source repository so you need to switch to the packaging output folder above;
-the rest of the instructions below remain identical. The packaging directory 
-is rewritten on each build. 
-
-For development, especially when you have created test indexes etc, use
-the `./gradlew dev` task which will copy binaries to `./solr/packaging/build/dev`
-but _only_ overwrite the binaries which will preserve your test setup.
+source repository (like ant build does) so you need to switch to the
+packaging output folder above; the rest of the instructions below remain
+identical.  
 
 ## Running Solr
 
@@ -86,24 +104,40 @@ Common options are described in some detail in solr/README.txt.  For an
 exhaustive treatment of options, run `bin/solr start -h` from the `solr/`
 directory.
 
+## Development/IDEs
+
+Ant can be used to generate project files compatible with most common IDEs.
+Run the ant command corresponding to your IDE of choice before attempting to
+import Lucene/Solr.
+
+- *Eclipse* - `ant eclipse` (See [this](https://cwiki.apache.org/confluence/display/solr/HowToConfigureEclipse) for details)
+- *IntelliJ* - `ant idea` (See [this](https://cwiki.apache.org/confluence/display/lucene/HowtoConfigureIntelliJ) for details)
+- *Netbeans* - `ant netbeans` (See [this](https://cwiki.apache.org/confluence/display/lucene/HowtoConfigureNetbeans) for details)
+
 ### Gradle build and IDE support
 
 - *IntelliJ* - IntelliJ idea can import the project out of the box. 
                Code formatting conventions should be manually adjusted. 
 - *Eclipse*  - Not tested.
 - *Netbeans* - Not tested.
 
+## Running Tests
 
-### Gradle build and tests
+The standard test suite can be run with the command:
 
-`./gradlew assemble` will build a runnable Solr as noted above.
+`ant test`
+
+Like Solr itself, the test-running can be customized or tailored in a number or
+ways.  For an exhaustive discussion of the options available, run:
+
+`ant test-help`
+
+### Gradle build and tests
 
-`./gradlew check` will assemble Lucene/Solr and run all validation
-  tasks unit tests.
+Run the following command to display an extensive help for running
+tests with gradle:
 
-`./gradlew help` will print a list of help commands for high-level tasks. One
-  of these is `helpAnt` that shows the gradle tasks corresponding to ant
-  targets you may be familiar with.
+`./gradlew helpTests`
 
 ## Contributing