docs: Move existing documentation into new Contributor Guide and add Getting Started section

.github/workflows/benchmark-tpch.yml

@@ -25,10 +25,12 @@ on:
   push:
     paths-ignore:
       - "doc/**"
+      - "docs/**"
       - "**.md"
   pull_request:
     paths-ignore:
       - "doc/**"
+      - "docs/**"
       - "**.md"
   # manual trigger
   # https://docs.github.com/en/actions/managing-workflow-runs/manually-running-a-workflow

.github/workflows/benchmark.yml

@@ -25,10 +25,12 @@ on:
   push:
     paths-ignore:
       - "doc/**"
+      - "docs/**"
       - "**.md"
   pull_request:
     paths-ignore:
       - "doc/**"
+      - "docs/**"
       - "**.md"
   # manual trigger
   # https://docs.github.com/en/actions/managing-workflow-runs/manually-running-a-workflow

.github/workflows/pr_build.yml

@@ -25,10 +25,12 @@ on:
   push:
     paths-ignore:
       - "doc/**"
+      - "docs/**"
       - "**.md"
   pull_request:
     paths-ignore:
       - "doc/**"
+      - "docs/**"
       - "**.md"
   # manual trigger
   # https://docs.github.com/en/actions/managing-workflow-runs/manually-running-a-workflow

.github/workflows/spark_sql_test.yml

@@ -25,10 +25,12 @@ on:
   push:
     paths-ignore:
       - "doc/**"
+      - "docs/**"
       - "**.md"
   pull_request:
     paths-ignore:
       - "doc/**"
+      - "docs/**"
       - "**.md"
   # manual trigger
   # https://docs.github.com/en/actions/managing-workflow-runs/manually-running-a-workflow

docs/source/contributor-guide/contributing.md

@@ -0,0 +1,54 @@
+<!---
+  Licensed to the Apache Software Foundation (ASF) under one
+  or more contributor license agreements.  See the NOTICE file
+  distributed with this work for additional information
+  regarding copyright ownership.  The ASF licenses this file
+  to you under the Apache License, Version 2.0 (the
+  "License"); you may not use this file except in compliance
+  with the License.  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing,
+  software distributed under the License is distributed on an
+  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+  KIND, either express or implied.  See the License for the
+  specific language governing permissions and limitations
+  under the License.
+-->
+
+# Contributing to Apache DataFusion Comet
+
+We welcome contributions to Comet in many areas, and encourage new contributors to get involved.
+
+Here are some areas where you can help:
+
+- Testing Comet with existing Spark jobs and reporting issues for any bugs or performance issues
+- Contributing code to support Spark expressions, operators, and data types that are not currently supported
+- Reviewing pull requests and helping to test new features for correctness and performance
+- Improving documentation
+
+## Finding issues to work on
+
+We maintain a list of good first issues in GitHub [here](https://github.com/apache/datafusion-comet/issues?q=is%3Aopen+is%3Aissue+label%3A%22good+first+issue%22).
+
+The list of currently supported Spark expressions can be found at
+
+## Reporting issues
+
+We use [GitHub issues](https://github.com/apache/datafusion-comet/issues) for bug reports and feature requests.
+
+## Asking for Help
+
+The Comet project uses the same Slack and Discord channels as the main Apache DataFusion project. See details at
+[Apache DataFusion Communications]. There are dedicated Comet channels in both Slack and Discord.
+
+## Regular public meetings
+
+The Comet contributors hold regular video calls where new and current contributors are welcome to ask questions and
+coordinate on issues that they are working on.
+
+See the [Apache DataFusion Comet community meeting] Google document for more information.
+
+[Apache DataFusion Communications]: https://datafusion.apache.org/contributor-guide/communication.html
+[Apache DataFusion Comet community meeting]: https://docs.google.com/document/d/1NBpkIAuU7O9h8Br5CbFksDhX-L9TyO9wmGLPMe0Plc8/edit?usp=sharing

DEBUGGING.md → docs/source/contributor-guide/debugging.md

@@ -20,12 +20,13 @@ under the License.
 # Comet Debugging Guide
 
 This HOWTO describes how to debug JVM code and Native code concurrently. The guide assumes you have:
+
 1. Intellij as the Java IDE
 2. CLion as the Native IDE. For Rust code, the CLion Rust language plugin is required. Note that the
-Intellij Rust plugin is not sufficient.
+   Intellij Rust plugin is not sufficient.
 3. CLion/LLDB as the native debugger. CLion ships with a bundled LLDB and the Rust community has
-its own packaging of LLDB (`lldb-rust`). Both provide a better display of Rust symbols than plain
-LLDB or the LLDB that is bundled with XCode. We will use the LLDB packaged with CLion for this guide.
+   its own packaging of LLDB (`lldb-rust`). Both provide a better display of Rust symbols than plain
+   LLDB or the LLDB that is bundled with XCode. We will use the LLDB packaged with CLion for this guide.
 4. We will use a Comet _unit_ test as the canonical use case.
 
 _Caveat: The steps here have only been tested with JDK 11_ on Mac (M1)
@@ -42,21 +43,24 @@ use advanced `lldb` debugging.
 1. Add a Debug Configuration for the unit test
 
 1. In the Debug Configuration for that unit test add `-Xint` as a JVM parameter. This option is
-undocumented *magic*. Without this, the LLDB debugger hits a EXC_BAD_ACCESS (or EXC_BAD_INSTRUCTION) from
-which one cannot recover.
+   undocumented _magic_. Without this, the LLDB debugger hits a EXC_BAD_ACCESS (or EXC_BAD_INSTRUCTION) from
+   which one cannot recover.
+
+1. Add a println to the unit test to print the PID of the JVM process. (jps can also be used but this is less error prone if you have multiple jvm processes running)
+
+   ```JDK8
+        println("Waiting for Debugger: PID - ", ManagementFactory.getRuntimeMXBean().getName())
+   ```
+
+   This will print something like : `PID@your_machine_name`.
 
-1. Add  a println to the unit test to print the PID of the JVM process. (jps can also be used but this is less error prone if you have multiple jvm processes running)
-     ``` JDK8
-          println("Waiting for Debugger: PID - ", ManagementFactory.getRuntimeMXBean().getName())
-     ```
-      This will print something like : `PID@your_machine_name`.
+   For JDK9 and newer
 
-     For JDK9 and newer
-     ```JDK9
-          println("Waiting for Debugger: PID - ", ProcessHandle.current.pid)
-     ```
+   ```JDK9
+        println("Waiting for Debugger: PID - ", ProcessHandle.current.pid)
+   ```
 
-     ==> Note the PID
+   ==> Note the PID
 
 1. Debug-run the test in Intellij and wait for the breakpoint to be hit
 
@@ -96,7 +100,8 @@ Detecting the debugger
 https://stackoverflow.com/questions/5393403/can-a-java-application-detect-that-a-debugger-is-attached#:~:text=No.,to%20let%20your%20app%20continue.&text=I%20know%20that%20those%20are,meant%20with%20my%20first%20phrase).
 
 # Verbose debug
-By default, Comet outputs the exception details specific for Comet. 
+
+By default, Comet outputs the exception details specific for Comet.
 
 ```scala
 scala> spark.sql("my_failing_query").show(false)
@@ -112,7 +117,7 @@ This was likely caused by a bug in DataFusion's code and we would welcome that y
 ```
 
 There is a verbose exception option by leveraging DataFusion [backtraces](https://arrow.apache.org/datafusion/user-guide/example-usage.html#enable-backtraces)
-This option allows to append native DataFusion stacktrace to the original error message. 
+This option allows to append native DataFusion stacktrace to the original error message.
 To enable this option with Comet it is needed to include `backtrace` feature in [Cargo.toml](https://github.com/apache/arrow-datafusion-comet/blob/main/core/Cargo.toml) for DataFusion dependencies
 
 ```
@@ -129,15 +134,16 @@ RUST_BACKTRACE=1 $SPARK_HOME/spark-shell --jars spark/target/comet-spark-spark3.
 ```
 
 Get the expanded exception details
+
 ```scala
 scala> spark.sql("my_failing_query").show(false)
 24/03/05 17:00:49 ERROR Executor: Exception in task 0.0 in stage 0.0 (TID 0)
 org.apache.comet.CometNativeException: Internal error: MIN/MAX is not expected to receive scalars of incompatible types (Date32("NULL"), Int32(15901))
 
-backtrace:    
+backtrace:
   0: std::backtrace::Backtrace::create
   1: datafusion_physical_expr::aggregate::min_max::min
-  2: <datafusion_physical_expr::aggregate::min_max::MinAccumulator as datafusion_expr::accumulator::Accumulator>::update_batch 
+  2: <datafusion_physical_expr::aggregate::min_max::MinAccumulator as datafusion_expr::accumulator::Accumulator>::update_batch
   3: <futures_util::stream::stream::fuse::Fuse<S> as futures_core::stream::Stream>::poll_next
   4: comet::execution::jni_api::Java_org_apache_comet_Native_executePlan::{{closure}}
   5: _Java_org_apache_comet_Native_executePlan
@@ -151,6 +157,8 @@ at org.apache.comet.CometExecIterator.hasNext(CometExecIterator.scala:126)
 (reduced)
 
 ```
+
 Note:
+
 - The backtrace coverage in DataFusion is still improving. So there is a chance the error still not covered, if so feel free to file a [ticket](https://github.com/apache/arrow-datafusion/issues)
 - The backtrace evaluation comes with performance cost and intended mostly for debugging purposes

DEVELOPMENT.md → docs/source/contributor-guide/development.md

@@ -49,25 +49,29 @@ A few common commands are specified in project's `Makefile`:
 - `make clean`: clean up the workspace
 - `bin/comet-spark-shell -d . -o spark/target/` run Comet spark shell for V1 datasources
 - `bin/comet-spark-shell -d . -o spark/target/ --conf spark.sql.sources.useV1SourceList=""` run Comet spark shell for V2 datasources
-	
+
 ## Development Environment
+
 Comet is a multi-language project with native code written in Rust and JVM code written in Java and Scala.
-For Rust code, the CLion IDE is recommended. For JVM code, IntelliJ IDEA is recommended. 
+For Rust code, the CLion IDE is recommended. For JVM code, IntelliJ IDEA is recommended.
 
 Before opening the project in an IDE, make sure to run `make` first to generate the necessary files for the IDEs. Currently, it's mostly about
 generating protobuf message classes for the JVM side. It's only required to run `make` once after cloning the repo.
 
 ### IntelliJ IDEA
-First make sure to install the Scala plugin in IntelliJ IDEA. 
+
+First make sure to install the Scala plugin in IntelliJ IDEA.
 After that, you can open the project in IntelliJ IDEA. The IDE should automatically detect the project structure and import as a Maven project.
 
 ### CLion
+
 First make sure to install the Rust plugin in CLion or you can use the dedicated Rust IDE: RustRover.
 After that you can open the project in CLion. The IDE should automatically detect the project structure and import as a Cargo project.
 
 ### Running Tests in IDEA
+
 Like other Maven projects, you can run tests in IntelliJ IDEA by right-clicking on the test class or test method and selecting "Run" or "Debug".
-However if the tests is related to the native side. Please make sure to run `make core`  or `cd core && cargo build` before running the tests in IDEA.
+However if the tests is related to the native side. Please make sure to run `make core` or `cd core && cargo build` before running the tests in IDEA.
 
 ## Benchmark
 
@@ -82,9 +86,11 @@ To run TPC-H or TPC-DS micro benchmarks, please follow the instructions
 in the respective source code, e.g., `CometTPCHQueryBenchmark`.
 
 ## Debugging
+
 Comet is a multi-language project with native code written in Rust and JVM code written in Java and Scala.
-It is possible to debug both native and JVM code concurrently as described in the [DEBUGGING guide](DEBUGGING.md)
+It is possible to debug both native and JVM code concurrently as described in the [DEBUGGING guide](debugging)
 
 ## Submitting a Pull Request
-Comet uses `cargo fmt`, [Scalafix](https://github.com/scalacenter/scalafix) and [Spotless](https://github.com/diffplug/spotless/tree/main/plugin-maven) to 
-automatically format the code. Before submitting a pull request, you can simply run `make format` to format the code.
+
+Comet uses `cargo fmt`, [Scalafix](https://github.com/scalacenter/scalafix) and [Spotless](https://github.com/diffplug/spotless/tree/main/plugin-maven) to
+automatically format the code. Before submitting a pull request, you can simply run `make format` to format the code.

docs/source/index.rst

@@ -35,16 +35,23 @@ Apache DataFusion Comet
 Apache DataFusion Comet is an Apache Spark plugin that uses Apache DataFusion
 as a native runtime to achieve improvement in terms of query efficiency and query runtime.
 
-This documentation site is currently being developed. The most up-to-date documentation can be found in the
-GitHub repository at https://github.com/apache/datafusion-comet.
+.. _toc.links:
+.. toctree::
+   :maxdepth: 1
+   :caption: User Guide
+
+   Supported Expressions <user-guide/expressions>
+   user-guide/compatibility
 
 .. _toc.links:
 .. toctree::
    :maxdepth: 1
-   :caption: Project Links
+   :caption: Contributor Guide
 
-   compatibility
+   Getting Started <contributor-guide/contributing>
    Github and Issue Tracker <https://github.com/apache/datafusion-comet>
+   contributor-guide/development
+   contributor-guide/debugging
 
 .. _toc.asf-links:
 .. toctree::