What is Bach? And ideas for hack-commit-push 2021

[sormuras]

Hack.Commit.Push 2021

https://paris2021.hack-commit-pu.sh

What is Bach?

Bach is a lightweight Java build tool that orchestrates JDK tools for building modular Java projects.

By default, it tries its best to call the right tool at the right time with the right arguments.
Bach encourages developers to explore, learn, and master these foundation tools and
their options in order to allow a good understanding of what is really going on when
building a Java project. Pass those learnings and optimizations as fine-grained tweaks in
a declarative manner back to Bach using pure Java syntax.

• ▶ Very Short Video
  Quicker Java and JDK 16 compatibility - Inside Java Newscast #3

"[...] there's Bach. A lightweight Java build tool for modular Java projects. It has the JDK tools at its heart (javac, jlink and so forth)
and if your project lines up with their expectations, you need zero configuration."

• ▶ Very Long Video with @nipafx on his Twitch Channel
  Nicolai has Christian Stein on to learn about the latest iteration of his Java build tool Bach

The JDK contains a set of foundation tools but none of them guides developers from
processing Java source files into shippable products: be it a reusable modular JAR file
with its API documentation or an entire custom runtime image.

There exists however an implicit workflow encoded in the available tools and their options.
The (binary) output of one tool is the input of one or more other tools. With the
introduction of modules in Java 9 some structural parts of that workflow got promoted
into the language itself and resulted in explicit module-related tool options.

These structural information, encoded explicitly by developers in Java's module
descriptors (module-info.java files), serves as basic building blocks for Bach's project model.
Their location within the file tree, their module name, and their requires directives are
examples of such information. In addition, Bach defines an annotation named ProjectInfo
in order to let developers define extra configuration information.

Open Issues Tagged with Help Wanted

• https://github.com/sormuras/bach/issues?q=is%3Aissue+is%3Aopen+label%3A%22help+wanted%22

Examples

• Create new example projects
• Port an existing project

Documentation

• Update, extend existing Javadoc

Implement dedicated Tool's API

For example, The javac Command

public record Javac(List<String> arguments) implements Command<Javac> {

  /**
   * {@return new Javac instance with given destination directory}
   *
   * <p>Same as {@code .add("-d", directory)}
   *
   * @param directory specify where to place generated class files
   */
  public Javac destination(Path directory) {
    return with("-d", directory);
  }

}

• Rinse and repeat for other commonly used flags and options.

• Same, same for other tool classes defined in package com.github.sormuras.bach.tool according to their Tool Specifications.

Optimize creation of ModuleDescriptor for DeclaredModuleReference

• Compile (to memory) and read bytes via java.lang.module.ModuleDescriptor#read(...)
• Strip comments from Java source code in com.github.sormuras.bach.api.DeclaredModuleReference#parse(java.lang.String)

[sormuras]

Increase Code Coverage

• ... there are some lines (branches) not yet touched by any test case. Can you spot and touch (read: check) them?
• Learn how to write tests in the Modular World.

➡ Referenced in issue #234

[sormuras]

IDE Support

• Export an instance of Bach's Project model to an IDE configuration, like generating a proper .idea directory.
• Write an IDE plugin that imports and updates an IDE configuration based on Bach's Project model.