Common Contrib Build

The situation

Multi-module clojure-contrib in one repository has not worked well
- Build is complicated and slow
- Still hard for authors to work on their libs
We will have more projects under the org.clojure umbrella
- New contrib libraries: nrepl, unify, finger-tree
- More on the way
Current Clojure release process involves manual steps

For users
- 1. Find release versions
- 2. IDE / tool support
- 3. Get just the stuff they need, without stuff they don't
- 4. Easy-to-use distributions containing multiple libraries known to work together
For developers
- 1. Build / release automation
- 2. Unified build / release process across projects
- 3. IDE / tool support

patch CLJ-681has been applied
- Keeps the Ant build the way it is now
  - Developers can continue to use Ant for local builds
- Maven controls the build/test/release process on Hudson
  - Real pom.xml
  - Declares Sonatype's oss-parent POM as a parent
    - Enables releases to public open-source repositories managed by Sonatype
  - Calls out to Ant for Clojure-specific compile and test phases
    - Temporary until we have better plugins, see Clojure Maven Plugin and Why Maven?
SNAPSHOT releases automatically deployed by hudson
Numbered releases controlled by Hudson/Maven
- Only Clojure language committers may initiate a release

To promote new contrib projects, see Guidelines for Clojure Contrib committers
To release, see How to Make Releases
Git repositories
- New contrib libs get their own repos under the Clojure github organization
- Each lib gets one or more "owners" who have commit access
- Library authors still use JIRA %2B patches to accept contributions
- All contributors must have a CA
JIRA
- Each contrib library/project will get its own JIRA
Maven
- Contrib projects must be built with Maven 2
- All contrib POMs must declare org.clojure:pom.contribas a parent
  - Inherits from Sonatype's OSS POM
  - Defines release process (OSS snapshots %2B staging)
  - Set dependency on latest Clojure release (1.3.0-alpha5)
    - May be overridden on a per-project basis
    - Support building with a local Clojure JAR
  - Inherits from pom.oss-deploy
  - Sets license to EPL
  - Configures Java 1.5 as a target
  - Sets common plugin/build configurations
  - Uses com.theoryinpractise:clojure-maven-plugin
    - Temporary until we have better plugins, see Clojure Maven Plugin and Why Maven?
  - Defaults to source-only JAR, override to AOT-compile only when necessary

The old monolithic build structure is deprecated
- The 1.2.0 release is available at clojure.org and the Maven Central Repository
The interim multi-module build structure is deprecated
- Module releases up to 1.3.0-alpha4 are available in the build.clojure.org release repository
  - These are source-only JARs wherever possible
  - They should be compatible with any version of Clojure
- The multi-module build does not work with Clojure 1.3.0-alpha5 and later
Libraries with community demand and willing maintainers will become "new" contrib projects as above
The "classic" clojure-contrib JIRAis deprecated
- Important issues should be reposted in the new per-project JIRAs

DONE Clean up / finalize pom.contrib
- Replace 3-level inheritance (pom.oss-deploy -> pom.baseline -> pom.contrib) with just pom.contrib
DONE Finalize contrib project Hudson config
DONE Figure out how to give Hudson permissions to contrib authors (Stuart Sierra & Aaron Bedra)
DONE Create new Hudson job for finger-tree
DONE Figure out how to manage many similar Hudson configurations (Chas Emerick & Stuart Sierra)
- See Keeping Hudson config in version control
- See Hudson API
TODO verify Sonatype release goals do the right thing in the presence of multiple staging repositories
TODO Get older releases into Maven Central?
TODO Redirect repositories at build.clojure.org to OSS Sonatype
- Assuming we roll all existing releases into central, we only need to set up redirects for /snapshots

Improve the Maven build process; see Clojure Maven Plugin
Better Clojure-from-Java interface (see CLJ-452)
Aggregate projects that package many contrib libraries in one distribution
Testing harness to build/test many Clojure libraries with a locally-built Clojure JAR
Making the build process better
- Improve clojure.lang.Compile
  - Investigate why compilation sometimes pauses for a long time (minutes) at the end
  - Investigate if core needs explicit compilation order
- Investigate Maven 3
- Investigate Polyglot Maven
- Documentation: how do I do X, Y, or Z?
- Write more plugins
  - Not hard
  - Possible in Clojure; see clojure-mojo-example
  - More portable than shell scripts
- Developing other non-Maven tools
  - Will require a lot of work to match what Maven can do
  - Not a Clojure/core priority

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