howto_contribute: changing UX? then add to CHANGELOG.rst. and maybe docs

I've been forgetting to update the CHANGELOG.rst file. Maybe I'll remember it if I add a mention to the docs... either because it's doc'd or because of memories of this public confession.

Bugs closed: 397

Reviewed at https://rbcommons.com/s/twitter/r/992/
remember to update the CHANGELOG

Reviewed at https://rbcommons.com/s/twitter/r/993/
When a directory contains both a java_library and junit_test def, make sure the IDE understands this is a test pth, not a lib path

In our repo we have projects with BUILD files with 2 targets like:

```
java_libary(name='lib', ...)
junit_test(name='test', ...)
```

Sometimes, the ide_gen code saw the 'java_library' target first and considered that a regular source path, not a test source path, which causes tests to break in the IDE if they depend on libraries only defined in another test source path.  In project.iml, we would see the path defined with is_test="False"

This is just a workaround, as ide_gen still might not always add test folders properly:  If there is a java_library defined in a BUILD file under /src/test/java but no  junit_test, ide_gen mistakenly thinks this is plain source path, not a test source path.

Testing Done:
Re-ran goal idea on our test targets, the folders containing both tests and libraries that were previously 'blue' (regular source paths) are now green as they should be.

Bugs closed: 551

Reviewed at https://rbcommons.com/s/twitter/r/996/
initial draft of publishing a pants test infra package to facilitate external pants plugin testing

Bugs closed: 539

Reviewed at https://rbcommons.com/s/twitter/r/997/
Added source root tests, updated the internal data structure to include a tree.

Added source root tests, updated the internal data structure to include a tree to speed up the find() operation.

With 1000+ source roots in our environment, this appears to shave about 5 seconds off of a no-op build.

Testing Done:
Retrofitted tests for SourceRoot.
Added new unit tests for SourceRootTree data structure

CI passed at: https://travis-ci.org/pantsbuild/pants/builds/34713735

Bugs closed: 556

Reviewed at https://rbcommons.com/s/twitter/r/1003/
Add flag to dump project info output to file.

This file option will be used in intellij plugin.

Testing Done:
https://travis-ci.org/pantsbuild/pants/builds/34542731

This is OS Pants review for https://github.com/pantsbuild/intellij-pants-plugin/issues/5

Bugs closed: https://github.com/pantsbuild/intellij-pants-plugin/issues/5

Reviewed at https://rbcommons.com/s/twitter/r/998/
doc: update 3rdparty_py to mention requirements.txt and python_requirements

python_requirement() is nice, too, but it's not your only choice

Reviewed at https://rbcommons.com/s/twitter/r/995/
fixed --depmap-project-info for scala sources with the same package_prefix

the problem was that we were using same current_target  for all collected source roots. not the proper target this root is part of.

Testing Done:
tests are passing

Reviewed at https://rbcommons.com/s/twitter/r/990/
update release.sh and release.rst to include pantsbuild.pants.testinfra

Moving on, we'll publish two packages at the same time: pantsbuild.pants
and pantsbuild.pants.testinfra to PyPi. While they're sim-released, users
of pants can choose to install pants only if they don't have any
customization to pants thus avoiding the need of writing additional test
cases to which the pantsbuild.pants.testinfra would be helpful.

Testing Done:
I'm not the owner of pantsbuild.pants package on PyPi, so all my testing are local:

build-support/bin/release.sh -t
build-support/bin/release.sh -n

tested both. For the '-n' dry-run, I've also manually injected some failures at pants, pants_testinfra build stages, as well some failures in their testing commands, to have verified the proper command chaining behavior of the bash script.

Bugs closed: 539

Reviewed at https://rbcommons.com/s/twitter/r/1004/
Adds the --<goal>-use-source-root for IDE project generation tasks.

The option will put one entry for each source_root registered that has an active path in the project.
This is useful for Maven style layouts.

Testing Done:
Added unit test and integration test.

Manually tested with:

  pants goal idea testprojects/maven_layout:: --idea-use-source-root

CI is running.

Bugs closed: 558

Reviewed at https://rbcommons.com/s/twitter/r/1006/
Skipping a doc phase should result in transitive deps being skipped as well.

When `--doc-javadoc-skip` or `--doc-scaladoc-skip` are passed to a transitive publish, products generated by those goals will not be available, and should not be depended on in the Ivy javadoc configuration that JarPublish generates. Otherwise, Ivy will fail to resolve the transitive `javadoc` configuration during publishing.

* Expand existing targets to test transitive publishing of java/scala
* Simplify to-string for jar_coordinate of pushdb entries
* Don`t request docs unless they are available for all transitive targets

Testing Done:
new test, and manual publishing with --doc-scaladoc-skip and --doc-javadoc-skip

Reviewed at https://rbcommons.com/s/twitter/r/1011/
depmap KeyError fix

Testing Done:
ci

Reviewed at https://rbcommons.com/s/twitter/r/1015/
update and narrow down our "setting up Pants is hard" message

pantsbuild.pants is is a thing. So stop saying it's not installable.

We had commented out stuff about how to install it. Un-comment it.

For a venv-y example, see twitter/commons; not pants' repo, that was only true for a brief time.

BUT, setting up Pants in your code workspace still requires a PhD in Pants-ology. So shift our scary warning over to the setup_repo page.

Reviewed at https://rbcommons.com/s/twitter/r/1007/
Fixup test deps

These were revealed broken by running in non-fast mode.

Testing Done:
$ rm -rf pants.pex dist/ && ./pants build tests/python/pants_test:all

CI is went green here: https://travis-ci.org/pantsbuild/pants/builds/34972075

Bugs closed: 369, 569

Reviewed at https://rbcommons.com/s/twitter/r/1016/
Changes the behavior of goal idea to create a subdirectory named for the project name.

IntelliJ will fail to load the first time if you change the name and try to write the project into
the same directory as an existing project.

Also, enhanced the integration check to examine the contents of the project file when launching "hello"

Testing Done:
Manually confirmed the error "Cannot load module file '/Users/zundel/Development/java/squarepants/idea/foo4568.iml':
File /Users/zundel/Development/java/squarepants/idea/foo4568.iml does not exist
Would you like to remove module 'foo4568' from the project?"

does not occur any more when you change the project name.

Bugs closed: 564, 571

Reviewed at https://rbcommons.com/s/twitter/r/1019/
Got ivy to map in javadoc and source jars for pants goal idea.

This involved a fair amount of finagling with conf variables spread across ivy_* and ide files,
and some changes to the ivy mustache. The mechanism by which confs are currently passed around
does not seem very robust. The whole system would probably benefit from some refactoring to
abstract away ivy's inner workings and streamline generic mapping settings; it would be nice to
have an abstract interface for mapping jar files. This could  also make it easier to deal with
failing downloads, parallelization, or using a different jar mapping tool, but all that can
wait for an entirely different review.

Also cleaned up some style issues that got missed in the last patch for the idea goal.

Don't do extra work if no one wants sources.

(cherry picked from commit c3318b7d6668fad4facd75b1bbe81cee4773b2eb)
Added --idea-exclude-maven-target to get exclude IntelliJ from indexing 'target' directories.
If you are running maven and pants side by side, these 'target' files contain duplicates of a lot
resources and other cruft you don't want to see when you search.

(cherry picked from commit 83488471c7242ea91eb047192a065466c8e8cc9a)

Conflicts:
	tests/python/pants_test/tasks/test_idea_integration.py