JInstaller improvements/adjustments

[hieblmedia]

1. The package adapter executes the install method twice. This can insert dublicate database entries.
   See: http://joomlacode.org/gf/project/joomla/tracker/?action=TrackerItemEdit&tracker_item_id=27802
2. On some install adapters a check is_a($updateElement, 'JXMLElement') return always true and force an update. This is not desirable.
3. The template install adapter never return an existing extension id (setQuery was not set). This forces and update also and create dublicate database entries in the extensions table (also template styles). Updated query with exception and direct rollback.

[joomla-jenkins]

Build triggered by changes to the base.

Unit testing complete. There were 0 failures and 0 errors from 1905 tests and 11045 assertions.
Checkstyle analysis reported 165 warnings and 3 errors.

[hieblmedia]

The template installer issue is very important to fix. (commit: f2eefd8)

Becuase,
if a template is already installed the, database entry of a (random?) core extension would be overwritten. This is very very bad.

[hieblmedia]

Hm i have this exception handling from the plugin adapter.
You mean to remove the new 'try...catch' part?

[realityking]

Not remove it, supplement it with the legacy error handling. I just had a quick glance at the plug-in adapter, I think we gotta fix that one too.

[hieblmedia]

Can you explain me an example? I don't know what is to do for error legacy support.

[realityking]

Here's an example of using both methods: https://github.com/joomla/joomla-platform/blob/staging/libraries/joomla/database/table.php#L528 (up to line 546)

[joomla-jenkins]

Build triggered by changes to the head.

Unit testing complete. There were 0 failures and 0 errors from 1991 tests and 11149 assertions.
Checkstyle analysis reported 165 warnings and 3 errors.

[chdemko]

@hieblmedia There remains 3 errors for the code style

[hieblmedia]

Code style errors fixed

[joomla-jenkins]

Build triggered by changes to the head.

Unit testing complete. There were 0 failures and 0 errors from 1991 tests and 11151 assertions.
Checkstyle analysis reported 165 warnings and 0 errors.