Custom Block Plugin upgrade 2.x to 3.x leaves invalid block contexts

[ctgraham]

Describe the bug
The upgrade from 2.x to 3.x does not modify the block context of custom blocks, leaving them orphaned if they existed in BLOCK_CONTEXT_RIGHT_SIDEBAR or BLOCK_CONTEXT_HOMEPAGE

To Reproduce
Steps to reproduce the behavior:

1. Add custom blocks to a context other than the left sidebar in OJS 2.x
2. Upgrade to OJS 3.1.2
3. Navigate to Website Settings -> Appearance
4. Custom blocks to not appear in the Sidebar or Unselected section of Sidebar Management.

What application are you using?
OJS 3.1.2

Additional information
Original contexts were:

pkp-lib/classes/plugins/BlockPlugin.inc.php

Lines 16 to 18 in 097e08e

	define('BLOCK_CONTEXT_LEFT_SIDEBAR', 0x00000001);
	define('BLOCK_CONTEXT_RIGHT_SIDEBAR', 0x00000002);
	define('BLOCK_CONTEXT_HOMEPAGE', 0x00000003);

Contexts for 3.1.2 were:

pkp-lib/classes/plugins/BlockPlugin.inc.php

Lines 16 to 17 in 957d926

	define('BLOCK_CONTEXT_SIDEBAR', 0x00000001);
	define('BLOCK_CONTEXT_HOMEPAGE', 0x00000003);

But, only BLOCK_CONTEXT_SIDEBAR is considered:

pkp-lib/controllers/listbuilder/settings/BlockPluginsListbuilderHandler.inc.php

Lines 89 to 91 in 957d926

	case BLOCK_CONTEXT_SIDEBAR:
	$sidebarBlockPlugins[$key] = $plugins[$key];
	break;

But then this constant is entirely removed in 3.2:
a76bac7#diff-70caff5ef9a513397af1833a3e2a3c7c

[ctgraham]

Other blocks are handled here:
https://github.com/pkp/ojs/blob/a4768a0a5c7cf12618574eefdb7557f8c38ebc29/dbscripts/xml/upgrade/3.1.0_update.xml#L20-L22

[asmecher]

@ctgraham, forgive me for losing track of this one -- what is the status of the open PRs linked here?

[ctgraham]

Heh. I was just looking for that horrible installFilters hijack yesterday. There it is.

I think these are still good for merge. stable-3_1_2 is releasable as 1.3 for 3.1.2, and master is releasable as 1.3.1 for 3.2. I haven't actually run the plugin in 3.2, though.

[asmecher]

I've added Travis tests to stable-3_2_1 and master branches of the custom block plugin, and will now start looking at the PRs for the stable-3_2_1 branch, thanks!