Issue 430 — Execution tree shows empty when platform filter is -1 sentinel

Issue: https://github.com/sebiboga/testlink-upgraded/issues/430 Status: FIXED (commit 01b11e300, verified live end-to-end)

Symptom

On a test plan without platforms, the execution tree hid every executed test case. The latest-execution subquery was filtered with AND EE.platform_id = -1 (the "no platform selected" sentinel), which can never match because executions.platform_id stores 0 for platform-less plans. The exec union INNER JOINs that empty subquery and returns nothing, while the not-run union is suppressed by the existence of real executions — so executed cases vanished from the tree.

Root cause chain

1. tlTestCaseFilterControl::init_setting_platform() (lib/functions/tlTestCaseFilterControl.class.php:1312-1320) — when the plan has no linked platforms it sets settings['setting_platform']['selected'] = -1 and returns.
2. The tree builder maps the setting verbatim into filters (lib/functions/execTreeMenu.inc.php:330: 'platform_id' => 'setting_platform') and calls testplan::getLinkedForExecTree() (execTreeMenu.inc.php:146).
3. Pre-fix getLinkedForExecTree() concatenated the filter unconditionally: AND EE.platform_id = -1 → $sqlLEBBP empty → exec union yields zero rows.

The fix

lib/functions/testplan.class.php:6122-6126: filter only on real platform ids — if (!is_null($my['filters']['platform_id']) && $my['filters']['platform_id'] > 0) — the same > 0 convention initGetLinkedForTree() already used for TPTCV. Second defense layer (added under #420): lib/execute/execSetResults.php:2318-2320 normalizes any negative platform value to the DB convention 0.

Verification (fresh DB + fixtures via XMLRPC API)

Fixtures: project Proj430(1)/P430, plan TP430(2) with zero platforms, build B430(1), TC430-A(ext P430-1) executed Passed, TC430-B(ext P430-2) executed Failed (executions.platform_id = 0 on both rows).

#	Case	Expected	Result
1	DB mechanism check	subquery with verbatim -1 → EMPTY SET; without clause → 2 rows	PASS
2	Exec navigator tree	counters (2)(0,1,1,0), both leaves visible	PASS
3	Exec form via leaf click (setting_platform=-1 in URL)	form renders with latest execution data, not "No data available"	PASS
4	Event Viewer delta from the exec-tree path	no new Error/Warning attributable to this path	PASS

Regression suite: tmp/TLU_Test_Cases.md, Suite 430.