resultsByTSuite Exec-Span Null Map + $fieldList Fix

Issue #587

Fixed: opening lib/results/resultsByTSuite.php?tplan_id=<plan-with-linked-cases-but-zero-executions>&format=0 rendered HTTP 200 but logged 4 fresh E_WARNING events on every call:

E_WARNING Undefined variable $fieldList - tlTestPlanMetrics.class.php - Line 3657
E_WARNING Trying to access array offset on null - resultsByTSuite.php - Line 72
E_WARNING Trying to access array offset on null - templates_c/…show_table_with_exec_span.inc.tpl.php - Line 39
E_WARNING Trying to access array offset on null - templates_c/…show_table_with_exec_span.inc.tpl.php - Line 42

Warning 1 fires even when executions exist; warnings 2–4 need a plan with zero rows in executions.

Root Cause

Two-part pre-existing legacy defect in the "First & Latest Execution" span path of the Metrics by L1/L2 Test Suite report:

1. getExecTimeSpan() (lib/functions/tlTestPlanMetrics.class.php:3657) used $fieldList .= implode(',', $context); without ever initialising $fieldList. PHP tolerates .= on an undefined variable (treats it as '') but logs an E_WARNING every single call.

2. No-execution plans make the aggregate SELECT MIN/MAX(execution_ts) … GROUP BY … return no rows, so fetchRowsIntoMap() / fetchRowsIntoMap2l() return NULL and the method returns null. The controller (lib/results/resultsByTSuite.php:70-72) then read $span[$args->tplan_id] unguarded → "array offset on null", stored [0] => null into $gui->spanByPlatform, and the Dashio partial show_table_with_exec_span.inc.tpl passed its {if null != $gui->spanByPlatform} check (a non-empty array holding one null is not null) and dereferenced ['begin'] / ['end'] of the null entry → the two template warnings.

The Fix — approach

Three minimal guards, each at the exact defect site:

// tlTestPlanMetrics.class.php:3657
$fieldList = implode(',', $context);        // was .=

// resultsByTSuite.php (both branches)
$gui->spanByPlatform = isset($span[$args->tplan_id]) ? $span[$args->tplan_id] : null;

{* show_table_with_exec_span.inc.tpl (dashio + tl-classic) *}
{if null != $gui->spanByPlatform && isset($gui->spanByPlatform[$platId])}

Why this shape:

• isset() on a possibly-null variable/array is warning-free under PHP 8 and covers all three null shapes: whole map null, platform key missing (a platform with no executions inside a multi-platform plan), key present but null (the [0] => null no-platform case).
• Guarding the caller keeps getExecTimeSpan()'s existing contract (map or null) intact for any future caller; the template guard makes rendering skip only the two date lines when a given platform has no span data.
• Alternatives rejected: casting the fetch result to (array) inside getExecTimeSpan() alone would still warn ("undefined array key") at the controller; guarding only the template would leave the controller warning.

The tl-classic copy of the partial got the identical isset() addition so both themes stay consistent.

Verification

Fixture: project 900001 / plan 900002 / build 900003 / nested suites TS TOP > TS CHILD / TC-1 v1 linked, zero executions initially.

Step	Result
Zero-executions load	HTTP 200, 0 new events (was 4)
One execution inserted → reload	First/Latest Execution dates render correctly, 0 new events
Multi-platform plan (P-Busy with execution, P-Idle without)	P-Busy section renders span dates, no warnings for the idle platform
Browser pass (headless Chrome, admin/admin) + Event Viewer	only normal AUDIT login event, no Error/Warning
Code review subagent over full diff	PASS, no required findings

Regression suite: Regression — Issue #587 in tmp/TLU_Test_Cases.md.

Follow-up bugs discovered during verification

Filed separately (kept out of this fix to stay minimal):

• #588 dashio copy of show_table_with_exec_span.inc.tpl lacks the property_exists($gui,'spanByPlatform') guard the tl-classic copy has → one "Undefined property" E_WARNING per baselinel1l2 page render.
• #589 saveForBaseline on a zero-execution plan still dereferences the null span and INSERTs empty begin/end timestamps into baseline_l1l2_context.

Files changed

• lib/functions/tlTestPlanMetrics.class.php — $fieldList initialisation in getExecTimeSpan() (~3657)
• lib/results/resultsByTSuite.php — isset() guards for the span map reads (~69-75)
• gui/templates/dashio/results/show_table_with_exec_span.inc.tpl — per-platform isset() guard (:14)
• gui/templates/tl-classic/results/show_table_with_exec_span.inc.tpl — same guard (:16)

Screenshots