Bugfix Issue 1016 formatTestCaseIdentity broken dead code

Issue #1016 — testcase.class.php: formatTestCaseIdentity() is broken dead code (undefined $tc_id, unguarded $path2root[0])

Issue: #1016 Commit: b36f6bff4 (fix) Status: VERIFIED-FIXED (2026-09-05)

Symptom

testcase::formatTestCaseIdentity($id, $external_id = null) in lib/functions/testcase.class.php was dead code (zero call sites in the whole repo) but broken in three independent ways:

1. The body referenced $tc_id, which is never defined — the parameter is $id → PHP 8 E_WARNING "Undefined variable $tc_id".
2. $path2root[0]['parent_id'] was dereferenced with no null/empty guard → when tree_manager->get_path() returns NULL, PHP 8 raises E_WARNING "Trying to access array offset on null" twice and $tproject_id stays NULL.
3. getTestCasePrefix($tproject_id) was then called with NULL → SELECT prefix FROM testprojects WHERE id = → MySQL 1064 → request dies with the "DB Access Error" page. The function also computed $tcasePrefix without ever returning it.

The bug is latent today (nothing calls the function), which is why it never surfaced at runtime — it is a mine, not a live regression.

Investigation

Repo-wide grep (*.php, *.tpl, *.html, *.js) found exactly two matches, both in lib/functions/testcase.class.php: the PHPDoc comment and the definition. No caller exists.

A in-app probe (framework bootstrapped via config.inc.php + common.php + doDBConnect() + new testcase($db)) replicating the body line-by-line measured:

path2root = NULL          # get_path($tc_id) — $tc_id UNDEFINED → NULL
tproject_id = NULL        # $path2root[0]['parent_id'] on NULL
[2] Undefined variable $tc_id
[2] Trying to access array offset on null   # [0]
[2] Trying to access array offset on null   # ['parent_id']

A second probe calling the real method formatTestCaseIdentity(1) died with:

#2 testproject.class.php(1002): database->fetchOneValue(...)
#3 testcase.class.php(2153): testproject->getTestCasePrefix(NULL)

and logged log_level=1 ERROR "SQL 1064 … SELECT prefix FROM testprojects WHERE id = " into the events table — the same bug class as #1011.

Root cause chain

1. lib/functions/testcase.class.php (formerly 2149-2155) — formatTestCaseIdentity($id, $external_id=null); zero callers → dead code.
2. Line 2151: $path2root = $this->tree_manager->get_path($tc_id); — $tc_id undefined (parameter $id); evaluates to NULL.
3. tree::get_path(NULL) → returns NULL (no node found, _get_path() sets $node_list = null).
4. Line 2152: $tproject_id = $path2root[0]['parent_id']; — unguarded index on NULL → E_WARNING; $tproject_id = NULL.
5. Line 2153: getTestCasePrefix(NULL) → raw WHERE id = → MySQL 1064, request dies.

The whole function is a legacy copy-paste leftover of getPrefix() (same file) that was never finished (no return value) and was never wired to any call site.

Fix (minimal, matches the issue's "remove or fix" options)

Remove the dead function and its PHPDoc block (single hunk, ~16 deleted lines). Rationale: the function has no callers, is broken three ways, and is semantically incomplete even after a typo fix (it computes $tcasePrefix but never returns it) — resurrecting it would leave a still-useless half-function. The #1011-style fix ($tc_id→$id plus empty-path guard) was the alternative; it was rejected because it would make dead code "work" for no caller's benefit. getPrefix() and its #1011 empty-tree-path guard are untouched.

Why this method (alternatives rejected)

• Alternative A (fix the typo + add the guard): keeps a function nothing calls already broken for a third reason (no return value, no defined purpose in any caller). Rejected.
• Alternative B (leave it): keeps the same latent SQL-1064 mine documented in #1011's follow-up. Rejected — the whole point of the follow-up issue is to eliminate the class.
• Chosen (remove): smallest correct diff, eliminates the latent path entirely, zero behavioural risk because there are zero call sites.

Verification

• php -l lib/functions/testcase.class.php — no syntax errors.
• Repo-wide grep formatTestCaseIdentity → 0 matches (dead code gone).
• getPrefix(3) on fixture (project PROBE id=1, suite id=2, tc id=3) → array('PROBE','1') — valid deep-link path unchanged.
• getPrefix(99999999) / getPrefix(null) → array(null, null) — #1011 guard intact, no WARNING/ERROR events.
• getPrefix(3, 1) fast path → array('PROBE', 1) — unchanged.
• Browser: admin/admin login → landing shells render, no console errors; modern tcView.html?tcase_id=3&tproject_id=1 renders its shell cleanly.
• Event Viewer / events table: the only ERROR present pre-purge was the pre-fix reproduction artifact (id=1, SQL 1064, fired 1788646516 before the fix); post-fix activity logged only INFO AUDIT rows. Events were then purged for the clean screenshot below (0 ERROR / 0 WARNING / 0 DEBUG / 0 L18N). No new Error/Warning introduced.
• Regression suite TC-1016.1..TC-1016.7 appended to tmp/TLU_Test_Cases.md (7/7 PASS).

Screenshots

Files changed

• lib/functions/testcase.class.php (−17) — removed dead formatTestCaseIdentity() + PHPDoc.
• tmp/TLU_Test_Cases.md — regression suite TC-1016.* (7/7 PASS, local file).
• docs/screenshots/issue-1016-eventviewer-clean.png — evidence.