Deleting a single test case version (modern BFF POST /api/testcases/?action=delete_version) removes the tcversions + nodes_hierarchy entries but leaves orphaned testcase_platforms rows that reference the deleted version. Reproduced on every single-version delete (testcase TC Login, version with platforms Android/iOS/Windows assigned).

• After delete_version, SELECT tcversion_id,platform_id FROM testcase_platforms WHERE testcase_id=<tid> still returns the rows of the deleted version while tcversions / nodes_hierarchy no longer contain it.
• Manual cleanup was previously required: DELETE FROM testcase_platforms WHERE tcversion_id=<dead version>;

The same hole exists on the whole-test-case delete path (POST /api/testcases/?action=delete and legacy tcEdit doDelete), because both funnel through the same core delete routine.

Environment: http://localhost:8082 (PHP built-in server, docroot = repo root), MariaDB testlink, login admin/admin. Fresh-import DB; fixture rebuilt via SQL to mirror the reported layout: testproject Platform Demo (prefix PD), suite Suite A, testcase TC Login (node 3), tcversion node 4 (tcversions.id=4, v1), step node, platforms Android(1)/iOS(2)/Windows(3) enable_on_design=1, and testcase_platforms rows (3,4,1),(3,4,2),(3,4,3).

1. Login: curl -X POST -c /tmp/opencode/cookies.txt -H "X-Requested-With: XMLHttpRequest" -d 'login=admin&password=admin' http://localhost:8082/api/auth/login → {"status":"ok"}.
2. curl ... -X POST 'http://localhost:8082/api/testcases/?action=create_version' -d '{"tcase_id":3}' → {"status":"ok","tcversion_id":5} — create_version copies the platform rows to v5 via copyPlatformsTo (lib/functions/testcase.class.php:2456).
3. curl ... -X POST 'http://localhost:8082/api/testcases/?action=delete_version' -d '{"tcase_id":3,"tcversion_id":5}' → {"status":"ok",..., "versions_left":1}.
4. Bug observed (pre-fix): testcase_platforms still holds (5,1),(5,2),(5,3); SELECT id FROM tcversions WHERE id IN (4,5) → only 4; nodes_hierarchy has no id 5. `orphans` query (SELECT COUNT(*) FROM testcase_platforms WHERE tcversion_id NOT IN (SELECT id FROM tcversions)) → > 0.

Expected: deleting a version must also purge its testcase_platforms rows — no orphans accumulate.

Chain (each hop = file:line):

1. Modern BFF delete_version: api/testcases/index.php:2254 → $tcaseMgr->delete($tcaseId, $tcversionId).
2. testcase::delete() lib/functions/testcase.class.php:1659 → $this->_blind_delete($id, $version_id, $children) after _execution_delete
   • deleteAllTestCaseRelations.
3. _blind_delete (lib/functions/testcase.class.php:1834-1946) executes DELETEs on: user_assignments, testplan_tcversions, tcsteps, testcase_script_links, testcase_keywords, req_coverage, tcversions. testcase_platforms is absent from the whole list.
4. Result: the version subtree is removed but testcase_platforms rows (testcase_id + tcversion_id) pointing at the dead version survive. No other delete path touches them — the only testcase_platforms DELETEs in lib/ are deletePlatforms / deletePlatformsByLink (testcase.class.php:9858-9926), both UI-assignment-scoped, never called from a version delete. testcase_platforms has no FK constraints (verified via information_schema.KEY_COLUMN_USAGE), so nothing references or cascade-deletes it.

Why it broke now: platform rows are written since the #915 design-platform assignment work: create_new_version → copyPlatformsTo inserts them on every new version, and version delete was never taught to clean them up.

Blast radius:

• single-version deletes: modern BFF delete_version + legacy tcView_viewer delete_tc_version (doDelete with a concrete version);
• whole-TC deletes: modern BFF action=delete (api/testcases/index.php:2205)
  • legacy tcEdit doDelete → self::ALL_VERSIONS branch of _blind_delete (testcase.class.php:1842-1847);
• no other tables reference testcase_platforms (zero FK rows).

Added a single DELETE inside _blind_delete (lib/functions/testcase.class.php, right after the req_coverage delete and before the final tcversions delete, which must stay last):

$sql[]="/* $debugMsg */
        DELETE FROM {$this->tables['testcase_platforms']}
        WHERE testcase_id = {$id}
        AND tcversion_id IN ({$tcversion_list})";

Why the core was fixed instead of the API:

• $tcversion_list already holds the single version id on the single-version path and the comma-joined version list on ALL_VERSIONS, so one statement covers both delete flavors;
• testcase_id = $id scopes the purge; only versions being destroyed lose their platform rows, surviving versions keep theirs;
• fixing at core level removes the orphan risk for the modern BFF and the legacy screens (tcView_viewer, tcEdit) in both single-version and whole-TC deletes. An API-only fix in delete_version would have left action=delete and the legacy paths broken.
• Rejected alternative: API-level DELETE FROM testcase_platforms WHERE tcversion_id=<id> in delete_version — narrow, duplicates core logic, does not fix whole-TC / legacy paths.

Alternative considered but not chosen: deleting testcase_platforms before the other version-scoped deletes — unnecessary, because the table has no FK constraints; kept with the sibling DELETEs for readability.

Proof data (measured on the fixed branch):

• create_version → {"status":"ok","tcversion_id":6}; platforms (6,1),(6,2),(6,3) present.
• delete_version {tcase_id:3, tcversion_id:6} → {"status":"ok",..., "versions_left":1}; afterwards SELECT tcversion_id,platform_id FROM testcase_platforms WHERE testcase_id=3 → only 4/1, 4/2, 4/3; SELECT COUNT(*) FROM testcase_platforms WHERE tcversion_id NOT IN (SELECT id FROM tcversions) → 0.
• Whole-TC action=delete {tcase_id:3} → {"status":"ok",...}; nodes 3/4 gone, testcase_platforms orphans 0.
• Browser: Test Specification → TC Login → Create New Version (Ver. 2 shows Android/iOS/Windows) → Delete this version → confirm → Ver. 1 remains with Android/iOS/Windows intact (docs/screenshots/issue-1512-verify.png).
• php -l lib/functions/testcase.class.php → no syntax errors.

This page mirrors tmp/wiki-repo/Bugfix-Issue-1512-TestcasePlatforms-Orphans-On-DeleteVersion.md (screenshots kept in the wiki clone; docs/ keeps the code reference).