Modernization of Test Plan Milestones (lib/plan/planMilestonesView.php + lib/plan/planMilestonesEdit.php + planMilestonesCommands.class.php) — GitHub issue #647.

The legacy Smarty screens are replaced by a standalone Dashio page (gui/templates/plans/planMilestones.html) backed by a plain-PHP REST BFF (api/milestones/index.php), following the same pattern as the other modernized screens. The aside menu entry Test Case Execution → Milestones now points to the new HTML screen (switched in lib/functions/common.php, both the milestonesView link and the old mileView launcher entry).

Feature	Legacy behavior	Modern implementation
List milestones of current test plan (ordered by target date)	testplan_planning required (checkGUISecurityClearance rightsAnd)	GET /api/milestones/index.php/list?tplan_id=N (403 otherwise); aside visibility still gated by testplan_milestone_overview
Create milestone (name, target date, optional start date, priority %)	edit form → do_create; duplicate name per plan; valid dates; target not in past; target ≥ start; % 0–100	POST …/create?tplan_id=N returning 400 + stable error codes for every validation branch
Edit milestone in modal	name click → edit / do_update	row-name button opens prefilled modal → PUT …/update/{id}; past-target check only when date changed (BUGID parity)
Delete milestone with confirm dialog	delete icon → delete_confirmation() → doDelete	trash icon → Bootstrap confirm modal → DELETE …/delete/{id}
Priority columns High/Medium/Low vs single % column	depends on project option testPriorityEnabled; when disabled only medium is editable (hidden 0 fields)	same layout switch driven by BFF-provided flag; modal swaps 3 inputs for one input
Live "Status of Milestones" report	tlTestPlanMetrics::getMilestonesMetrics() table: achieved % per priority vs expected %, red/green coloring, overall %	identical computation reused server-side; client renders green/red badges + (done/total) counters + expected %
Execution window semantics	only executions within [start_date, target_date] count	inherited from the shared metrics class (verified live: execution before start date is excluded)
Audit trail	audit_milestone_created/saved/deleted	identical events written by the BFF

Edit modal (prefilled; unique-name hint, target/start dates, A/B/C percentage inputs):

Delete confirmation dialog:

• Everything: testplan_planning — exactly what the legacy controller enforces on planMilestonesView.php / planMilestonesEdit.php.
• The aside menu shows the entry only for users with testplan_milestone_overview, but the screen/BFF additionally require testplan_planning (a read-only user without it gets HTTP 403 on every route).

• Error messages are stable codes (milestone_name_already_exists, warning_invalid_date, warning_milestone_date, warning_target_before_start, warning_empty_milestone_name, warning_invalid_percentage) localized client-side via the ms.* i18n keys present in all 10 locale bundles.
• Percentage mapping quirk preserved: in legacy the edit-form field labeled High priority % posts as low_priority_tcases, while reads alias DB column a as high_percentage. The modern BFF maps request values so the user-visible round-trip matches legacy exactly (enter X under High → read back X under High).
• Dates are stored ISO YYYY-MM-DD; empty start date persists as 0000-00-00 (BUGID 3907 parity).
• Plans without builds render no metrics section (getMilestonesMetrics returns [], cf. issue #634 fix).
• Test suite: tmp/TLU_Test_Cases.md Suite 647 — 18/18 PASS.
• Event history (added 2026-09-07, Refs #1149): the edit modal now shows a Show event history button (hidden while creating a new milestone) for users holding mgt_view_events. It mirrors the legacy planMilestonesEdit.tpl showEventHistoryFor(id,'milestones') icon and the platformsView.html pattern: hidden #eventhistory form posts object_id/object_type=milestones to /gui/templates/eventviewer/eventviewer.html. The BFF /list exposes rights.canViewEvents; new ms.showEventHistory key added to all 10 locale bundles. See GitHub issue #1148/#1149.

• SCREEN-COMPARE (2026-09-07, Refs #1148): re-verified against legacy lib/plan/planMilestonesView.php/planMilestonesEdit.php on seeded project MS Demo Project (plan MS Plan One, milestones MS Alpha/Beta/Gamma, 4 TCs + executions for live metrics, no-rights role-3 user msnorg). Confirmed full parity (list + "Status of Milestones" achieved-vs-expected report, create/edit/ delete + audit CREATE/SAVE/DELETE rows, duplicate-name/past-date/invalid-%/ empty-name validation, testplan_planning 403). Only gap was the dropped event-history icon → fixed (#1149) and browser-verified (opens eventviewer filtered milestones #4, shows the audit SAVE trail). Test suite: tmp/TLU_Test_Cases.md Suite 1148 — 11/11 PASS.

• Legacy grid DataTables contract (added 2026-09-27, Fixes #1650): the legacy screen lib/plan/planMilestonesView.php → gui/templates/dashio/plan/planMilestonesView.tpl already included DataTables.inc.tpl with DataTablesSelector="#item_view" (tpl:36), but its table was <table class="common" width="100%"> with no id and no <thead> — so $('#item_view').DataTable(config) was a silent no-op on an empty jQuery set (no console error). Measured before the fix: #item_view = 0, no .dataTables_length / .dataTables_filter / .dataTables_info, thead count 0, while the lengthMenu/stateSave config was emitted into the page. The [planMilestonesView] config added by #1594 (item_view_table="table table-bordered", item_view_thead="thead-dark", pagination_length=20) had no consumer. Fixed by porting the grid to the same contract the sibling Dashio list screens use (buildView.tpl:86, planView.tpl:96, rolesView.tpl:73): <table class="{#item_view_table#}" id="item_view">, header row in <thead class="{#item_view_thead#}">, data rows in <tbody>, and the Delete action column marked data-orderable="false" class="icon_cell" so it stays out of sorting and out of the global search index. The separate "Milestones Report" (simple_tableruler) table is deliberately untouched. After the fix (both project variants, testPriorityEnabled 1 → 7 columns and 0 → 5 columns): #item_view = 1 with class table table-bordered dataTable no-footer, thead thead-dark, #item_view_wrapper present, page-length menu 20/40/60/All, .dataTables_info "Showing 1 to 3 of 3 entries", search filters, Name sorting asc/desc, stateSave persists the page length across reloads, delete delete_confirmation() handlers and planMilestonesEdit.php links unchanged. The modernized screen gui/templates/plans/planMilestones.html was not affected — it already initialises DataTables on #msTable / #reportTable; this gap was confined to the legacy template that is still shipped (cf. the open "Delete legacy …" cleanup tasks). Test suite: tmp/TLU_Test_Cases.md Suite 1650 — 22/22 PASS; Event Viewer 0 new ERROR/WARNING. See GitHub issue #1650.