From b0a5b92fac498c2aa6fa92853f9d2df6b51bd697 Mon Sep 17 00:00:00 2001
From: EdiWeeks <121399761+EdiWeeks@users.noreply.github.com>
Date: Tue, 5 May 2026 12:40:35 +0100
Subject: [PATCH 1/2] fix: handle BC null-date sentinel on project header dates

The project header used a local formatDate that wrapped `new Date(...).toLocaleDateString('en-GB', ...)`. BC returns "0001-01-01" as the
null-date sentinel for projects with no start/end set. The empty-string
guard didn't catch it, so toLocaleDateString rendered the value as
"31 Dec 1" (timezone shift in negative-UTC zones flips the day).

- Add a sentinel guard for any "0001-..." date string.
- Use the shared formatDate util + DATE_FORMAT_FULL ("d MMM yyyy"), which
  goes through date-fns parseISO and avoids the timezone shift.

Fixes #199

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 src/components/projects/ProjectHeader.tsx | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/src/components/projects/ProjectHeader.tsx b/src/components/projects/ProjectHeader.tsx
index 2ce9db5..aa40781 100644
--- a/src/components/projects/ProjectHeader.tsx
+++ b/src/components/projects/ProjectHeader.tsx
@@ -15,22 +15,22 @@ import {
 } from '@heroicons/react/24/outline';
 import { useProjectDetailsStore } from '@/hooks/useProjectDetailsStore';
 import { useCompanyStore } from '@/hooks';
-import { getBCJobUrl } from '@/utils';
-import { cn } from '@/utils';
+import { cn, DATE_FORMAT_FULL, formatDate as formatDateUtil, getBCJobUrl } from '@/utils';
 import type { BillingMode } from '@/services/bc/projectDetailsService';
 
 /**
- * Format a date string for display (e.g., "15 Jan 2025")
+ * Format a date string for display (e.g., "15 Jan 2025").
+ *
+ * Treats BC's null-date sentinel ("0001-..." — typically "0001-01-01") as
+ * unspecified. The sentinel arrives as a non-empty ISO string, so the
+ * empty-check alone misses it and `new Date()` would render it as a year-1
+ * garbage date (a timezone shift can also flip it to "31 Dec 1" in negative
+ * UTC zones).
  */
 function formatDate(dateStr?: string): string {
-  if (!dateStr) return 'Unspecified';
+  if (!dateStr || dateStr.startsWith('0001-')) return 'Unspecified';
   try {
-    const date = new Date(dateStr);
-    return date.toLocaleDateString('en-GB', {
-      day: 'numeric',
-      month: 'short',
-      year: 'numeric',
-    });
+    return formatDateUtil(dateStr, DATE_FORMAT_FULL);
   } catch {
     return 'Unspecified';
   }

From 3f6adae37f478763b95cee98a5ef2ea58bbc82e9 Mon Sep 17 00:00:00 2001
From: EdiWeeks <121399761+EdiWeeks@users.noreply.github.com>
Date: Tue, 5 May 2026 12:46:30 +0100
Subject: [PATCH 2/2] docs: reword formatDate comment to lead with observed
 symptom
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Per Copilot review on PR #200 — describe the actual "31 Dec 1" output
(timezone-shifted day + unpadded year) rather than the abstract "year-1
garbage date" framing, which made the symptom less obvious to readers.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 src/components/projects/ProjectHeader.tsx | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/components/projects/ProjectHeader.tsx b/src/components/projects/ProjectHeader.tsx
index aa40781..eb7e1f7 100644
--- a/src/components/projects/ProjectHeader.tsx
+++ b/src/components/projects/ProjectHeader.tsx
@@ -23,9 +23,9 @@ import type { BillingMode } from '@/services/bc/projectDetailsService';
  *
  * Treats BC's null-date sentinel ("0001-..." — typically "0001-01-01") as
  * unspecified. The sentinel arrives as a non-empty ISO string, so the
- * empty-check alone misses it and `new Date()` would render it as a year-1
- * garbage date (a timezone shift can also flip it to "31 Dec 1" in negative
- * UTC zones).
+ * empty-check alone misses it; `new Date(...).toLocaleDateString` then
+ * renders it as e.g. "31 Dec 1" — the timezone shift in negative-UTC zones
+ * flips the calendar day, and the year prints unpadded as "1".
  */
 function formatDate(dateStr?: string): string {
   if (!dateStr || dateStr.startsWith('0001-')) return 'Unspecified';