feat(mail-overview): track the notified revision

Stores the database UUID beside the revision, because notmuch
revisions only compare within one database and a rebuild restarts
the counter. Missing, corrupt or mismatched state reports nothing,
which the caller treats as seed-silently: with no floor, lastmod:0..
matches every unread message and startup becomes a wall of popups.

1 files changed, 25 insertions, 0 deletions

diff --git a/mail-overview/test-mail-notify.sh b/mail-overview/test-mail-notify.sh
index fccf4b3..95e971d 100755
--- a/mail-overview/test-mail-notify.sh
+++ b/mail-overview/test-mail-notify.sh
@@ -111,5 +111,30 @@ check "malformed json yields an empty body rather than an error" \
     "" \
     "$(build_body 'not json at all' 1 2>/dev/null)"
 
+# A scratch state file, removed at exit. Never the real one: that is the
+# user's live notification position, and a test must not move it.
+tmpstate="$(mktemp)"
+trap 'rm -f "$tmpstate"' EXIT
+STATE="$tmpstate"
+
+rm -f "$tmpstate"
+check "a missing state file reports no previous revision" \
+    "" "$(read_prev_rev "uuid-a")"
+
+write_state "uuid-a" 500
+check "a revision written is a revision read back" \
+    "500" "$(read_prev_rev "uuid-a")"
+
+check "a different database UUID discards the revision" \
+    "" "$(read_prev_rev "uuid-b")"
+
+printf 'garbage not a state file\n' > "$tmpstate"
+check "an unparseable state file reports no previous revision" \
+    "" "$(read_prev_rev "uuid-a")"
+
+write_state "uuid-a" 600
+check "a rewrite replaces rather than appends" \
+    "1" "$(wc -l < "$tmpstate")"
+
 printf '\n%d passed, %d failed\n' "$pass" "$fail"
 [[ "$fail" -eq 0 ]]