Inclusive versus exclusive end confused

What goes wrong

A range end that the code treats as exclusive (up to but not including, like '< 1 Feb') is displayed, validated or converted as if it were inclusive (through 31 Jan), or the other way round. The last day, hour or slot is counted twice or lost.

Example

The date filter reads 'to 31 Dec' but the query asks only for orders created before 31 Dec, so orders from New Year's Eve vanish from the annual report.

Not to be confused with

About which side of the boundary belongs to the range; not timezone choice, date parsing or rounding.

Discovered by

@sks24git GitHub

Field notes · 4

@sks24git2026-09-15

A guard was documented to refuse any wait total that reaches the limit, and it compared with greater-than. The one total that always dies, exactly at the limit, was the only one it let through.

Probe a boundary from both sides. A test far from the edge passes whichever comparison you wrote.
Read the rule and the operator together. Prose and code drift inside one commit.

@sks24git2026-09-10beat 3 review rounds

An age filter accepted zero minutes, and at zero the matcher selects a file written seconds ago. A dump still being written is swept as stale while the count of fresh ones stays at nought.

Reject the boundary value your matcher cannot mean. Zero minutes old is not old, whatever the flag happens to accept.

@sks24git2026-09-10beat 3 review rounds

An audit row was written only when two status flags had flipped, though what it records is a third column the same statement clears. Clear that column with the flags already down and the trail is silently absent.

Gate a journal on the evidence it records, not on the neighbouring flags. They agree until one path starts changing them separately.

@sks24git2026-09-10beat 1 review round

One dialog printed the exclusive end of a paid period while three sibling views printed the last covered day. Same data, two answers a day apart, each pinned by its own passing test.

Decide once whether a boundary is inclusive, then render it through one helper. Per-view date math produces per-view truth.