URL query / duplicate key / array convention

Separate URL query duplicates and array meaning

Review duplicate query keys, bracket arrays, plus signs, order and fragment boundaries with synthetic cases. User URLs are never accepted; save a local review note instead.

Review decisions Save review note

Five URL query boundaries

Same-name query keys are handled differently by servers and libraries. Record array notation, decoding, order and fragments separately.

same key ≠ one value / query → array → verify

Axis	Review
duplicate	Do not silently collapse duplicate query keys to the last value.
bracket	`items[]=a` is a convention, not a universal specification.
plus	Separate plus-as-space from a literal plus sign.
order	Keep order when a server gives it meaning.
fragment	A fragment is separate from the query and is not sent to a server.

Safe review order

Record duplicate keys and order in a synthetic query.
State the interpretation of brackets and plus signs.
Separate the fragment boundary before handing values off.
Approve the local note before returning to a real URL.

This page never parses user URLs. It uses synthetic cases only and performs no external request, storage or URL rewrite.

Six synthetic cases

case	result
`duplicate-keys`	Preserve duplicate values
`bracket-array`	Bracket convention
`plus-decoding`	Plus boundary
`order-preserved`	Keep order
`fragment-boundary`	Fragment is separate
`local-note`	Local handoff