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help / color / mirror / Atom feedFrom: Andrew Dunstan <andrew@dunslane.net>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: Fix incremental JSON parser numeric token reassembly across chun
Date: Fri, 10 Apr 2026 14:21:48 +0000
Message-ID: <E1wBCk0-000JOZ-0i@gemulon.postgresql.org> (raw)
Fix incremental JSON parser numeric token reassembly across chunks.
When the incremental JSON parser splits a numeric token across chunk
boundaries, it accumulates continuation characters into the partial
token buffer. The accumulator's switch statement unconditionally
accepted '+', '-', '.', 'e', and 'E' as valid numeric continuations
regardless of position, which violated JSON number grammar
(-? int [frac] [exp]). For example, input "4-" fed in single-byte
chunks would accumulate the '-' into the numeric token, producing an
invalid token that later triggered an assertion failure during
re-lexing.
Fix by tracking parser state (seen_dot, seen_exp, prev character)
across the existing partial token and incoming bytes, so that each
character class is accepted only in its grammatically valid position.
Backpatch-through: 17
Branch
------
REL_18_STABLE
Details
-------
https://git.postgresql.org/pg/commitdiff/3e4955630292a7eb38f5fb3c6c5685623088ffd1
Modified Files
--------------
src/common/jsonapi.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++------
1 file changed, 55 insertions(+), 6 deletions(-)
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To: pgsql-committers@postgresql.org
Cc: andrew@dunslane.net, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Fix incremental JSON parser numeric token reassembly across chun
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