From 4e401b76c7c0f3f902b7a05d8bfaab8ffa700b0c Mon Sep 17 00:00:00 2001 From: Ewan Young Date: Thu, 11 Jun 2026 22:32:09 +0800 Subject: [PATCH] seg: Fix seg_out() to preserve the upper boundary's certainty indicator When printing the upper boundary of a seg interval, seg_out() decided whether to emit the certainty indicator ('<', '>' or '~') by testing the upper indicator (u_ext) for '<' and '>', but mistakenly tested the lower indicator (l_ext) for '~'. This is a copy-and-paste slip from the symmetric code that prints the lower boundary a few lines above. The consequences for valid input were: * A '~' on the upper boundary was dropped on output, e.g. '1.5 .. ~2.5'::seg printed as '1.5 .. 2.5'. * When the lower boundary carried '~' but the upper boundary had no indicator, the wrong test matched and sprintf(p, "%c", seg->u_ext) wrote a NUL byte (u_ext == '\0'), which truncated the result string and silently lost the entire upper boundary, e.g. '~6.5 .. 8.5'::seg printed as '~6.5 .. '. Certainty indicators are documented to be preserved on output (they are ignored by the operators, but kept as comments), so this broke the input/output round-trip for the affected values. The bug has existed since seg was added. It went unnoticed because the existing regression tests only exercised certainty indicators on single-point segs, which are printed by a different branch of seg_out(). Add tests that place indicators on both boundaries of an interval. --- contrib/seg/expected/seg.out | 45 ++++++++++++++++++++++++++++++++++++ contrib/seg/seg.c | 2 +- contrib/seg/sql/seg.sql | 11 +++++++++ 3 files changed, 57 insertions(+), 1 deletion(-) diff --git a/contrib/seg/expected/seg.out b/contrib/seg/expected/seg.out index cd21139b5a7..dd30156dfe8 100644 --- a/contrib/seg/expected/seg.out +++ b/contrib/seg/expected/seg.out @@ -300,6 +300,51 @@ SELECT '> 6.5'::seg AS seg; >6.5 (1 row) +-- Certainty indicators on interval boundaries must be preserved on output. +-- (They are ignored by operators, but are kept as comments; in particular the +-- indicator on the upper boundary must round-trip.) +SELECT '~1.5 .. 2.5'::seg AS seg; + seg +------------- + ~1.5 .. 2.5 +(1 row) + +SELECT '1.5 .. ~2.5'::seg AS seg; + seg +------------- + 1.5 .. ~2.5 +(1 row) + +SELECT '~1.5 .. ~2.5'::seg AS seg; + seg +-------------- + ~1.5 .. ~2.5 +(1 row) + +SELECT '<1.5 .. 2.5'::seg AS seg; + seg +------------- + <1.5 .. 2.5 +(1 row) + +SELECT '1.5 .. <2.5'::seg AS seg; + seg +------------- + 1.5 .. <2.5 +(1 row) + +SELECT '>1.5 .. 2.5'::seg AS seg; + seg +------------- + >1.5 .. 2.5 +(1 row) + +SELECT '1.5 .. >2.5'::seg AS seg; + seg +------------- + 1.5 .. >2.5 +(1 row) + -- Open intervals SELECT '0..'::seg AS seg; seg diff --git a/contrib/seg/seg.c b/contrib/seg/seg.c index fcded0245aa..c7b374825f8 100644 --- a/contrib/seg/seg.c +++ b/contrib/seg/seg.c @@ -152,7 +152,7 @@ seg_out(PG_FUNCTION_ARGS) { /* print the upper boundary if exists */ p += sprintf(p, " "); - if (seg->u_ext == '>' || seg->u_ext == '<' || seg->l_ext == '~') + if (seg->u_ext == '>' || seg->u_ext == '<' || seg->u_ext == '~') p += sprintf(p, "%c", seg->u_ext); p += restore(p, seg->upper, seg->u_sigd); } diff --git a/contrib/seg/sql/seg.sql b/contrib/seg/sql/seg.sql index c30f1f6bef1..4fe1bb6d851 100644 --- a/contrib/seg/sql/seg.sql +++ b/contrib/seg/sql/seg.sql @@ -71,6 +71,17 @@ SELECT '~ 6.5'::seg AS seg; SELECT '< 6.5'::seg AS seg; SELECT '> 6.5'::seg AS seg; +-- Certainty indicators on interval boundaries must be preserved on output. +-- (They are ignored by operators, but are kept as comments; in particular the +-- indicator on the upper boundary must round-trip.) +SELECT '~1.5 .. 2.5'::seg AS seg; +SELECT '1.5 .. ~2.5'::seg AS seg; +SELECT '~1.5 .. ~2.5'::seg AS seg; +SELECT '<1.5 .. 2.5'::seg AS seg; +SELECT '1.5 .. <2.5'::seg AS seg; +SELECT '>1.5 .. 2.5'::seg AS seg; +SELECT '1.5 .. >2.5'::seg AS seg; + -- Open intervals SELECT '0..'::seg AS seg; SELECT '0...'::seg AS seg; -- 2.47.3