From: Lennart Poettering <lennart@poettering.net>
Date: Fri, 12 Nov 2021 09:17:07 +0000 (+0100)
Subject: docs: clarify the assumption on numeric values of JSON parsers we make
X-Git-Tag: v250-rc1~204
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=14efbfd96d67800e55137f89ec7a09d81049d176;p=thirdparty%2Fsystemd.git

docs: clarify the assumption on numeric values of JSON parsers we make

Prompted by:

https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/message/BOBD6KVTXPR6K5ANAX6LIJLKNSGXCR3B/
---

diff --git a/docs/COREDUMP_PACKAGE_METADATA.md b/docs/COREDUMP_PACKAGE_METADATA.md
index e34abbd1478..705d5d695aa 100644
--- a/docs/COREDUMP_PACKAGE_METADATA.md
+++ b/docs/COREDUMP_PACKAGE_METADATA.md
@@ -67,6 +67,16 @@ Value: a JSON string with the structure described below
 }
 ```
 
+When it comes to JSON numbers, this specification assumes that JSON parsers
+processing this information are capable of reproducing the full signed 53bit
+integer range (i.e. -2⁵³+1…+2⁵³-1) as well as the full 64bit IEEE floating
+point number range losslessly (with the exception of NaN/-inf/+inf, since JSON
+cannot encode that), as per recommendations of
+[RFC8259](https://datatracker.ietf.org/doc/html/rfc8259#page-8). Fields in
+these JSON objects are thus permitted to encode numeric values from these
+ranges as JSON numbers, and should not use numeric values not covered by these
+types and ranges.
+
 A reference implementations of a [build-time tool is provided](https://github.com/systemd/package-notes)
 and can be used to generate a linker script, which can then be used at build time via
 ```LDFLAGS="-Wl,-T,/path/to/generated/script"``` to include the note in the binary.