Avoid losing info when formatting integers

* doc/lispref/numbers.texi (Integer Basics): Clarify that
out-of-range integers are treated as floating point only when the
integers are decimal.
* etc/NEWS: Mention changes.
* src/editfns.c (styled_format): Use %.0f when formatting %d or %i
values outside machine integer range, to avoid losing info.
Signal an error for %o or %x values that are too large to be
formatted, to avoid losing info.

1 files changed, 7 insertions, 0 deletions

diff --git a/etc/NEWS b/etc/NEWS
index 07f6d04a740..14926ba2e3b 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -302,6 +302,10 @@ as new-style, bind the new variable 'force-new-style-backquotes' to t.
 'cl-struct-define' whose name clashes with a builtin type (e.g.,
 'integer' or 'hash-table') now signals an error.
 
+** When formatting a floating-point number as an octal or hexadecimal
+integer, Emacs now signals an error if the number is too large for the
+implementation to format (Bug#30408).
+
 
 * Lisp Changes in Emacs 27.1
 
@@ -343,6 +347,9 @@ remote systems, which support this check.
 If the optional third argument is non-nil, 'make-string' will produce
 a multibyte string even if its second argument is an ASCII character.
 
+** (format "%d" X) no longer mishandles a floating-point number X that
+does not fit in a machine integer (Bug#30408).
+
 ** New JSON parsing and serialization functions 'json-serialize',
 'json-insert', 'json-parse-string', and 'json-parse-buffer'.  These
 are implemented in C using the Jansson library.