fix(php-src): assert php_gcvt's unported arguments up front

php_gcvt only ports the ndigit < 0 (dtoa mode 0) path and hardcodes the
'.'/'E' separators of its sole caller into the placement logic, but it
accepted any argument and silently produced a wrong string for the rest.
Assert the supported combination instead, and turn the mode 2 bail-out
into unreachable! now that the assert rules it out.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

0 files changed, 0 insertions, 0 deletions