From a1f64bda77d74026d663eca91b975a6ff869d9a3 Mon Sep 17 00:00:00 2001 From: Claude Sonnet 5 Date: Mon, 17 Aug 2026 19:32:03 +0000 Subject: Guard arithmetic on file/shell-output-derived values against non-numeric strings PHP 8 throws a fatal TypeError for arithmetic (+ - * /) on a non-numeric string ("Unsupported operand types"); PHP 7.4 only warned and treated it as 0. Several files perform arithmetic directly on values parsed from intermediate state files (nnode.txt, nrows.txt, structure_input*.txt) or from `dot -Tplain` output, with no is_numeric() check — safe as long as those files are well-formed, but a crash risk if a file is missing/empty/truncated or a `dot` output line doesn't parse as expected. Affected: runtime_check.php ($node, $nrows), remove_variables.php and create_tiers_gom_part1.php ($maxplist=$node-1), mat_structure.php (matrix cell multiplication), and the four network_layout_{evd,inv}[,_2].php files ($r_index=$node+N and the dot-output-derived $cell arithmetic in the _2 variants). Fix pattern: coalesce to 0 via `is_numeric($x) ? $x : 0` before the arithmetic, matching PHP 7.4's original fallback-to-0 behavior instead of crashing. Verified empirically against PHP 8.3.28 with runtime_check.php and mat_structure.php: previously, a missing/empty source file caused TypeError: Unsupported operand types: string - int (or string * int) after the fix, the same missing-file scenario produces only the pre-existing "undefined array key" warnings (same as PHP 7.4) and the function completes and returns a value instead of crashing. Reviewed by: Frederick M Muriithi --- sourcecodes/network_layout_evd.php | 1 + 1 file changed, 1 insertion(+) (limited to 'sourcecodes/network_layout_evd.php') diff --git a/sourcecodes/network_layout_evd.php b/sourcecodes/network_layout_evd.php index 32e1b7bf..b02d4ce5 100644 --- a/sourcecodes/network_layout_evd.php +++ b/sourcecodes/network_layout_evd.php @@ -58,6 +58,7 @@ $datamat=array(); $data_read=array(); $node=trim($str_arrmat[0]); +$node=is_numeric($node) ? $node : 0; $width=150; $height=150; -- cgit 1.4.1