lib.strings: fix negative number handling for `toInt` and `toIntBase10`

The previous version would be unstable due to an input validation regex
not expecting a '-' in front of the number.

1 files changed, 7 insertions, 6 deletions

diff --git a/lib/strings.nix b/lib/strings.nix
index b5f5a4d9060..a5c3965f8f1 100644
--- a/lib/strings.nix
+++ b/lib/strings.nix
@@ -807,9 +807,9 @@ rec {
   */
   toInt = str:
     let
-      # RegEx: Match any leading whitespace, then any digits, and finally match any trailing
-      # whitespace.
-      strippedInput = match "[[:space:]]*([[:digit:]]+)[[:space:]]*" str;
+      # RegEx: Match any leading whitespace, possibly a '-', one or more digits,
+      # and finally match any trailing whitespace.
+      strippedInput = match "[[:space:]]*(-?[[:digit:]]+)[[:space:]]*" str;
 
       # RegEx: Match a leading '0' then one or more digits.
       isLeadingZero = match "0[[:digit:]]+" (head strippedInput) == [];
@@ -858,9 +858,10 @@ rec {
   */
   toIntBase10 = str:
     let
-      # RegEx: Match any leading whitespace, then match any zero padding, capture any remaining
-      # digits after that, and finally match any trailing whitespace.
-      strippedInput = match "[[:space:]]*0*([[:digit:]]+)[[:space:]]*" str;
+      # RegEx: Match any leading whitespace, then match any zero padding,
+      # capture possibly a '-' followed by one or more digits,
+      # and finally match any trailing whitespace.
+      strippedInput = match "[[:space:]]*0*(-?[[:digit:]]+)[[:space:]]*" str;
 
       # RegEx: Match at least one '0'.
       isZero = match "0+" (head strippedInput) == [];