Merge pull request #60406 from JohnAZoidberg/remove-isnull

treewide: Remove usage of isNull

lib/generators.nix

@@ -178,7 +178,7 @@ rec {
   toPlist = {}: v: let
     isFloat = builtins.isFloat or (x: false);
     expr = ind: x:  with builtins;
-      if isNull x   then "" else
+      if x == null  then "" else
       if isBool x   then bool ind x else
       if isInt x    then int ind x else
       if isString x then str ind x else

lib/sources.nix

@@ -83,7 +83,7 @@ rec {
                  # Sometimes git stores the commitId directly in the file but
                  # sometimes it stores something like: «ref: refs/heads/branch-name»
                  matchRef    = match "^ref: (.*)$" fileContent;
-             in if   isNull matchRef
+             in if   matchRef == null
                 then fileContent
                 else readCommitFromFile (lib.head matchRef) path
            # Sometimes, the file isn't there at all and has been packed away in the
@@ -92,7 +92,7 @@ rec {
            then
              let fileContent = readFile packedRefsName;
                  matchRef    = match (".*\n([^\n ]*) " + file + "\n.*") fileContent;
-             in if   isNull matchRef
+             in if   matchRef == null
                 then throw ("Could not find " + file + " in " + packedRefsName)
                 else lib.head matchRef
            else throw ("Not a .git directory: " + path);

lib/trivial.nix

@@ -112,7 +112,7 @@ rec {
     # Function to call
     f:
     # Argument to check for null before passing it to `f`
-    a: if isNull a then a else f a;
+    a: if a == null then a else f a;
 
   # Pull in some builtins not included elsewhere.
   inherit (builtins)