oh-my-posh: fix nushell with v26.0.0 (#7342)

modules/programs/oh-my-posh.nix

@@ -82,10 +82,15 @@ in
 
     programs.nushell = mkIf cfg.enableNushellIntegration {
       extraConfig = ''
-        source ${
-          pkgs.runCommand "oh-my-posh-nushell-config.nu" { } ''
-            ${lib.getExe cfg.package} init nu ${configArgument} --print >> "$out"
-          ''
+        ${
+          if lib.versionAtLeast (lib.versions.major cfg.package.version) "26" then
+            "${lib.getExe cfg.package} init nu ${configArgument}"
+          else
+            ''source ${
+              pkgs.runCommand "oh-my-posh-nushell-config.nu" { } ''
+                ${lib.getExe cfg.package} init nu ${configArgument} --print >> "$out"
+              ''
+            }''
         }
       '';
     };

tests/modules/programs/oh-my-posh/nushell.nix

@@ -28,8 +28,18 @@
     in
     ''
       assertFileExists "${configFile}"
-      assertFileRegex \
-        "${configFile}" \
-        'source /nix/store/[^/]*-oh-my-posh-nushell-config.nu'
+      ${
+        if (lib.versionAtLeast (lib.versions.major config.programs.oh-my-posh.package.version) "26") then
+          ''
+            assertFileContains \
+                    "${configFile}" \
+                    "/bin/oh-my-posh init nu --config"''
+        else
+
+          ''
+            assertFileRegex \
+                    "${configFile}" \
+                    "source /nix/store/[^/]*-oh-my-posh-nushell-config.nu"''
+      }
     '';
 }