ssh: install an ssh client

Fixes #3667

modules/misc/news.nix

@@ -103,7 +103,7 @@ in
       entries = mkOption {
         internal = true;
         type = types.listOf entryModule;
-        default = [];
+        default = [ ];
         description = "News entries.";
       };
     };
@@ -1023,6 +1023,16 @@ in
           A new module is available: 'programs.fuzzel'.
         '';
       }
+
+      {
+        time = "2023-05-13T14:34:21+00:00";
+        condition = config.programs.ssh.enable;
+        message = ''
+          The module 'programs.ssh' now installs an SSH client. The installed
+          client is controlled by the 'programs.ssh.package` option, which
+          defaults to 'pkgs.openssh'.
+        '';
+      }
     ];
   };
 }

modules/programs/ssh.nix

@@ -361,6 +361,8 @@ in
   options.programs.ssh = {
     enable = mkEnableOption "SSH client configuration";
 
+    package = mkPackageOption pkgs "openssh" { };
+
     forwardAgent = mkOption {
       default = false;
       type = types.bool;
@@ -525,6 +527,8 @@ in
       }
     ];
 
+    home.packages = [ cfg.package ];
+
     home.file.".ssh/config".text =
       let
         sortedMatchBlocks = hm.dag.topoSort cfg.matchBlocks;

tests/modules/programs/ssh/default-config.nix

@@ -6,6 +6,8 @@ with lib;
   config = {
     programs.ssh = { enable = true; };
 
+    test.stubs.openssh = { };
+
     home.file.assertions.text = builtins.toJSON
       (map (a: a.message) (filter (a: !a.assertion) config.assertions));
 

tests/modules/programs/ssh/forwards-dynamic-bind-path-with-port-asserts.nix

@@ -17,6 +17,8 @@ with lib;
       };
     };
 
+    test.stubs.openssh = { };
+
     test.asserts.assertions.expected = [ "Forwarded paths cannot have ports." ];
   };
 }

tests/modules/programs/ssh/forwards-dynamic-valid-bind-no-asserts.nix

@@ -27,6 +27,8 @@ with lib;
     home.file.result.text = builtins.toJSON
       (map (a: a.message) (filter (a: !a.assertion) config.assertions));
 
+    test.stubs.openssh = { };
+
     nmt.script = ''
       assertFileExists home-files/.ssh/config
       assertFileContent \

tests/modules/programs/ssh/forwards-local-bind-path-with-port-asserts.nix

@@ -21,6 +21,8 @@ with lib;
       };
     };
 
+    test.stubs.openssh = { };
+
     test.asserts.assertions.expected = [ "Forwarded paths cannot have ports." ];
   };
 }

tests/modules/programs/ssh/forwards-local-host-path-with-port-asserts.nix

@@ -21,6 +21,8 @@ with lib;
       };
     };
 
+    test.stubs.openssh = { };
+
     test.asserts.assertions.expected = [ "Forwarded paths cannot have ports." ];
   };
 }

tests/modules/programs/ssh/forwards-remote-bind-path-with-port-asserts.nix

@@ -21,6 +21,8 @@ with lib;
       };
     };
 
+    test.stubs.openssh = { };
+
     test.asserts.assertions.expected = [ "Forwarded paths cannot have ports." ];
   };
 }

tests/modules/programs/ssh/forwards-remote-host-path-with-port-asserts.nix

@@ -21,6 +21,8 @@ with lib;
       };
     };
 
+    test.stubs.openssh = { };
+
     test.asserts.assertions.expected = [ "Forwarded paths cannot have ports." ];
   };
 }

tests/modules/programs/ssh/includes.nix

@@ -7,6 +7,8 @@
       includes = [ "config.d/*" "other/dir" ];
     };
 
+    test.stubs.openssh = { };
+
     nmt.script = ''
       assertFileExists home-files/.ssh/config
       assertFileContains home-files/.ssh/config "Include config.d/* other/dir"

tests/modules/programs/ssh/match-blocks-attrs.nix

@@ -51,6 +51,8 @@ with lib;
     home.file.assertions.text = builtins.toJSON
       (map (a: a.message) (filter (a: !a.assertion) config.assertions));
 
+    test.stubs.openssh = { };
+
     nmt.script = ''
       assertFileExists home-files/.ssh/config
       assertFileContent \

tests/modules/programs/ssh/match-blocks-match-and-hosts.nix

@@ -21,6 +21,8 @@ with lib;
     home.file.assertions.text = builtins.toJSON
       (map (a: a.message) (filter (a: !a.assertion) config.assertions));
 
+    test.stubs.openssh = { };
+
     nmt.script = ''
       assertFileExists home-files/.ssh/config
       assertFileContent \