Add "nix profile rollback" command

2 files changed, 59 insertions, 0 deletions

diff --git a/src/nix/profile-rollback.md b/src/nix/profile-rollback.md
new file mode 100644
index 000000000..fccdbb10e
--- /dev/null
+++ b/src/nix/profile-rollback.md
@@ -0,0 +1,26 @@
+R""(
+
+# Examples
+
+* Roll back your default profile to the previous version:
+
+  ```console
+  # nix profile rollback
+  switching from generation 519 to 518
+  ```
+
+* Switch your default profile to version 510:
+
+  ```console
+  # nix profile rollback --to 510
+  switching from generation 518 to 510
+  ```
+
+# Description
+
+This command switches a profile to the most recent version older
+than the currently active version, or if `--to` *N* is given, to
+version *N* of the profile. To see the available versions of a
+profile, use `nix profile history`.
+
+)""
diff --git a/src/nix/profile.cc b/src/nix/profile.cc
index 8cef6d0b6..4c4a9bff4 100644
--- a/src/nix/profile.cc
+++ b/src/nix/profile.cc
@@ -543,6 +543,38 @@ struct CmdProfileHistory : virtual StoreCommand, EvalCommand, MixDefaultProfile
     }
 };
 
+struct CmdProfileRollback : virtual StoreCommand, MixDefaultProfile, MixDryRun
+{
+    std::optional<GenerationNumber> version;
+
+    CmdProfileRollback()
+    {
+        addFlag({
+            .longName = "to",
+            .description = "The profile version to roll back to.",
+            .labels = {"version"},
+            .handler = {&version},
+        });
+    }
+
+    std::string description() override
+    {
+        return "roll back to the previous version or a specified version of this profile";
+    }
+
+    std::string doc() override
+    {
+        return
+          #include "profile-rollback.md"
+          ;
+    }
+
+    void run(ref<Store> store) override
+    {
+        switchGeneration(*profile, version, dryRun);
+    }
+};
+
 struct CmdProfile : NixMultiCommand
 {
     CmdProfile()
@@ -553,6 +585,7 @@ struct CmdProfile : NixMultiCommand
               {"list", []() { return make_ref<CmdProfileList>(); }},
               {"diff-closures", []() { return make_ref<CmdProfileDiffClosures>(); }},
               {"history", []() { return make_ref<CmdProfileHistory>(); }},
+              {"rollback", []() { return make_ref<CmdProfileRollback>(); }},
           })
     { }