sign: Implement the jj sign command

Cannot make it accept multiple revisions easily, that'd have to be done
with a rebaser

cli/src/commands/mod.rs

@@ -45,6 +45,7 @@ mod restore;
 mod root;
 mod run;
 mod show;
+mod sign;
 mod simplify_parents;
 mod sparse;
 mod split;
@@ -128,6 +129,7 @@ enum Command {
     // TODO: Flesh out.
     Run(run::RunArgs),
     Show(show::ShowArgs),
+    Sign(sign::SignArgs),
     SimplifyParents(simplify_parents::SimplifyParentsArgs),
     #[command(subcommand)]
     Sparse(sparse::SparseCommand),
@@ -207,6 +209,7 @@ pub fn run_command(ui: &mut Ui, command_helper: &CommandHelper) -> Result<(), Co
             simplify_parents::cmd_simplify_parents(ui, command_helper, args)
         }
         Command::Show(args) => show::cmd_show(ui, command_helper, args),
+        Command::Sign(args) => sign::cmd_sign(ui, command_helper, args),
         Command::Sparse(args) => sparse::cmd_sparse(ui, command_helper, args),
         Command::Split(args) => split::cmd_split(ui, command_helper, args),
         Command::Squash(args) => squash::cmd_squash(ui, command_helper, args),

cli/src/commands/sign.rs

@@ -0,0 +1,43 @@
+// Copyright 2023 The Jujutsu Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use crate::cli_util::CommandHelper;
+use crate::cli_util::RevisionArg;
+use crate::command_error::CommandError;
+use crate::ui::Ui;
+
+/// Cryptographically sign a revision
+#[derive(clap::Args, Clone, Debug)]
+pub struct SignArgs {
+    /// What key to use, depends on the configured signing backend.
+    #[arg()]
+    key: Option<String>,
+    /// What revision to sign
+    #[arg(long, short, default_value = "@")]
+    revisions: Vec<RevisionArg>,
+    /// Sign a commit that is not authored by you or was already signed.
+    #[arg(long, short)]
+    force: bool,
+    /// Drop the signature, explicitly "un-signing" the commit.
+    #[arg(long, short = 'D', conflicts_with = "force")]
+    drop: bool,
+}
+
+pub fn cmd_sign(
+    _ui: &mut Ui,
+    _command: &CommandHelper,
+    _args: &SignArgs,
+) -> Result<(), CommandError> {
+    todo!()
+}

cli/tests/cli-reference@.md.snap

@@ -1,6 +1,7 @@
 ---
 source: cli/tests/test_generate_md_cli_help.rs
 description: "AUTO-GENERATED FILE, DO NOT EDIT. This cli reference is generated by a test as an `insta` snapshot. MkDocs includes this snapshot from docs/cli-reference.md."
+snapshot_kind: text
 ---
 <!-- BEGIN MARKDOWN-->
 
@@ -79,6 +80,7 @@ This document contains the help content for the `jj` command-line program.
 * [`jj restore`↴](#jj-restore)
 * [`jj root`↴](#jj-root)
 * [`jj show`↴](#jj-show)
+* [`jj sign`↴](#jj-sign)
 * [`jj simplify-parents`↴](#jj-simplify-parents)
 * [`jj sparse`↴](#jj-sparse)
 * [`jj sparse edit`↴](#jj-sparse-edit)
@@ -149,6 +151,7 @@ To get started, see the tutorial at https://jj-vcs.github.io/jj/latest/tutorial/
 * `restore` — Restore paths from another revision
 * `root` — Show the current workspace root directory
 * `show` — Show commit description and changes in a revision
+* `sign` — Cryptographically sign a revision
 * `simplify-parents` — Simplify parent edges for the specified revision(s)
 * `sparse` — Manage which paths from the working-copy commit are present in the working copy
 * `split` — Split a revision in two
@@ -1980,6 +1983,26 @@ Show commit description and changes in a revision
 
 
 
+## `jj sign`
+
+Cryptographically sign a revision
+
+**Usage:** `jj sign [OPTIONS] [KEY]`
+
+###### **Arguments:**
+
+* `<KEY>` — What key to use, depends on the configured signing backend
+
+###### **Options:**
+
+* `-r`, `--revision <REVISION>` — What revision to sign
+
+  Default value: `@`
+* `-f`, `--force` — Sign a commit that is not authored by you or was already signed
+* `-D`, `--drop` — Drop the signature, explicitly "un-signing" the commit
+
+
+
 ## `jj simplify-parents`
 
 Simplify parent edges for the specified revision(s).

lib/src/commit_builder.rs

@@ -332,7 +332,7 @@ impl DetachedCommitBuilder {
     }
 
     pub fn set_sign_key(&mut self, sign_key: Option<String>) -> &mut Self {
-        self.sign_settings.key = sign_key;
+        self.sign_settings.key = sign_key.or(self.sign_settings.key.clone());
         self
     }