git: add --all-remotes to git fetch

CHANGELOG.md

@@ -9,6 +9,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * `jj diff --stat` has been implemented. It shows a histogram of the changes,
   same as `git diff --stat`. Fixes [#2066](https://github.com/martinvonz/jj/issues/2066)
 
+* `jj git fetch --all-remotes` has been implemented. It fetches all remotes
+  instead of just the default remote
+
 ### Breaking changes
 
 * The minimum supported Rust version (MSRV) is now 1.71.0.

cli/src/commands/git.rs

@@ -102,6 +102,9 @@ pub struct GitFetchArgs {
     /// repeated)
     #[arg(long = "remote", value_name = "remote")]
     remotes: Vec<String>,
+    /// Fetch from all remotes
+    #[arg(long, conflicts_with = "remotes")]
+    all_remotes: bool,
 }
 
 /// Create a new repo backed by a clone of a Git repo
@@ -314,7 +317,9 @@ fn cmd_git_fetch(
 ) -> Result<(), CommandError> {
     let mut workspace_command = command.workspace_helper(ui)?;
     let git_repo = get_git_repo(workspace_command.repo().store())?;
-    let remotes = if args.remotes.is_empty() {
+    let remotes = if args.all_remotes {
+        get_all_remotes(&git_repo)?
+    } else if args.remotes.is_empty() {
         get_default_fetch_remotes(ui, command.settings(), &git_repo)?
     } else {
         args.remotes.clone()
@@ -379,6 +384,14 @@ fn get_default_fetch_remotes(
     }
 }
 
+fn get_all_remotes(git_repo: &git2::Repository) -> Result<Vec<String>, CommandError> {
+    let git_remotes = git_repo.remotes()?;
+    Ok(git_remotes
+        .iter()
+        .filter_map(|x| x.map(ToOwned::to_owned))
+        .collect())
+}
+
 fn absolute_git_source(cwd: &Path, source: &str) -> String {
     // Git appears to turn URL-like source to absolute path if local git directory
     // exits, and fails because '$PWD/https' is unsupported protocol. Since it would

cli/tests/test_git_fetch.rs

@@ -98,6 +98,22 @@ fn test_git_fetch_single_remote() {
     "###);
 }
 
+#[test]
+fn test_git_fetch_single_remote_all_remotes_flag() {
+    let test_env = TestEnvironment::default();
+    test_env.jj_cmd_success(test_env.env_root(), &["init", "repo", "--git"]);
+    let repo_path = test_env.env_root().join("repo");
+    add_git_remote(&test_env, &repo_path, "rem1");
+
+    test_env
+        .jj_cmd(&repo_path, &["git", "fetch", "--all-remotes"])
+        .assert()
+        .success();
+    insta::assert_snapshot!(get_branch_output(&test_env, &repo_path), @r###"
+    rem1: qxosxrvv 6a211027 message
+    "###);
+}
+
 #[test]
 fn test_git_fetch_single_remote_from_arg() {
     let test_env = TestEnvironment::default();
@@ -143,6 +159,21 @@ fn test_git_fetch_multiple_remotes() {
     "###);
 }
 
+#[test]
+fn test_git_fetch_all_remotes() {
+    let test_env = TestEnvironment::default();
+    test_env.jj_cmd_success(test_env.env_root(), &["init", "repo", "--git"]);
+    let repo_path = test_env.env_root().join("repo");
+    add_git_remote(&test_env, &repo_path, "rem1");
+    add_git_remote(&test_env, &repo_path, "rem2");
+
+    test_env.jj_cmd_success(&repo_path, &["git", "fetch", "--all-remotes"]);
+    insta::assert_snapshot!(get_branch_output(&test_env, &repo_path), @r###"
+    rem1: qxosxrvv 6a211027 message
+    rem2: yszkquru 2497a8a0 message
+    "###);
+}
+
 #[test]
 fn test_git_fetch_multiple_remotes_from_config() {
     let test_env = TestEnvironment::default();