Be more specific when warning the user about missing identity configs

Check if only the email or the name are missing in the config and specifically name the missing one, instead of always defaulting to potentially both missing.

cli/src/cli_util.rs

@@ -1771,13 +1771,31 @@ See https://martinvonz.github.io/jj/latest/working-copy/#stale-working-copy \
         self.report_repo_changes(ui, &old_repo)?;
 
         let settings = self.settings();
-        if settings.user_name().is_empty() || settings.user_email().is_empty() {
+        let missing_user_name = settings.user_name().is_empty();
+        let missing_user_mail = settings.user_email().is_empty();
+        if missing_user_name || missing_user_mail {
+            let mut writer = ui.warning_default();
+            let not_configured_msg = match (missing_user_name, missing_user_mail) {
+                (true, true) => "Name and email not configured.",
+                (true, false) => "Name not configured.",
+                (false, true) => "Email not configured.",
+                _ => unreachable!(),
+            };
+            write!(writer, "{not_configured_msg} ")?;
             writeln!(
-                ui.warning_default(),
+                writer,
-                r#"Name and email not configured. Until configured, your commits will be created with the empty identity, and can't be pushed to remotes. To configure, run:
+                "Until configured, your commits will be created with the empty identity, and \
-  jj config set --user user.name "Some One"
+                 can't be pushed to remotes. To configure, run:",
-  jj config set --user user.email "someone@example.com""#
             )?;
+            if missing_user_name {
+                writeln!(writer, r#"  jj config set --user user.name "Some One""#)?;
+            }
+            if missing_user_mail {
+                writeln!(
+                    writer,
+                    r#"  jj config set --user user.email "someone@example.com""#
+                )?;
+            }
         }
         Ok(())
     }

cli/tests/test_global_opts.rs

@@ -568,9 +568,8 @@ fn test_no_user_configured() {
     insta::assert_snapshot!(get_stderr_string(&assert), @r###"
     Working copy now at: qpvuntsm 7a7d6016 (empty) without name
     Parent commit      : zzzzzzzz 00000000 (empty) (no description set)
-    Warning: Name and email not configured. Until configured, your commits will be created with the empty identity, and can't be pushed to remotes. To configure, run:
+    Warning: Name not configured. Until configured, your commits will be created with the empty identity, and can't be pushed to remotes. To configure, run:
       jj config set --user user.name "Some One"
-      jj config set --user user.email "someone@example.com"
     "###);
     let assert = test_env
         .jj_cmd(&repo_path, &["describe", "-m", "without email"])
@@ -580,6 +579,18 @@ fn test_no_user_configured() {
     insta::assert_snapshot!(get_stderr_string(&assert), @r###"
     Working copy now at: qpvuntsm 906f8b89 (empty) without email
     Parent commit      : zzzzzzzz 00000000 (empty) (no description set)
+    Warning: Email not configured. Until configured, your commits will be created with the empty identity, and can't be pushed to remotes. To configure, run:
+      jj config set --user user.email "someone@example.com"
+    "###);
+    let assert = test_env
+        .jj_cmd(&repo_path, &["describe", "-m", "without name and email"])
+        .env_remove("JJ_USER")
+        .env_remove("JJ_EMAIL")
+        .assert()
+        .success();
+    insta::assert_snapshot!(get_stderr_string(&assert), @r###"
+    Working copy now at: qpvuntsm 57d3a489 (empty) without name and email
+    Parent commit      : zzzzzzzz 00000000 (empty) (no description set)
     Warning: Name and email not configured. Until configured, your commits will be created with the empty identity, and can't be pushed to remotes. To configure, run:
       jj config set --user user.name "Some One"
       jj config set --user user.email "someone@example.com"