templater: move empty signature placeholder to user template

This patch also extracts format_detailed_signature() function to deduplicate
the "show" template bits.

The added placeholder templates aren't labeled as "empty". If needed, I think
the whole template can be labeled as "empty" (or "empty_commit") just like
"working_copy".

Closes #2112

CHANGELOG.md

@@ -38,7 +38,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   can be customized with the `snapshot.max-new-file-size` config option.
 
 * Author and committer signatures now use empty strings to represent unset
-  names and email addresses.
+  names and email addresses. The `author`/`committer` template keywords and
+  methods also return empty strings.
   Older binaries may not warn user when attempting to `git push` commits
   with such signatures.
 

cli/src/config/templates.toml

@@ -40,7 +40,7 @@ if(root,
           separate(" ",
             format_short_change_id(change_id) ++ if(divergent, "??"),
             if(hidden, "hidden"))),
-        author.username(),
+        if(author.email(), author.username(), email_placeholder),
         format_timestamp(committer.timestamp()),
         branches,
         tags,
@@ -89,8 +89,8 @@ builtin_log_comfortable = 'builtin_log_compact ++ "\n"'
 concat(
   "Commit ID: " ++ commit_id ++ "\n",
   "Change ID: " ++ change_id ++ "\n",
-  "Author: " ++ author ++ " (" ++ format_timestamp(author.timestamp()) ++ ")\n",
-  "Committer: " ++ committer ++ " (" ++ format_timestamp(committer.timestamp()) ++ ")\n",
+  "Author: " ++ format_detailed_signature(author) ++ "\n",
+  "Committer: " ++ format_detailed_signature(committer)  ++ "\n",
   "\n",
   indent("    ", if(description, description, description_placeholder ++ "\n")),
   "\n",
@@ -123,13 +123,20 @@ separate(" ",
 
 description_placeholder = '''
   label(if(empty, "empty ") ++ "description placeholder", "(no description set)")'''
+email_placeholder = 'label("email placeholder", "(no email available)")'
+name_placeholder = 'label("name placeholder", "(no name available)")'
 commit_summary_separator = 'label("separator", " | ")'
 
 # Hook points for users to customize the default templates:
 'format_short_id(id)' = 'id.shortest(8)'
 'format_short_change_id(id)' = 'format_short_id(id)'
 'format_short_commit_id(id)' = 'format_short_id(id)'
-'format_short_signature(signature)' = 'signature.email()'
+'format_short_signature(signature)' = '''
+  if(signature.email(), signature.email(), email_placeholder)'''
+'format_detailed_signature(signature)' = '''
+  if(signature.name(), signature.name(), name_placeholder)
+  ++ " <" ++ if(signature.email(), signature.email(), email_placeholder) ++ ">"
+  ++ " (" ++ format_timestamp(signature.timestamp()) ++ ")"'''
 'format_time_range(time_range)' = '''
   time_range.start().ago() ++ label("time", ", lasted ") ++ time_range.duration()'''
 'format_timestamp(timestamp)' = 'timestamp'

cli/src/template_builder.rs

@@ -456,32 +456,20 @@ fn build_signature_method<'a, L: TemplateLanguage<'a>>(
         "name" => {
             template_parser::expect_no_arguments(function)?;
             language.wrap_string(TemplateFunction::new(self_property, |signature| {
-                if !signature.name.is_empty() {
-                    signature.name
-                } else {
-                    "(no name available)".to_string()
-                }
+                signature.name
             }))
         }
         "email" => {
             template_parser::expect_no_arguments(function)?;
             language.wrap_string(TemplateFunction::new(self_property, |signature| {
-                if !signature.email.is_empty() {
-                    signature.email
-                } else {
-                    "(no email available)".to_string()
-                }
+                signature.email
             }))
         }
         "username" => {
             template_parser::expect_no_arguments(function)?;
             language.wrap_string(TemplateFunction::new(self_property, |signature| {
-                if !signature.email.is_empty() {
-                    let (username, _) = text_util::split_email(&signature.email);
-                    username.to_owned()
-                } else {
-                    "(no username available)".to_string()
-                }
+                let (username, _) = text_util::split_email(&signature.email);
+                username.to_owned()
             }))
         }
         "timestamp" => {

cli/src/templater.rs

@@ -57,18 +57,15 @@ impl<C, T: Template<C> + ?Sized> Template<C> for Box<T> {
 
 impl Template<()> for Signature {
     fn format(&self, _: &(), formatter: &mut dyn Formatter) -> io::Result<()> {
-        if !self.name.is_empty() {
-            write!(formatter.labeled("name"), "{}", self.name)?;
-        } else {
-            write!(formatter.labeled("name"), "(no name available)")?;
+        write!(formatter.labeled("name"), "{}", self.name)?;
+        if !self.name.is_empty() && !self.email.is_empty() {
+            write!(formatter, " ")?;
         }
-        write!(formatter, " <")?;
         if !self.email.is_empty() {
+            write!(formatter, "<")?;
             write!(formatter.labeled("email"), "{}", self.email)?;
-        } else {
-            write!(formatter.labeled("email"), "(no email available)")?;
+            write!(formatter, ">")?;
         }
-        write!(formatter, ">")?;
         Ok(())
     }
 }

cli/tests/test_commit_template.rs

@@ -182,7 +182,7 @@ fn test_log_builtin_templates() {
     );
 
     insta::assert_snapshot!(render(r#"builtin_log_oneline"#), @r###"
-    @  rlvkpnrz (no username available) 2001-02-03 04:05:08.000 +07:00 dc315397 (empty) (no description set)
+    @  rlvkpnrz (no email available) 2001-02-03 04:05:08.000 +07:00 dc315397 (empty) (no description set)
     ◉  qpvuntsm test.user 2001-02-03 04:05:07.000 +07:00 230dd059 (empty) (no description set)
     ◉  zzzzzzzz root 00000000
     "###);

cli/tests/test_templater.rs

@@ -463,17 +463,17 @@ fn test_templater_signature() {
 
     test_env.jj_cmd_ok(&repo_path, &["--config-toml=user.name=''", "new"]);
 
-    insta::assert_snapshot!(render(r#"author"#), @"(no name available) <test.user@example.com>");
-    insta::assert_snapshot!(render(r#"author.name()"#), @"(no name available)");
+    insta::assert_snapshot!(render(r#"author"#), @"<test.user@example.com>");
+    insta::assert_snapshot!(render(r#"author.name()"#), @"");
     insta::assert_snapshot!(render(r#"author.email()"#), @"test.user@example.com");
     insta::assert_snapshot!(render(r#"author.username()"#), @"test.user");
 
     test_env.jj_cmd_ok(&repo_path, &["--config-toml=user.email=''", "new"]);
 
-    insta::assert_snapshot!(render(r#"author"#), @"Test User <(no email available)>");
+    insta::assert_snapshot!(render(r#"author"#), @"Test User");
     insta::assert_snapshot!(render(r#"author.name()"#), @"Test User");
-    insta::assert_snapshot!(render(r#"author.email()"#), @"(no email available)");
-    insta::assert_snapshot!(render(r#"author.username()"#), @"(no username available)");
+    insta::assert_snapshot!(render(r#"author.email()"#), @"");
+    insta::assert_snapshot!(render(r#"author.username()"#), @"");
 
     test_env.jj_cmd_ok(
         &repo_path,
@@ -484,10 +484,10 @@ fn test_templater_signature() {
         ],
     );
 
-    insta::assert_snapshot!(render(r#"author"#), @"(no name available) <(no email available)>");
-    insta::assert_snapshot!(render(r#"author.name()"#), @"(no name available)");
-    insta::assert_snapshot!(render(r#"author.email()"#), @"(no email available)");
-    insta::assert_snapshot!(render(r#"author.username()"#), @"(no username available)");
+    insta::assert_snapshot!(render(r#"author"#), @"");
+    insta::assert_snapshot!(render(r#"author.name()"#), @"");
+    insta::assert_snapshot!(render(r#"author.email()"#), @"");
+    insta::assert_snapshot!(render(r#"author.username()"#), @"");
 }
 
 #[test]