view: add has_branch(name), replace some of get_branch(name) callers

get_branch(name) will be removed soon.

cli/src/commands/branch.rs

@@ -295,10 +295,8 @@ fn cmd_branch_forget(
 ) -> Result<(), CommandError> {
     let mut workspace_command = command.workspace_helper(ui)?;
     let view = workspace_command.repo().view();
-    for branch_name in args.names.iter() {
-        if view.get_branch(branch_name).is_none() {
-            return Err(user_error(format!("No such branch: {branch_name}")));
-        }
+    if let Some(branch_name) = args.names.iter().find(|name| !view.has_branch(name)) {
+        return Err(user_error(format!("No such branch: {branch_name}")));
     }
     let globbed_names = find_globs(view, &args.glob, true)?;
     let names: BTreeSet<String> = args.names.iter().cloned().chain(globbed_names).collect();

lib/src/repo.rs

@@ -979,6 +979,12 @@ impl MutableRepo {
         self.view.mark_dirty();
     }
 
+    /// Returns true if any local or remote branch of the given `name` exists.
+    #[must_use]
+    pub fn has_branch(&self, name: &str) -> bool {
+        self.view.with_ref(|v| v.has_branch(name))
+    }
+
     pub fn get_branch(&self, name: &str) -> Option<BranchTarget> {
         self.view.with_ref(|v| v.get_branch(name).cloned())
     }

lib/src/view.rs

@@ -148,6 +148,12 @@ impl View {
         }
     }
 
+    /// Returns true if any local or remote branch of the given `name` exists.
+    #[must_use]
+    pub fn has_branch(&self, name: &str) -> bool {
+        self.data.branches.contains_key(name)
+    }
+
     pub fn get_branch(&self, name: &str) -> Option<&BranchTarget> {
         self.data.branches.get(name)
     }

lib/tests/test_git.rs

@@ -476,7 +476,7 @@ fn test_import_refs_reimport_with_deleted_remote_ref() {
             },
         }),
     );
-    view.get_branch("main").unwrap(); // branch #3 of 3
+    assert!(view.has_branch("main")); // branch #3 of 3
 
     // Simulate fetching from a remote where feature-remote-only and
     // feature-remote-and-local branches were deleted. This leads to the
@@ -492,8 +492,8 @@ fn test_import_refs_reimport_with_deleted_remote_ref() {
     let view = repo.view();
     // The local branches were indeed deleted
     assert_eq!(view.branches().len(), 2);
-    assert!(view.get_branch("main").is_some());
-    assert!(view.get_branch("feature-remote-only").is_none());
+    assert!(view.has_branch("main"));
+    assert!(!view.has_branch("feature-remote-only"));
     assert_eq!(
         view.get_branch("feature-remote-and-local"),
         Some(&BranchTarget {
@@ -574,7 +574,7 @@ fn test_import_refs_reimport_with_moved_remote_ref() {
             },
         }),
     );
-    view.get_branch("main").unwrap(); // branch #3 of 3
+    assert!(view.has_branch("main")); // branch #3 of 3
 
     // Simulate fetching from a remote where feature-remote-only and
     // feature-remote-and-local branches were moved. This leads to the
@@ -619,7 +619,7 @@ fn test_import_refs_reimport_with_moved_remote_ref() {
             },
         }),
     );
-    view.get_branch("main").unwrap(); // branch #3 of 3
+    assert!(view.has_branch("main")); // branch #3 of 3
     let expected_heads = hashset! {
             jj_id(&commit_main),
             jj_id(&new_commit_remote_and_local),
@@ -844,9 +844,9 @@ fn test_import_some_refs() {
         view.get_branch("feature4"),
         Some(expected_feature4_branch).as_ref()
     );
-    assert_eq!(view.get_branch("main"), None,);
+    assert!(!view.has_branch("main"));
     assert!(!view.heads().contains(&jj_id(&commit_main)));
-    assert_eq!(view.get_branch("ignored"), None,);
+    assert!(!view.has_branch("ignored"));
     assert!(!view.heads().contains(&jj_id(&commit_ign)));
 
     // Delete branch feature1, feature3 and feature4 in git repository and import
@@ -1900,7 +1900,7 @@ fn test_fetch_prune_deleted_ref() {
     )
     .unwrap();
     // Test the setup
-    assert!(tx.mut_repo().get_branch("main").is_some());
+    assert!(tx.mut_repo().has_branch("main"));
 
     test_data
         .origin_repo
@@ -1919,7 +1919,7 @@ fn test_fetch_prune_deleted_ref() {
     )
     .unwrap();
     assert_eq!(stats.import_stats.abandoned_commits, vec![jj_id(&commit)]);
-    assert!(tx.mut_repo().get_branch("main").is_none());
+    assert!(!tx.mut_repo().has_branch("main"));
 }
 
 #[test]