fix: report correct amount of files opened and improved error message when Helix can't parse directory as file (#12199)

* feat: improve information on the amount of files loaded

* refactor: naming consitency Doc and not Buf

* fix: correct name of method

* chore: appease clippy

* feat: more human error information when Helix cannot start

* refatcor: use if guard on match arm

helix-term/src/application.rs

@@ -175,7 +175,7 @@ pub fn new(args: Args, config: Config, lang_loader: syntax::Loader) -> Result<Se
                     nr_of_files += 1;
                     if file.is_dir() {
                         return Err(anyhow::anyhow!(
-                            "expected a path to file, found a directory. (to open a directory pass it as first argument)"
+                            "expected a path to file, but found a directory: {file:?}. (to open a directory pass it as first argument)"
                         ));
                     } else {
                         // If the user passes in either `--vsplit` or
@@ -189,6 +189,7 @@ pub fn new(args: Args, config: Config, lang_loader: syntax::Loader) -> Result<Se
                             Some(Layout::Horizontal) => Action::HorizontalSplit,
                             None => Action::Load,
                         };
+                        let old_id = editor.document_id_by_path(&file);
                         let doc_id = match editor.open(&file, action) {
                             // Ignore irregular files during application init.
                             Err(DocumentOpenError::IrregularFile) => {
@@ -196,6 +197,11 @@ pub fn new(args: Args, config: Config, lang_loader: syntax::Loader) -> Result<Se
                                 continue;
                             }
                             Err(err) => return Err(anyhow::anyhow!(err)),
+                            // We can't open more than 1 buffer for 1 file, in this case we already have opened this file previously
+                            Ok(doc_id) if old_id == Some(doc_id) => {
+                                nr_of_files -= 1;
+                                doc_id
+                            }
                             Ok(doc_id) => doc_id,
                         };
                         // with Action::Load all documents have the same view

helix-term/src/main.rs

@@ -154,8 +154,7 @@ async fn main_impl() -> Result<i32> {
     });
 
     // TODO: use the thread local executor to spawn the application task separately from the work pool
-    let mut app =
-        Application::new(args, config, lang_loader).context("unable to create new application")?;
+    let mut app = Application::new(args, config, lang_loader).context("unable to start Helix")?;
 
     let exit_code = app.run(&mut EventStream::new()).await?;
 

helix-view/src/editor.rs

@@ -1718,10 +1718,14 @@ pub fn new_file_from_stdin(&mut self, action: Action) -> Result<DocumentId, Erro
         Ok(doc_id)
     }
 
+    pub fn document_id_by_path(&self, path: &Path) -> Option<DocumentId> {
+        self.document_by_path(path).map(|doc| doc.id)
+    }
+
     // ??? possible use for integration tests
     pub fn open(&mut self, path: &Path, action: Action) -> Result<DocumentId, DocumentOpenError> {
         let path = helix_stdx::path::canonicalize(path);
-        let id = self.document_by_path(&path).map(|doc| doc.id);
+        let id = self.document_id_by_path(&path);
 
         let id = if let Some(id) = id {
             id