fix(lsp): handle mbc properly when formatting (#9273)

4 files changed, 157 insertions, 7 deletions

diff --git a/cli/lsp/language_server.rs b/cli/lsp/language_server.rs
index 55ae92c00..b322438fa 100644
--- a/cli/lsp/language_server.rs
+++ b/cli/lsp/language_server.rs
@@ -669,7 +669,7 @@ impl Inner {
         )
       })?
       .unwrap();
-
+    let line_index = self.documents.line_index(&specifier);
     let file_path =
       if let Ok(file_path) = params.text_document.uri.to_file_path() {
         file_path
@@ -685,7 +685,9 @@ impl Inner {
       // TODO(@kitsonk) this could be handled better in `cli/tools/fmt.rs` in the
       // future.
       match dprint::format_text(&file_path, &file_text, &config) {
-        Ok(new_text) => Some(text::get_edits(&file_text, &new_text)),
+        Ok(new_text) => {
+          Some(text::get_edits(&file_text, &new_text, line_index))
+        }
         Err(err) => {
           warn!("Format error: {}", err);
           None
@@ -702,6 +704,7 @@ impl Inner {
         Ok(Some(text_edits))
       }
     } else {
+      self.client.show_message(MessageType::Warning, format!("Unable to format \"{}\". Likely due to unrecoverable syntax errors in the file.", specifier)).await;
       Ok(None)
     }
   }
@@ -1525,6 +1528,81 @@ mod tests {
   }
 
   #[tokio::test]
+  async fn test_format_mbc() {
+    let mut harness = LspTestHarness::new(vec![
+      ("initialize_request.json", LspResponse::RequestAny),
+      ("initialized_notification.json", LspResponse::None),
+      ("did_open_notification_mbc_fmt.json", LspResponse::None),
+      (
+        "formatting_request_mbc_fmt.json",
+        LspResponse::Request(
+          2,
+          json!([
+            {
+              "range": {
+                "start": {
+                  "line": 0,
+                  "character": 12
+                },
+                "end": {
+                  "line": 0,
+                  "character": 13,
+                }
+              },
+              "newText": "\""
+            },
+            {
+              "range": {
+                "start": {
+                  "line": 0,
+                  "character": 21
+                },
+                "end": {
+                  "line": 0,
+                  "character": 22
+                }
+              },
+              "newText": "\";"
+            },
+            {
+              "range": {
+                "start": {
+                  "line": 1,
+                  "character": 12,
+                },
+                "end": {
+                  "line": 1,
+                  "character": 13,
+                }
+              },
+              "newText": "\""
+            },
+            {
+              "range": {
+                "start": {
+                  "line": 1,
+                  "character": 23,
+                },
+                "end": {
+                  "line": 1,
+                  "character": 25,
+                }
+              },
+              "newText": "\");"
+            }
+          ]),
+        ),
+      ),
+      (
+        "shutdown_request.json",
+        LspResponse::Request(3, json!(null)),
+      ),
+      ("exit_notification.json", LspResponse::None),
+    ]);
+    harness.run().await;
+  }
+
+  #[tokio::test]
   async fn test_large_doc_change() {
     let mut harness = LspTestHarness::new(vec![
       ("initialize_request.json", LspResponse::RequestAny),
diff --git a/cli/lsp/text.rs b/cli/lsp/text.rs
index 1d350c12f..f444d639e 100644
--- a/cli/lsp/text.rs
+++ b/cli/lsp/text.rs
@@ -181,8 +181,8 @@ impl LineIndex {
 
   /// Returns a u16 position based on a u8 offset.
   pub fn position_utf16(&self, offset: TextSize) -> lsp_types::Position {
-    let line = partition_point(&self.utf8_offsets, |&it| it <= offset) - 1;
-    let line_start_offset = self.utf8_offsets[line];
+    let line = partition_point(&self.utf16_offsets, |&it| it <= offset) - 1;
+    let line_start_offset = self.utf16_offsets[line];
     let col = offset - line_start_offset;
 
     lsp_types::Position {
@@ -208,13 +208,21 @@ impl LineIndex {
 
 /// Compare two strings and return a vector of text edit records which are
 /// supported by the Language Server Protocol.
-pub fn get_edits(a: &str, b: &str) -> Vec<TextEdit> {
+pub fn get_edits(
+  a: &str,
+  b: &str,
+  maybe_line_index: Option<LineIndex>,
+) -> Vec<TextEdit> {
   if a == b {
     return vec![];
   }
   let chunks = diff(a, b);
   let mut text_edits = Vec::<TextEdit>::new();
-  let line_index = LineIndex::new(a);
+  let line_index = if let Some(line_index) = maybe_line_index {
+    line_index
+  } else {
+    LineIndex::new(a)
+  };
   let mut iter = chunks.iter().peekable();
   let mut a_pos = TextSize::from(0);
   loop {
@@ -565,7 +573,7 @@ const C: char = \"メ メ\";
   fn test_get_edits() {
     let a = "abcdefg";
     let b = "a\nb\nchije\nfg\n";
-    let actual = get_edits(a, b);
+    let actual = get_edits(a, b, None);
     assert_eq!(
       actual,
       vec![
@@ -600,6 +608,44 @@ const C: char = \"メ メ\";
   }
 
   #[test]
+  fn test_get_edits_mbc() {
+    let a = "const bar = \"👍🇺🇸😃\";\nconsole.log('hello deno')\n";
+    let b = "const bar = \"👍🇺🇸😃\";\nconsole.log(\"hello deno\");\n";
+    let actual = get_edits(a, b, None);
+    assert_eq!(
+      actual,
+      vec![
+        TextEdit {
+          range: lsp_types::Range {
+            start: lsp_types::Position {
+              line: 1,
+              character: 12
+            },
+            end: lsp_types::Position {
+              line: 1,
+              character: 13
+            }
+          },
+          new_text: "\"".to_string()
+        },
+        TextEdit {
+          range: lsp_types::Range {
+            start: lsp_types::Position {
+              line: 1,
+              character: 23
+            },
+            end: lsp_types::Position {
+              line: 1,
+              character: 25
+            }
+          },
+          new_text: "\");".to_string()
+        },
+      ]
+    )
+  }
+
+  #[test]
   fn test_get_range_change() {
     let a = "abcdefg";
     let b = "abcdefg";
diff --git a/cli/tests/lsp/did_open_notification_mbc_fmt.json b/cli/tests/lsp/did_open_notification_mbc_fmt.json
new file mode 100644
index 000000000..528dad25d
--- /dev/null
+++ b/cli/tests/lsp/did_open_notification_mbc_fmt.json
@@ -0,0 +1,12 @@
+{
+  "jsonrpc": "2.0",
+  "method": "textDocument/didOpen",
+  "params": {
+    "textDocument": {
+      "uri": "file:///a/file.ts",
+      "languageId": "typescript",
+      "version": 1,
+      "text": "const bar = '👍🇺🇸😃'\nconsole.log('hello deno')\n"
+    }
+  }
+}
diff --git a/cli/tests/lsp/formatting_request_mbc_fmt.json b/cli/tests/lsp/formatting_request_mbc_fmt.json
new file mode 100644
index 000000000..f20cc18e6
--- /dev/null
+++ b/cli/tests/lsp/formatting_request_mbc_fmt.json
@@ -0,0 +1,14 @@
+{
+  "jsonrpc": "2.0",
+  "id": 2,
+  "method": "textDocument/formatting",
+  "params": {
+    "textDocument": {
+      "uri": "file:///a/file.ts"
+    },
+    "options": {
+      "tabSize": 2,
+      "insertSpaces": true
+    }
+  }
+}