Improvements to formatter cli interface (#3553)

Author: marsninja

docs/docs/communityhub/release_notes/jaclang.md

@@ -2,9 +2,11 @@
 
 This document provides a summary of new features, improvements, and bug fixes in each version of **Jaclang**. For details on changes that might require updates to your existing code, please refer to the [Breaking Changes](../breaking_changes.md) page.
 
-## jaclang 0.9.3 (Unreleased)
+## jaclang 0.9.4 (Unreleased)
 
-## jaclang 0.9.2(Latest Release)
+- **Format Command Enhancements**: The `jac format` command now tracks and reports which files were actually changed during formatting. The summary output shows both total files processed and the count of files that were modified (e.g., `Formatted 10/12 '.jac' files (3 changed).`). Additionally, syntax errors encountered during formatting are now printed with full error details.
+
+## jaclang 0.9.3 (Latest Release)
 
 - **Fixed JSX Text Parsing for Keywords**: Fixed a parser issue where keywords like `to`, `as`, `in`, `is`, `for`, `if`, etc. appearing as text content within JSX elements would cause parse errors. The grammar now correctly recognizes these common English words as valid JSX text content.
 - **Support iter for statement**: Iter for statement is supported in order to utilize traditional for loop in javascript.

jac/jaclang/cli/cli.py

@@ -61,40 +61,54 @@ def write_formatted_code(code: str, target_path: str) -> None:
             with open(target_path, "w") as f:
                 f.write(code)
 
-    def format_single_file(file_path: str) -> bool:
-        """Format a single .jac file. Returns True on success."""
+    def format_single_file(file_path: str) -> tuple[bool, bool]:
+        """Format a single .jac file. Returns (success, changed)."""
         path_obj = Path(file_path)
         if not path_obj.exists():
             print(f"Error: File '{file_path}' does not exist.", file=sys.stderr)
-            return False
+            return False, False
         try:
-            formatted_code = JacProgram.jac_file_formatter(str(path_obj))
+            prog = JacProgram.jac_file_formatter(str(path_obj))
+            if prog.errors_had:
+                for error in prog.errors_had:
+                    print(f"{error}", file=sys.stderr)
+                return False, False
+            formatted_code = prog.mod.main.gen.jac
+            original_code = prog.mod.main.source.code
+            changed = formatted_code != original_code
             write_formatted_code(formatted_code, str(path_obj))
-            return True
+            return True, changed
         except Exception as e:
             print(f"Error formatting '{file_path}': {e}", file=sys.stderr)
-            return False
+            return False, False
 
     total_files = 0
     failed_files = 0
+    changed_files = 0
 
     for path in paths:
         path_obj = Path(path)
 
         # Case 1: Single .jac file
         if path.endswith(".jac"):
             total_files += 1
-            if not format_single_file(path):
+            success, changed = format_single_file(path)
+            if not success:
                 failed_files += 1
+            elif changed:
+                changed_files += 1
             continue
 
         # Case 2: Directory with .jac files
         if path_obj.is_dir():
             jac_files = list(path_obj.glob("**/*.jac"))
             for jac_file in jac_files:
                 total_files += 1
-                if not format_single_file(str(jac_file)):
+                success, changed = format_single_file(str(jac_file))
+                if not success:
                     failed_files += 1
+                elif changed:
+                    changed_files += 1
             continue
 
         # Case 3: Invalid path
@@ -104,7 +118,8 @@ def format_single_file(file_path: str) -> bool:
     # Only print summary for directory processing or when there are failures
     if (len(paths) == 1 and Path(paths[0]).is_dir()) or failed_files > 0:
         print(
-            f"Formatted {total_files - failed_files}/{total_files} '.jac' files.",
+            f"Formatted {total_files - failed_files}/{total_files} '.jac' files "
+            f"({changed_files} changed).",
             file=sys.stderr,
         )
 
@@ -658,14 +673,11 @@ def py2jac(filename: str) -> None:
             ),
             prog=JacProgram(),
         ).ir_out.unparse(requires_format=False)
-        formatted_code = JacProgram().jac_str_formatter(
-            source_str=code, file_path=filename
-        )
-        if formatted_code:
-            print(formatted_code)
-        else:
+        prog = JacProgram.jac_str_formatter(source_str=code, file_path=filename)
+        if prog.errors_had:
             print("Error converting Python code to Jac.", file=sys.stderr)
             exit(1)
+        print(prog.mod.main.gen.jac)
     else:
         print("Not a .py file.")
         exit(1)

jac/jaclang/compiler/passes/tool/tests/test_jac_format_pass.py

@@ -19,7 +19,8 @@ def compare_files(
         with open(original_path) as file:
             original_file_content = file.read()
         if formatted_file is None:
-            formatted_content = JacProgram.jac_file_formatter(original_path)
+            prog = JacProgram.jac_file_formatter(original_path)
+            formatted_content = prog.mod.main.gen.jac
         else:
             with open(fixture_path(formatted_file)) as file:
                 formatted_content = file.read()
@@ -132,7 +133,8 @@ def micro_suite_test(filename: str) -> None:
     Includes a specific token check for 'circle_clean_tests.jac'.
     """
     code_gen_pure = JacProgram().compile(filename)
-    code_gen_format = JacProgram.jac_file_formatter(filename)
+    format_prog = JacProgram.jac_file_formatter(filename)
+    code_gen_format = format_prog.mod.main.gen.jac
     code_gen_jac = JacProgram().compile(use_str=code_gen_format, file_path=filename)
     if "circle_clean_tests.jac" in filename:
         tokens = code_gen_format.split()

jac/jaclang/compiler/program.py

@@ -180,28 +180,26 @@ def run_schedule(
             current_pass(ir_in=mod, prog=self, cancel_token=cancel_token)  # type: ignore
 
     @staticmethod
-    def jac_file_formatter(file_path: str) -> str:
-        """Convert a Jac file to an AST."""
+    def jac_file_formatter(file_path: str) -> JacProgram:
+        """Format a Jac file and return the JacProgram."""
         prog = JacProgram()
         source_str = read_file_with_encoding(file_path)
         source = uni.Source(source_str, mod_path=file_path)
         parser_pass = JacParser(root_ir=source, prog=prog)
         current_mod = parser_pass.ir_out
         for pass_cls in format_sched:
             current_mod = pass_cls(ir_in=current_mod, prog=prog).ir_out
-        parser_pass.errors_had = prog.errors_had
-        parser_pass.warnings_had = prog.warnings_had
-        return current_mod.gen.jac if not parser_pass.errors_had else source_str
+        prog.mod = uni.ProgramModule(current_mod)
+        return prog
 
     @staticmethod
-    def jac_str_formatter(source_str: str, file_path: str) -> str:
-        """Convert a Jac file to an AST."""
+    def jac_str_formatter(source_str: str, file_path: str) -> JacProgram:
+        """Format a Jac string and return the JacProgram."""
         prog = JacProgram()
         source = uni.Source(source_str, mod_path=file_path)
         parser_pass = JacParser(root_ir=source, prog=prog)
         current_mod = parser_pass.ir_out
         for pass_cls in format_sched:
             current_mod = pass_cls(ir_in=current_mod, prog=prog).ir_out
-        parser_pass.errors_had = prog.errors_had
-        parser_pass.warnings_had = prog.warnings_had
-        return current_mod.gen.jac if not parser_pass.errors_had else source_str
+        prog.mod = uni.ProgramModule(current_mod)
+        return prog

jac/jaclang/langserve/engine.jac

@@ -399,9 +399,10 @@ class JacLangServer(JacProgram , LanguageServer) {
     def formatted_jac(self: JacLangServer, file_path: str) -> list[lspt.TextEdit] {
         try {
             document = self.workspace.get_text_document(file_path);
-            formatted_text = JacProgram.jac_str_formatter(
+            prog = JacProgram.jac_str_formatter(
                 source_str=document.source, file_path=document.path
             );
+            formatted_text = prog.mod.main.gen.jac if not prog.errors_had else document.source;
         } except Exception as e {
             self.log_error(f"'Error during formatting: '{e}");
             formatted_text = document.source;

jac/jaclang/tests/test_cli.py

@@ -744,3 +744,30 @@ def test_cli_error_exit_codes(fixture_path) -> None:
     stdout, stderr = process.communicate()
     assert process.returncode == 0, "run command should exit with code 0 on success"
     assert "Hello World!" in stdout
+
+
+def test_format_tracks_changed_files() -> None:
+    """Test that format command correctly tracks and reports changed files."""
+    with tempfile.TemporaryDirectory() as tmpdir:
+        # Create a file that needs formatting (bad indentation/spacing)
+        needs_formatting = os.path.join(tmpdir, "needs_format.jac")
+        with open(needs_formatting, "w") as f:
+            f.write('with entry{print("hello");}')
+
+        # Create a file that is already formatted
+        already_formatted = os.path.join(tmpdir, "already_formatted.jac")
+        with open(already_formatted, "w") as f:
+            f.write('with entry {\n    print("hello");\n}\n')
+
+        # Run format on the directory
+        process = subprocess.Popen(
+            ["jac", "format", tmpdir],
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+            text=True,
+        )
+        stdout, stderr = process.communicate()
+
+        assert process.returncode == 0
+        assert "2/2" in stderr
+        assert "(1 changed)" in stderr