Centralize Diagnostic formatting, expose from Rust

Cargo.toml

@@ -33,6 +33,7 @@ rayon = "1.10.0"
 parking_lot = "0.12.3"
 itertools = "0.14.0"
 toml_edit = "0.22.22"
+console = "0.15.10"
 
 [features]
 extension-module = ["pyo3/extension-module"]

python/tach/cli.py

@@ -27,6 +27,7 @@
     check_computation_cache,
     create_computation_cache_key,
     detect_unused_dependencies,
+    format_diagnostics,
     run_server,
     serialize_diagnostics_json,
     update_computation_cache,
@@ -644,7 +645,11 @@ def tach_check(
                 json.dump({"error": str(e)}, sys.stdout)
             sys.exit(1 if has_errors else 0)
 
-        print_diagnostics(diagnostics, project_root=project_root)
+        if diagnostics:
+            print(
+                format_diagnostics(project_root=project_root, diagnostics=diagnostics),
+                file=sys.stderr,
+            )
         exit_code = 1 if has_errors else 0
 
         # If we're checking in exact mode, we want to verify that there are no unused dependencies
@@ -696,14 +701,14 @@ def tach_check_external(
             exclude_paths=exclude_paths,
         )
 
-        warnings = list(filter(lambda d: d.is_warning(), diagnostics))
-        errors = list(filter(lambda d: d.is_error(), diagnostics))
-        for diagnostic in warnings:
-            print(diagnostic.to_string())
-        for diagnostic in errors:
-            print(diagnostic.to_string())
+        if diagnostics:
+            print(
+                format_diagnostics(project_root=project_root, diagnostics=diagnostics),
+                file=sys.stderr,
+            )
 
-        if errors:
+        has_errors = any(diagnostic.is_error() for diagnostic in diagnostics)
+        if has_errors:
             sys.exit(1)
         else:
             print(

python/tach/extension.pyi

@@ -61,6 +61,10 @@ def check_external_dependencies(
     module_mappings: dict[str, list[str]],
     stdlib_modules: list[str],
 ) -> list[Diagnostic]: ...
+def format_diagnostics(
+    project_root: Path,
+    diagnostics: list[Diagnostic],
+) -> str: ...
 def detect_unused_dependencies(
     project_root: Path,
     project_config: ProjectConfig,

python/tests/test_check.py

@@ -25,7 +25,7 @@ def test_valid_example_dir(example_dir, capfd):
     assert exc_info.value.code == 0
     captured = capfd.readouterr()
     assert SUCCESS in captured.out
-    assert WARNING in captured.err
+    assert WARNING in captured.err or "WARN" in captured.err
 
 
 def test_valid_example_dir_monorepo(example_dir):

python/tests/test_cli.py

@@ -6,7 +6,7 @@
 import pytest
 
 from tach import cli
-from tach.extension import Diagnostic, ProjectConfig
+from tach.extension import ProjectConfig
 
 
 @pytest.fixture
@@ -41,28 +41,6 @@ def test_execute_with_config(capfd, mock_check, mock_project_config):
     assert "All modules validated!" in captured.out
 
 
-def test_execute_with_error(capfd, mock_check, mock_project_config):
-    # Mock an error returned from check
-    location = Path("valid_dir/file.py")
-    message = "Import valid_dir in valid_dir/file.py is blocked by boundary"
-    mock_diagnostic = Mock(spec=Diagnostic)
-    mock_diagnostic.is_error.return_value = True
-    mock_diagnostic.to_string.return_value = message
-    mock_diagnostic.pyfile_path.return_value = location
-    mock_diagnostic.pyline_number.return_value = 0
-    mock_check.return_value = [mock_diagnostic]
-    with pytest.raises(SystemExit) as sys_exit:
-        cli.tach_check(
-            project_root=Path(),
-            project_config=mock_project_config,
-            exclude_paths=mock_project_config.exclude,
-        )
-    captured = capfd.readouterr()
-    assert sys_exit.value.code == 1
-    assert str(location) in captured.err
-    assert message in captured.err
-
-
 def test_invalid_command(capfd):
     with pytest.raises(SystemExit) as sys_exit:
         # Test with an invalid command

src/cli.rs

@@ -1,6 +1,8 @@
 use std::env;
 use std::path::Path;
 
+use console::Term;
+
 #[derive(Debug, PartialEq, Eq)]
 enum TerminalEnvironment {
     Unknown,
@@ -41,3 +43,53 @@ pub fn create_clickable_link(file_path: &Path, abs_path: &Path, line: &usize) ->
     let display_with_line = format!("{}[L{}]", file_path_str, line);
     format!("\x1b]8;;{}\x1b\\{}\x1b]8;;\x1b\\", link, display_with_line)
 }
+
+pub fn supports_emoji() -> bool {
+    let term = Term::stdout();
+    term.is_term() && term.features().wants_emoji()
+}
+
+pub fn supports_colors() -> bool {
+    let term = Term::stdout();
+    term.is_term() && term.features().colors_supported()
+}
+
+pub struct EmojiIcons;
+
+impl EmojiIcons {
+    pub const SUCCESS: &str = "✅";
+    pub const WARNING: &str = "⚠️ ";
+    pub const FAIL: &str = "❌";
+}
+
+pub struct SimpleIcons;
+
+impl SimpleIcons {
+    pub const SUCCESS: &str = "[OK]";
+    pub const WARNING: &str = "[WARN]";
+    pub const FAIL: &str = "[FAIL]";
+}
+
+pub fn success() -> &'static str {
+    if supports_emoji() {
+        EmojiIcons::SUCCESS
+    } else {
+        SimpleIcons::SUCCESS
+    }
+}
+
+pub fn warning() -> &'static str {
+    if supports_emoji() {
+        EmojiIcons::WARNING
+    } else {
+        SimpleIcons::WARNING
+    }
+}
+
+pub fn fail() -> &'static str {
+    if supports_emoji() {
+        EmojiIcons::FAIL
+    } else {
+        SimpleIcons::FAIL
+    }
+}