import-analyzer-py 0.1.0

A Python import analyzer with cross-file analysis, unused import detection, and autofix

import-analyzer-py

A Python import analyzer with cross-file analysis, unused import detection, circular import warnings, and autofix.

Comparison with Other Tools

Feature	This tool	Ruff	Autoflake	Pyflakes	Pylint	Unimport
Detect unused imports	✅	✅	✅	✅	✅	✅
Autofix	✅	✅	✅	❌	❌	✅
Cross-file analysis	✅	❌	❌	❌	❌	❌
Re-export tracking	✅	❌¹	❌	❌	❌²	❌
Cascade detection	✅	❌	❌	❌	❌	❌
Circular import warnings	✅	❌	❌	❌	❌	❌
Unreachable file warnings	✅	❌	❌	❌	❌	❌
Respects __all__	✅	✅	⚠️³	✅	✅	✅
noqa: F401 support	✅	✅	✅	❌⁴	✅⁵	✅
Full scope analysis (LEGB)	✅	✅	⚠️⁶	⚠️⁶	✅	✅
String annotations	✅	✅	✅	✅	✅	✅
TYPE_CHECKING blocks	✅	✅	✅	⚠️⁷	✅	✅
Type comments (# type:)	❌	✅	✅	✅	✅	✅
Redundant alias (x as x)	❌	✅	❌	❌	❌	❌
Star import suggestions	❌	❌	❌	❌	❌	✅
Redefinition warnings	❌	✅	❌	✅	✅	❌
Speed	Moderate	🚀 Fast	Moderate	Fast	Slow	Moderate

^{¹ Ruff suggests import X as X for __init__.py but doesn't track actual cross-file usage
² Pylint skips __init__.py by default but doesn't track actual re-export consumers
³ Autoflake only uses __all__ to skip star import expansion, not to preserve re-exports
⁴ Pyflakes has no noqa support; Flake8 adds it as a wrapper layer
⁵ Pylint uses # pylint: disable=unused-import
⁶ Autoflake/Pyflakes have basic scope analysis but miss some LEGB edge cases
⁷ Pyflakes treats TYPE_CHECKING as normal conditional code (works but not explicit)}

What makes this tool unique

Cross-file analysis — This is the only tool that follows imports from your entry point and tracks which imports are actually used by other files. This enables:

• Re-export preservation: If utils.py imports List and main.py does from utils import List, the import in utils.py is correctly identified as used
• Cascade detection: When removing an unused import makes another import unused, this tool finds all of them in a single pass
• Circular import detection: Warns about import cycles in your codebase
• Unreachable file detection: Identifies files that become dead code after fixing imports

Features we don't have (yet)

Based on analysis of other tools' source code:

• Type comments: # type: int style annotations (PEP 484) are not parsed
• Redundant alias detection: import X as X as explicit re-export marker (Ruff feature)
• Star import suggestions: Suggesting specific names to replace from x import * (Unimport feature)
• Redefinition warnings: Warning when an import is reassigned before use (Pyflakes feature)

Installation

pip install import-analyzer

Or install from source:

git clone https://github.com/cmyui/import-analyzer-py
cd import-analyzer-py
pip install .

Usage

Cross-file mode (default)

Cross-file mode follows imports from an entry point and tracks re-exports across your codebase. This prevents false positives when imports are used by other files.

# Analyze from entry point (follows imports)
import-analyzer main.py

# Analyze entire directory
import-analyzer src/

# Fix all unused imports (including cascaded ones)
import-analyzer --fix main.py

# Warn about implicit re-exports (imports used by other files but not in __all__)
import-analyzer --warn-implicit-reexports main.py

# Warn about circular imports
import-analyzer --warn-circular main.py

# Warn about files that become unreachable after fixing
import-analyzer --warn-unreachable main.py

# Quiet mode (summary only)
import-analyzer -q main.py

Single-file mode

For simple use cases or when you want to analyze files independently:

# Check files independently (no cross-file tracking)
import-analyzer --single-file myfile.py

# Check multiple files
import-analyzer --single-file src/*.py

Exit codes

Code	Meaning
0	No unused imports found (or --fix was used)
1	Unused imports found

Features

Cross-file analysis

• Re-export tracking: Imports used by other files are preserved
• Cascade detection: Finds all unused imports in a single pass, even when removing one exposes another
• Circular import detection: Warns about import cycles
• Implicit re-export warnings: Identifies re-exports missing from __all__
• Unreachable file detection: Warns about files that become dead code after fixing imports

Single-file analysis

• Detects unused import X and from X import Y statements
• Handles aliased imports (import X as Y, from X import Y as Z)
• Recognizes usage in:
  • Function calls and attribute access
  • Type annotations (including forward references / string annotations)
  • Decorators and base classes
  • Default argument values
  • __all__ exports
• Skips __future__ imports (they have side effects)
• Respects # noqa: F401 comments (matches flake8 behavior)
• Full scope analysis with LEGB rule:
  • Correctly handles function parameters that shadow imports
  • Handles class scope quirks (class body doesn't enclose nested functions)
  • Supports comprehension scopes and walrus operator bindings
  • Respects global and nonlocal declarations

Directory exclusions

The tool automatically skips common non-source directories:

• Virtual environments: .venv, venv, .env, env
• Build artifacts: build, dist, *.egg-info
• Cache directories: __pycache__, .mypy_cache, .pytest_cache, .ruff_cache
• Version control: .git, .hg, .svn
• Other: node_modules, .tox, .nox, .eggs

Autofix

• Safely handles empty blocks by inserting pass
• Partial removal from multi-import statements
• Handles semicolon-separated statements
• Handles backslash line continuations

Examples

Single-file example

Before:

import os
import sys  # unused
from typing import List, Optional  # List unused
from pathlib import Path

def get_home() -> Optional[Path]:
    return Path(os.environ.get("HOME"))

After (--fix):

import os
from typing import Optional
from pathlib import Path

def get_home() -> Optional[Path]:
    return Path(os.environ.get("HOME"))

Cross-file re-export example

# utils.py
from typing import List  # NOT unused - re-exported to main.py

# main.py
from utils import List
x: List[int] = []

Running import-analyzer main.py correctly preserves the List import in utils.py because it's used by main.py.

Cascade detection example

# main.py
from helpers import List  # unused - not used locally

# helpers.py
from utils import List    # becomes unused when main.py's import is removed

# utils.py
from typing import List   # becomes unused when helpers.py's import is removed

Running import-analyzer --fix main.py removes all three imports in a single pass.

noqa comments

The tool respects # noqa comments matching flake8 behavior:

import os  # noqa: F401  - kept (F401 = unused import)
import sys  # noqa       - kept (bare noqa suppresses all)
import re  # noqa: E501  - flagged (wrong code)

For multi-line imports, noqa applies per-line:

from typing import (
    List,  # noqa: F401  - kept
    Dict,  # flagged (no noqa)
)

Known Limitations

• Star imports: from X import * cannot be analyzed statically
• Dynamic imports: importlib.import_module() calls are not tracked
• Namespace packages: PEP 420 namespace packages are not supported

Development

Setup

git clone https://github.com/cmyui/import-analyzer-py
cd import-analyzer-py
python -m venv .venv
source .venv/bin/activate
pip install -e ".[dev]"

Running tests

# Run with pytest
pytest tests/ -v

# Run with tox (multiple Python versions)
tox

# Run with coverage
tox -e py

Project structure

.
├── import_analyzer/
│   ├── __init__.py          # Public API exports
│   ├── __main__.py          # Entry point for python -m
│   ├── _main.py             # CLI and orchestration
│   ├── _data.py             # Data classes (ImportInfo, ModuleInfo, etc.)
│   ├── _ast_helpers.py      # AST visitors for import/usage collection
│   ├── _detection.py        # Single-file detection logic
│   ├── _autofix.py          # Autofix logic
│   ├── _resolution.py       # Module resolution (resolves imports to files)
│   ├── _graph.py            # Import graph construction
│   ├── _cross_file.py       # Cross-file analysis with cascade detection
│   └── _format.py           # Output formatting
├── tests/
│   ├── detection_test.py
│   ├── aliased_imports_test.py
│   ├── shadowed_imports_test.py
│   ├── scope_analysis_test.py
│   ├── special_imports_test.py
│   ├── type_annotations_test.py
│   ├── autofix_test.py
│   ├── file_operations_test.py
│   ├── cli_test.py
│   ├── resolution_test.py   # Module resolution tests
│   ├── graph_test.py        # Import graph tests
│   ├── cross_file_test.py   # Cross-file analysis tests
│   └── format_test.py       # Output formatting tests
├── pyproject.toml
├── tox.ini
└── .github/workflows/ci.yml

License

MIT