refactor: code cleanup and improvements (#63)

* test: use bash from PATH for portability

* refactor: rename ContextVar from var_ prefix to ctx_ prefix

Improve naming clarity for module-level ContextVar variables:
- var_root -> ctx_root
- var_parent -> ctx_parent
- var_self -> ctx_self
- var_finding -> ctx_finding

Amp-Thread-ID: https://ampcode.com/threads/T-019c2e4e-7deb-7076-8168-36fbd8141afa
Co-authored-by: Amp <amp@ampcode.com>

* refactor: use dict mapping for comparison operators in transformer

Replace if-elif chain with COMPARISON_OPERATORS dict for better
readability and extensibility.

Amp-Thread-ID: https://ampcode.com/threads/T-019c2e4e-7deb-7076-8168-36fbd8141afa
Co-authored-by: Amp <amp@ampcode.com>

* refactor: improve CLI error handling with proper exception chaining

- Use 'raise SystemExit() from exc' to preserve exception chain
- Add try-except for file reading and JSON parsing errors
- Provide more descriptive error messages

Amp-Thread-ID: https://ampcode.com/threads/T-019c2e4e-7deb-7076-8168-36fbd8141afa
Co-authored-by: Amp <amp@ampcode.com>

* refactor: simplify Slice.find default value assignments

- Use 'or' operator to reduce redundant if statements
- Replace assert with proper JSONPathFindError exception

Amp-Thread-ID: https://ampcode.com/threads/T-019c2e4e-7deb-7076-8168-36fbd8141afa
Co-authored-by: Amp <amp@ampcode.com>

* refactor: reduce Compare subclass boilerplate with _symbol and _operator

- Add _symbol and _operator class attributes to Compare base class
- Move common _get_partial_expression and find to base class
- Subclasses now only define _symbol and _operator attributes
- And/Or retain custom find for short-circuit evaluation semantics

Amp-Thread-ID: https://ampcode.com/threads/T-019c2e4e-7deb-7076-8168-36fbd8141afa
Co-authored-by: Amp <amp@ampcode.com>

* refactor: replace assert with proper TypeError exceptions

- Array.__init__: use TypeError for invalid idx parameter
- Predicate.__init__: use TypeError for invalid expr parameter
- Brace.__init__: use TypeError for invalid expr parameter
- Search.__init__: use TypeError for invalid expr parameter
- Key.__init__: use TypeError for unexpected arguments
- Contains.__init__: use TypeError for invalid parameters
- Not.__init__: use TypeError for invalid parameters

This ensures type checks work even with Python -O optimization.

Amp-Thread-ID: https://ampcode.com/threads/T-019c2e4e-7deb-7076-8168-36fbd8141afa
Co-authored-by: Amp <amp@ampcode.com>

* refactor: final cleanup of assert statements and if-elif chains

- get_begin: replace assert with RuntimeError
- Array.find: simplify control flow, remove unreachable AssertionError
- predicate: merge isinstance checks to remove assert
- func_call: use FUNCTIONS dict mapping instead of if-elif chain

Amp-Thread-ID: https://ampcode.com/threads/T-019c2e4e-7deb-7076-8168-36fbd8141afa
Co-authored-by: Amp <amp@ampcode.com>

* refactor: minor cleanup for naming consistency

- Slice: rename self.end to self.stop to match parameter name
- comparison_expr: use ValueError instead of AssertionError
- doctest: update var_boo to ctx_boo for naming consistency

Amp-Thread-ID: https://ampcode.com/threads/T-019c2e4e-7deb-7076-8168-36fbd8141afa
Co-authored-by: Amp <amp@ampcode.com>

* ci: add Python 3.14 support and update actions/cache to v4

* ci: migrate from PDM to Nix-based workflow and add Python 3.14 support

- Replace PDM setup with custom Nix GitHub Action for CI
- Add new Nix build check job to verify flake builds
- Update GitHub Actions: checkout@v6, actions/cache@v5, codecov-action@v5
- Add Nix store and Cargo dependency caching
- Switch from pre-commit to prek for linting
- Update flake inputs to use nixpkgs-unstable directly
- Add Python 3.14 to test matrix (3.10-3.14)
- Update dependency versions (babel, charset-normalizer, coverage, etc.)
- Add make init step before running tests

* ci: update actions/cache to v4

---------

Co-authored-by: Amp <amp@ampcode.com>

Author: linw1995

.github/actions/setup-nix/action.yaml

@@ -0,0 +1,34 @@
+name: "Setup Nix Environment"
+description: ""
+runs:
+  using: composite
+  steps:
+    - uses: nixbuild/nix-quick-install-action@v33
+      with:
+        nix_conf: |
+          keep-env-derivations = true
+          keep-outputs = true
+    - name: Restore and save Nix store
+      uses: nix-community/cache-nix-action@v6
+      with:
+        primary-key: nix-${{ runner.os }}-${{ hashFiles('**/*.nix', '**/flake.lock') }}
+        restore-prefixes-first-match: nix-${{ runner.os }}-
+        gc-max-store-size-linux: 15G
+
+    - name: Cache Cargo dependencies
+      uses: actions/cache@v4
+      with:
+        path: |
+          ~/.cargo/registry
+          ~/.cargo/git
+          target
+        key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
+        restore-keys: |
+          ${{ runner.os }}-cargo-
+
+    - name: Setup nix develop env
+      shell: bash
+      run: |
+        echo 'use flake' >.envrc
+    - uses: HatsuneMiku3939/direnv-action@v1
+    # and avoid develop env being gc

.github/workflows/test.yml

@@ -13,39 +13,44 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v1
-      - name: Set up PDM
-        uses: pdm-project/setup-pdm@v3
+      - uses: actions/checkout@v6
+      - uses: ./.github/actions/setup-nix
+      - name: Cache pre-commit hooks
+        uses: actions/cache@v5
         with:
-          python-version: 3.13
-          version: 2.19.2
-      - name: Cache Nox Virtualenvs
-        uses: actions/cache@v1
-        with:
-          path: .nox
-          key: ${{ runner.os }}-nox-${{ hashFiles('**/pdm.lock') }}
-          restore-keys: ${{ runner.os }}-nox
-      - name: Install nox
-        run: |
-          pip install nox
-          pdm config python.use_venv true
-      - uses: pre-commit/action@v2.0.0
-        env:
-          SKIP: export_requirements_txt
+          path: ~/.cache/prek
+          key: prek-v1|${{ runner.os }}|${{ runner.arch }}|${{ hashFiles('**/.pre-commit-config.yaml') }}
+
+      - name: Run pre commit hooks on all files
+        run: prek run --all-files
+
+  nix-build-check:
+    needs:
+      - lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+      - uses: ./.github/actions/setup-nix
+
+      - name: Build nix package
+        run: nix build --profile default
+        # use --profile default to avoid dependencies being gc
+
+      - name: Run nix flake check
+        run: nix flake check --all-systems
+
   test:
     needs: lint
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.10", "3.11", "3.12", "3.13"]
+        python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
     steps:
-      - uses: actions/checkout@v1
-      - name: Set up PDM
-        uses: pdm-project/setup-pdm@v3
-        with:
-          python-version: ${{ matrix.python-version }}
+      - uses: actions/checkout@v6
+      - uses: ./.github/actions/setup-nix
+
       - name: Cache Nox Virtualenvs
-        uses: actions/cache@v1
+        uses: actions/cache@v4
         with:
           path: .nox
           key: ${{ runner.os }}-${{ matrix.python-version }}-nox-${{ hashFiles('**/pdm.lock') }}
@@ -56,9 +61,10 @@ jobs:
           pdm config python.use_venv true
       - name: Test with coverage
         run: |
+          make PYTHON=${{ matrix.python-version }} init
           make PYTHON=${{ matrix.python-version }} cov
       - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@v2
+        uses: codecov/codecov-action@v5
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           flags: main,unittest,${{ matrix.python-version }}

flake.lock

@@ -1,7 +1,7 @@
 {
   inputs = {
     dream2nix.url = "github:nix-community/dream2nix";
-    nixpkgs.follows = "dream2nix/nixpkgs";
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
   };
 
   outputs = {
@@ -40,13 +40,14 @@
         inputsFrom = [self.packages.${system}.default.devShell];
 
         packages = with pkgs; [
-          pre-commit
+          prek
           python3Packages.nox
 
           python310
           python311
           python312
           python313
+          python314
         ];
       };
     });

flake.nix

@@ -14,16 +14,22 @@ def cli(args: argparse.Namespace) -> None:
     try:
         jp = parse(args.expression)
     except JSONPathError as exc:
-        sys.exit(str(exc))
+        raise SystemExit(str(exc)) from exc
 
     if args.file:
         file_path = Path(args.file)
-        with file_path.open() as f:
-            data = json.load(f)
+        try:
+            with file_path.open() as f:
+                data = json.load(f)
+        except (OSError, json.JSONDecodeError) as exc:
+            raise SystemExit(f"Error reading {file_path}: {exc}") from exc
     elif not sys.stdin.isatty():
-        data = json.load(sys.stdin)
+        try:
+            data = json.load(sys.stdin)
+        except json.JSONDecodeError as exc:
+            raise SystemExit(f"Invalid JSON from stdin: {exc}") from exc
     else:
-        sys.exit("JSON file is needed.")
+        raise SystemExit("JSON file is needed.")
 
     json.dump(jp.find(data), sys.stdout, indent=2, ensure_ascii=args.ensure_ascii)
     sys.stdout.write("\n")