Compress snapshot file

[ofekby]

This pull request updates the snapshot file format in Snaplint from plain JSON to gzip-compressed JSON (.json.gz). The change affects the CLI, core snapshot logic, documentation, and tests to ensure all snapshot files are handled as compressed files for improved efficiency and compatibility.

Snapshot file format migration:

• All references to snapshot files in the codebase, documentation, and tests are updated from .json to .json.gz to indicate gzip compression. This includes default paths, help text, and file handling logic. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14]

Snapshot read/write logic:

• Snapshot writing and reading functions in src/snaplint/snapshot.py now use gzip compression and decompression, respectively. File I/O is switched to binary mode, and error handling for gzip files is added. [1] [2] [3] [4]

Documentation updates:

• The README.md is updated to clarify that snapshots are now stored as gzip-compressed JSON files, with all examples and explanations reflecting the new .json.gz extension. [1] [2] [3]

Test suite updates:

• All relevant tests are updated to use gzip when reading and writing snapshot files, and to expect the .json.gz extension. This ensures tests validate the new compressed format. [1] [2] [3] [4] [5] [6]

Version bump:

• The project version is incremented from 0.5.0 to 0.6.0 in pyproject.toml to reflect this breaking change.

[Copilot]

Pull request overview

This PR migrates the snapshot file format from plain JSON (.json) to gzip-compressed JSON (.json.gz) to improve storage efficiency. This is a breaking change appropriately reflected by bumping the version from 0.5.0 to 0.6.0.

Key changes:

• Updated snapshot read/write functions to use gzip compression and binary file I/O
• Modified all file paths, help text, and documentation to use .json.gz extension
• Updated test suite to handle gzip-compressed snapshots

Reviewed changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/snaplint/snapshot.py	Added gzip compression to write_snapshot() and decompression to read_snapshot(), changed I/O to binary mode, added gzip.BadGzipFile error handling
src/snaplint/cli.py	Updated default snapshot paths to use .json.gz, changed file open modes to binary ('wb'/'rb'), updated help text
tests/test_cli.py	Added gzip import, updated snapshot file fixture path, modified snapshot validation to use gzip.open()
tests/test_e2e.py	Added gzip import, updated all snapshot file paths to .json.gz, modified snapshot reading to use gzip.open()
README.md	Updated documentation to reflect gzip-compressed format and .json.gz extension
pyproject.toml	Bumped version from 0.5.0 to 0.6.0
uv.lock	Updated version reference

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[Copilot]

The error handling should also catch UnicodeDecodeError separately to provide a clearer error message when the gzip file decompresses successfully but contains invalid UTF-8 data. Currently, it would be caught by the generic Exception handler which gives a less specific error message. Consider adding:

except UnicodeDecodeError as e:
    raise SnapshotReadError(f"Invalid UTF-8 encoding in snapshot file: {e}") from e

between the gzip.BadGzipFile and json.JSONDecodeError handlers.

Suggested change

	raise SnapshotReadError(f"Invalid gzip file: {e}") from e
	raise SnapshotReadError(f"Invalid gzip file: {e}") from e
	except UnicodeDecodeError as e:
	raise SnapshotReadError(f"Invalid UTF-8 encoding in snapshot file: {e}") from e