generate-gh-release-notes.py

Overview

`generate-gh-release-notes.py` is a Python utility script designed to automate the extraction and conversion of changelog entries from a specific pytest release version. It reads the changelog in reStructuredText (RST) format, extracts the relevant entries for the specified version, converts these entries into Markdown format, and writes the output to a file. This Markdown file is suitable for use as the release notes in a GitHub Release during deployment workflows.

The script depends on `pandoc` (via the `pypandoc` Python wrapper) to perform the RST-to-Markdown conversion, as GitHub Releases require Markdown-formatted notes. It is intended to be run as a command-line tool, taking the version string and output filename as arguments.

Detailed Explanation

Dependencies and Requirements

Python 3.6+
pandoc installed on the system (required by pypandoc)
Python package pypandoc
The changelog file is expected at: ../doc/en/changelog.rst relative to this script

Functions

`extract_changelog_entries_for(version: str) -> str`

**Purpose:** Extracts the changelog entries corresponding to a specific pytest version from the RST changelog file.

**Parameters:**

version (str): The semantic version string of pytest (e.g., "7.1.2") whose changelog entries need to be extracted.

**Returns:**

str: The complete changelog section for the specified version, including the title line and all subsequent lines until the next version section starts.

**Description:**

Reads the changelog file (changelog.rst).
Uses a regular expression to identify version headings matching the pattern:
pytest () e.g., pytest 7.1.2 (2023-01-30).
Starts capturing lines once the specified version heading is found.
Stops capturing when the next version heading is encountered.
Returns the captured lines joined as a single string.

**Usage Example:**

entries = extract_changelog_entries_for("7.1.2")
print(entries)

`convert_rst_to_md(text: str) -> str`

**Purpose:** Converts a string containing RST-formatted text into Markdown format.

**Parameters:**

text (str): The RST text to convert.

**Returns:**

str: The converted Markdown text.

**Description:**

Uses the pypandoc.convert_text function with the following options:
- Input format: rst
- Output format: md (Markdown)
- Extra argument: --wrap=preserve to maintain original line wrapping.
Asserts that the returned value is a string for safety.

**Usage Example:**

rst_text = "pytest 7.1.2 (2023-01-30)\n=======================\n- Fixed bug #123"
md_text = convert_rst_to_md(rst_text)
print(md_text)

`main(argv: Sequence[str]) -> int`

**Purpose:** Command-line entry point for running the script.

**Parameters:**

argv (Sequence[str]): List of command-line arguments. Expected format:
["generate-gh-release-notes.py", <VERSION>, <OUTPUT_FILE>]

**Returns:**

int: Exit code (0 on success, 2 on incorrect usage).

**Behavior:**

Validates argument count.
Extracts the version and output filename from argv.
Calls extract_changelog_entries_for to get the RST changelog for the version.
Converts the RST changelog to Markdown using convert_rst_to_md.
Writes the Markdown output to the specified file.
Prints progress and completion messages.

**Usage from Command Line:**

python generate-gh-release-notes.py 7.1.2 release-notes.md

Important Implementation Details

Regex for Version Detection:
The regular expression pytest (\d\.\d+\.\d+\w*) \(\d{4}-\d{2}-\d{2}\) matches version headings strictly formatted as:
pytest <major>.<minor>.<patch><optional_letter> (YYYY-MM-DD)
This makes the script sensitive to changelog formatting consistency.
Dependency on External Tool (pandoc):
The script requires that pandoc is installed on the host system because pypandoc is a thin wrapper around it. Without pandoc, the conversion step will fail.
File Path Assumption:
The changelog file location is hardcoded relative to the script location: it assumes the changelog lives at ../doc/en/changelog.rst. This means the script should be run in a context where this relative path is valid.

Interaction With Other System Components

Changelog Source:
The script depends on the changelog file (changelog.rst) maintained as part of the documentation source tree.
Deployment Workflow:
Output Markdown files generated by this script are incorporated into GitHub Releases, which are created during deployment. The deployment workflow (e.g., workflows/deploy.yml) uses the Markdown release notes generated here for proper release documentation on GitHub.
Toolchain Dependency:
The script ties together the Python environment and the external pandoc tool, bridging format conversion between documentation and GitHub requirements.

Example Workflow

Run the script specifying a version and output filename:

python generate-gh-release-notes.py 7.1.2 release-notes.md

The script extracts the changelog section for version 7.1.2 from the RST changelog.
Converts the extracted RST text to Markdown.
Writes the Markdown output to release-notes.md.
The generated release-notes.md is then used in the GitHub Release creation process.

Visual Diagram

flowchart TD
    A[Start: main(argv)] --> B{Check argv length == 3?}
    B -- No --> C[Print usage message]
    C --> Z[Exit with code 2]
    B -- Yes --> D[Parse version & filename]
    D --> E[extract_changelog_entries_for(version)]
    E --> F[Read changelog.rst]
    F --> G[Scan lines for version header]
    G --> H[Collect lines for version]
    H --> I[Return RST text]
    I --> J[convert_rst_to_md(RST text)]
    J --> K[Call pypandoc with pandoc]
    K --> L[Return Markdown text]
    L --> M[Write Markdown to filename]
    M --> N[Print done message]
    N --> Z[Exit with code 0]

Summary

`generate-gh-release-notes.py` is a focused utility script that automates the extraction and conversion of changelog entries from pytest's RST changelog into Markdown format for GitHub releases. It uses regex-based parsing to isolate relevant changelog sections and leverages `pandoc` for accurate format conversion, fitting seamlessly into the deployment workflow to provide well-formatted release notes.