llama-dev: add changelog generation command (#19925)

Author: masci

CHANGELOG.md

@@ -1,5 +1,7 @@
 # ChangeLog
 
+<!--- generated changelog --->
+
 ## [2025-09-15]
 
 ### `llama-index-core` [0.14.2]

llama-dev/llama_dev/release/__init__.py

@@ -1,5 +1,6 @@
 import click
 
+from .changelog import changelog
 from .check import check
 
 
@@ -9,3 +10,4 @@ def release():
 
 
 release.add_command(check)
+release.add_command(changelog)

llama-dev/llama_dev/release/changelog.py

@@ -0,0 +1,110 @@
+import json
+import re
+import subprocess
+from datetime import date
+
+import click
+
+from llama_dev.utils import find_all_packages, get_changed_packages, load_pyproject
+
+
+def run_command(command: str) -> str:
+    """Helper to run a shell command and return the output."""
+    result = subprocess.run(command, shell=True, capture_output=True, text=True)
+    if result.returncode != 0:
+        raise RuntimeError(f"Command failed: {command}\n{result.stderr}")
+    return result.stdout.strip()
+
+
+@click.command(short_help="Generate the changelog from the previous release tag")
+@click.option(
+    "--dry-run",
+    is_flag=True,
+    help="Show the changelog text without altering the CHANGELOG.md file",
+)
+@click.pass_obj
+def changelog(obj: dict, dry_run: bool) -> None:
+    """
+    Generate the changelog in markdown syntax.
+
+    \b
+    This command will:
+        - get the list of GitHub PRs that happened since the last release tag
+        - create a bullet list in Markdown syntax using the PR titles
+        - group the changes per package, depending on the path that changed
+    """  # noqa
+    console = obj["console"]
+    repo_root = obj["repo_root"]
+    all_packages = find_all_packages(repo_root)
+
+    try:
+        # Get the latest git tag
+        latest_tag = run_command('git describe --tags --match "v[0-9]*" --abbrev=0')
+        console.print(f"Generating changelog since tag '{latest_tag}'...")
+
+        # Get commits since the last tag and extract PR numbers
+        log_output = run_command(f'git log {latest_tag}..HEAD --pretty="format:%H %s"')
+        pr_numbers = set()
+        pr_pattern = re.compile(r"\(#(\d+)\)")
+        for line in log_output.splitlines():
+            match = pr_pattern.search(line)
+            if match:
+                pr_numbers.add(match.group(1))
+
+        if not pr_numbers:
+            raise click.ClickException("No pull requests found since the last tag.")
+
+        package_prs = {}
+        package_versions = {}
+
+        with click.progressbar(sorted(pr_numbers), label="Fetching PR details") as bar:
+            for pr_number in bar:
+                try:
+                    pr_json_str = run_command(
+                        f"gh pr view {pr_number} --json number,title,url,files"
+                    )
+                    pr_data = json.loads(pr_json_str)
+                    files = [repo_root / f["path"] for f in pr_data.get("files", [])]
+
+                    changed_packages = get_changed_packages(files, all_packages)
+                    for pkg in changed_packages:
+                        pkg_name = pkg.name
+                        if pkg_name not in package_prs:
+                            package_prs[pkg_name] = []
+                            package_data = load_pyproject(pkg)
+                            ver = package_data["project"]["version"]
+                            package_versions[pkg_name] = ver
+
+                        package_prs[pkg_name].append(pr_data)
+
+                except Exception as e:
+                    console.print(
+                        f"Warning: Could not fetch details for PR #{pr_number}. {e}",
+                        style="error",
+                    )
+
+        # Generate the markdown output
+        changelog_text = f"<!--- generated changelog --->\n\n## [{date.today().strftime('%Y-%m-%d')}]"
+        sorted_pkgs = sorted(package_prs.keys())
+        for pkg in sorted_pkgs:
+            changelog_text += f"\n\n### {pkg} [{package_versions[pkg]}]\n"
+            prs = sorted(package_prs[pkg], key=lambda p: p["number"])
+            for pr in prs:
+                changelog_text += f"- {pr['title']} ([#{pr['number']}]({pr['url']}))"
+
+        if dry_run:
+            click.echo(changelog_text)
+        else:
+            with open(repo_root / "CHANGELOG.md", "r+") as f:
+                content = f.read()
+                f.seek(0)
+                f.truncate()
+                f.write(
+                    content.replace("<!--- generated changelog --->", changelog_text)
+                )
+
+    except FileNotFoundError:
+        click.ClickException(
+            "Error: 'gh' command not found. "
+            "Please ensure it's installed and in your PATH."
+        )