Implementation:Langchain ai Langchain Git Log Release Notes

Overview

Concrete tool for generating release notes from Git history, provided by the release-notes job in _release.yml using git log --format="%s".

Description

The release-notes job runs after the build job and produces the release body in two steps:

Step 1 -- Check Tags (lines 116-171): Computes the previous release tag for the package:

• For pre-release versions (containing a hyphen): looks for a tag matching the base version, then falls back to the most recent stable release tag.
• For stable versions: computes the previous patch version tag (e.g., langchain-core==1.2.10 for version 1.2.11). If the patch is 0, falls back to the most recent tag.
• Validates the computed previous tag exists in the Git repository.
• Aborts if the new tag would be identical to the previous tag.

Step 2 -- Generate Release Body (lines 172-193): Runs git log scoped to the package directory to collect commit subjects, prefixed with a preamble.

The job uses sparse checkout and fetch-depth: 0 to ensure full commit history is available while only checking out files for the relevant package directory.

Usage

This job runs automatically as part of the release pipeline. Its output (release-body) is consumed by the mark-release job to populate the GitHub Release description.

Code Reference

Source Location: .github/workflows/_release.yml (lines 99-193)

Previous Tag Computation (stable version):

# Compute previous patch version tag
PREV_TAG="$PKG_NAME==${VERSION%.*}.$(( ${VERSION##*.} - 1 ))"
# If patch is 0, look for latest tag
if [ -z "$PREV_TAG" ]; then
  REGEX="^$PKG_NAME==\\d+\\.\\d+\\.\\d+\$"
  PREV_TAG=$(git tag --sort=-creatordate | (grep -P $REGEX || true) | head -1)
fi

Previous Tag Computation (pre-release version):

BASE_VERSION=${VERSION%%-*}
REGEX="^$PKG_NAME==$BASE_VERSION\$"
PREV_TAG=$(git tag --sort=-creatordate | (grep -P "$REGEX" || true) | head -1)
# Fallback to latest stable if no base version tag
if [ -z "$PREV_TAG" ]; then
  REGEX="^$PKG_NAME==\\d+\\.\\d+\\.\\d+\$"
  PREV_TAG=$(git tag --sort=-creatordate | (grep -P "$REGEX" || true) | head -1)
fi

Release Body Generation:

PREAMBLE="Changes since $PREV_TAG"
if [ -z "$PREV_TAG" ] || [ "$PREV_TAG" = "$PKG_NAME==0.0.0" ]; then
  PREAMBLE="Initial release"
  PREV_TAG=$(git rev-list --max-parents=0 HEAD)
fi
{
  echo 'release-body<<EOF'
  echo $PREAMBLE
  echo
  git log --format="%s" "$PREV_TAG"..HEAD -- $WORKING_DIR
  echo EOF
} >> "$GITHUB_OUTPUT"

Invocation: Automatic, as part of the release pipeline. Depends on build job outputs (pkg-name, version).

I/O Contract

Direction	Name	Type	Description
Input	PKG_NAME	string	Package name from the build job (e.g., langchain-core)
Input	VERSION	string	Version string from the build job (e.g., 1.2.11)
Input	working-directory	string	Package directory for scoping the git log
Input	Git history	Repository	Full commit history (fetched with fetch-depth: 0)
Output	tag	string	The new release tag (e.g., langchain-core==1.2.11)
Output	prev-tag	string	The previous release tag (e.g., langchain-core==1.2.10)
Output	release-body	string	The formatted release notes body

Usage Examples

Example 1: Typical release notes output

Changes since langchain-core==1.2.10

fix(core): resolve type hinting issue in vector store
feat(core): add streaming support to chat model base
chore(core): update tenacity dependency range

Example 2: First release of a new package

Initial release

feat(deepseek): add initial DeepSeek chat model integration
feat(deepseek): add embeddings support
docs(deepseek): add README and usage examples

Example 3: Running the git log command locally

PKG_NAME="langchain-core"
PREV_TAG="langchain-core==1.2.10"
WORKING_DIR="libs/core"

git log --format="%s" "$PREV_TAG"..HEAD -- $WORKING_DIR

Related Pages

• Principle:Langchain_ai_Langchain_Release_Notes_Generation