RahulGautamSinghnpm problems and workarounds
Invalid lock file (npm ci fails)
Unfortunately, npm itself sometimes generates invalid lock files which fail npm ci.
Try adding "postUpdateOptions": ["npmInstallTwice"] to tell Renovate run any npm install command (which is used to update lock files) twice.
This is less efficient than running npm once, but has been known to fix most problems of this type.
Renovate already runs npm install twice during lock file maintenance, because regenerating a lock file from scratch is known to need a second pass.
If this npm bug remains unfixed, and it becomes too frequent for Renovate users, then we may need to modify Renovate to do this by default. Please post feedback to the Renovate repository "Discussions" if you're needing to use this feature frequently or widely.
Yarn
Version Selection / Installation
If Renovate detects a packageManager setting for Yarn in package.json then it will use Corepack to install Yarn.
HTTP Proxy Support
Yarn itself does not natively recognize/support the HTTP_PROXY and HTTPS_PROXY environment variables.
You can configure RENOVATE_X_YARN_PROXY=true as an environment variable to enable configuring of Yarn proxy (e.g. if you cannot configure these proxy settings yourself in ~/.yarnrc.yml).
If set, and Renovate detects Yarn 2+, and one or both of those variables are present, then Renovate will run commands like yarn config set --home httpProxy http://proxy prior to executing yarn install.
This will result in the ~/.yarnrc.yml file being created or modified with these settings, and the settings are not removed afterwards.
Configuration/conversion of NO_PROXY to Yarn config is not supported.