Introduction

RVM gemsets isolate gem installations per project, but switching between gemsets can fail silently when shell integration is broken, .ruby-gemset files are misconfigured, or the gemset was not properly created. The wrong gem versions get loaded, causing Gem::LoadError, unexpected method missing errors, or the application running with stale dependencies.

Symptoms

  • gem list shows wrong gems after rvm use
  • Application fails with cannot load such file for installed gems
  • rvm current shows different gemset than expected
  • bundle install installs gems to wrong gemset
  • .ruby-gemset file ignored when cd-ing into project directory

Debug current state: ```bash rvm current # Expected: ruby-3.2.2@myapp # Actual: ruby-3.2.2@global

gem list | grep rails # Shows Rails 7.0 instead of expected 7.1 ```

Common Causes

  • .ruby-gemset file not present or has wrong name
  • Gemset not created before referencing in .ruby-gemset
  • Shell not sourcing RVM scripts (missing .bashrc / .zshrc entry)
  • RVM not set as default Ruby version
  • Terminal running non-login shell that skips RVM initialization
  • Multiple Ruby version managers (rbenv, asdf) conflicting

Step-by-Step Fix

  1. 1.Verify RVM shell integration:
  2. 2.```bash
  3. 3.# Check if RVM is loaded
  4. 4.type rvm | head -1
  5. 5.# Expected: rvm is a function

# If not a function, fix shell configuration echo '[[ -s "$HOME/.rvm/scripts/rvm" ]] && source "$HOME/.rvm/scripts/rvm"' >> ~/.bashrc source ~/.bashrc

# For zsh echo '[[ -s "$HOME/.rvm/scripts/rvm" ]] && source "$HOME/.rvm/scripts/rvm"' >> ~/.zshrc source ~/.zshrc ```

  1. 1.Create and configure gemset correctly:
  2. 2.```bash
  3. 3.# Create gemset first, then reference it
  4. 4.rvm use ruby-3.2.2
  5. 5.rvm gemset create myapp
  6. 6.rvm use ruby-3.2.2@myapp

# Create .ruby-version and .ruby-gemset in project root echo "ruby-3.2.2" > .ruby-version echo "myapp" > .ruby-gemset

# Verify automatic switching cd .. cd myapp rvm current # Should show: ruby-3.2.2@myapp ```

  1. 1.Fix existing broken gemset:
  2. 2.```bash
  3. 3.# List all gemsets
  4. 4.rvm gemset list

# Delete problematic gemset rvm gemset delete myapp --force

# Recreate cleanly rvm use ruby-3.2.2@myapp --create gem install bundler bundle install

# Verify gem list rvm gemset export myapp.gems # Backup gem list ```

  1. 1.Resolve conflicts with other Ruby managers:
  2. 2.```bash
  3. 3.# Check for rbenv
  4. 4.which ruby
  5. 5.# If it shows ~/.rbenv/shims/ruby, rbenv is taking precedence

# Disable rbenv in shell config (comment out in .bashrc/.zshrc) # eval "$(rbenv init -)" # <-- comment this out

# Ensure RVM is loaded after rbenv is disabled source ~/.bashrc

# Verify RVM ruby which ruby # Should show: ~/.rvm/rubies/ruby-3.2.2/bin/ruby

ruby -v # Should show: ruby 3.2.2 ```

  1. 1.Add verification to project setup script:
  2. 2.```bash
  3. 3.#!/bin/bash
  4. 4.# bin/setup-checks

echo "Checking Ruby environment..."

# Verify RVM is loaded if ! type rvm &>/dev/null; then echo "ERROR: RVM is not loaded. Run: source ~/.rvm/scripts/rvm" exit 1 fi

# Verify correct gemset EXPECTED="ruby-3.2.2@myapp" ACTUAL=$(rvm current) if [ "$ACTUAL" != "$EXPECTED" ]; then echo "WARNING: Wrong gemset. Expected $EXPECTED, got $ACTUAL" echo "Run: rvm use ruby-3.2.2@myapp" exit 1 fi

# Verify critical gems bundle check || bundle install echo "Ruby environment OK" ```

Prevention

  • Use .ruby-version and .ruby-gemset files committed to the repository
  • Add rvm current check to CI/CD pipeline
  • Prefer Bundler's --path or project-local .bundle/ over gemsets for isolation
  • Document RVM setup in project README
  • Use rvm gemset use myapp instead of rvm use to avoid version switching confusion
  • Consider migrating to rbenv + bundler for simpler version management