When working with Debian-based systems, you'll occasionally encounter scenarios where package dependencies create version conflicts. Imagine this situation:

# Current state:
Package B installed: v2.1
Package A requires: B (>2.0)

# Repository contains:
Package B available: v2.2

While your system technically meets the dependency requirement (2.1 > 2.0), APT will still try to upgrade to the newest available version (2.2) during installation.

The most straightforward method is to use APT's built-in flag:

sudo apt-get install --no-upgrade package-A

This tells APT to:

• Install package A
• Skip any upgrades to already-installed packages
• Only install missing dependencies

For more permanent control, use package pinning:

# Hold the current version of package B
sudo apt-mark hold package-B

# Now install package A
sudo apt-get install package-A

# Optional: remove the hold later
sudo apt-mark unhold package-B

Create /etc/apt/preferences.d/package-B with:

Package: package-B
Pin: version 2.1*
Pin-Priority: 1001

This configuration:

• Locks package B at version 2.1
• Sets priority higher than standard packages (1001)
• Overrides repository versions

A common scenario involves PHP extensions:

# Current PHP version: 7.4
# Repository has PHP 8.0
# Want to install a package requiring php7.4-*

sudo apt-mark hold php7.4
sudo apt-get install --no-upgrade package-requiring-php

Remember that preventing upgrades might:

• Leave security vulnerabilities unpatched
• Cause future compatibility issues
• Require manual intervention for subsequent updates

Always test in a development environment before applying these changes to production systems.

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When working with Debian-based systems, we often encounter this scenario:

sudo apt-get install packageA
The following packages will be upgraded:
  packageB

Even though our current version of packageB (say 2.1) already satisfies packageA's dependency requirement (>2.0), APT insists on upgrading to the latest version (2.2) available in repositories.

By default, APT will:

• Resolve all dependencies to their newest available versions
• Consider recommended packages as dependencies (configurable)
• Upgrade all packages in the dependency chain to maintain consistency

1. Using --no-upgrade

The most straightforward approach:

sudo apt-get install packageA --no-upgrade

However, this has limitations - it prevents ALL upgrades during installation, not just specific dependencies.

2. Pinning Specific Package Versions

More surgical approach using apt-mark:

sudo apt-mark hold packageB
sudo apt-get install packageA
sudo apt-mark unhold packageB

Or using /etc/apt/preferences.d/:

Package: packageB
Pin: version 2.1*
Pin-Priority: 1001

3. Using aptitude's Interactive Mode

Aptitude provides more granular control:

sudo aptitude install packageA

Then press 'n' to reject the upgrade proposal and find alternative solutions.

4. Forcing Specific Dependency Versions

Using apt-get with version pinning:

sudo apt-get install packageA packageB=2.1

Creating a Local Minimal Repository

For critical production systems:

mkdir ~/local-repo
cd ~/local-repo
apt-get download packageB=2.1
sudo dpkg-scanpackages . /dev/null | gzip -9c > Packages.gz

Then add to /etc/apt/sources.list:

deb [trusted=yes] file:/home/user/local-repo ./

Using equivs for Virtual Packages

When you need to fake dependency satisfaction:

sudo apt-get install equivs
equivs-control packageB-virtual
# Edit the control file
equivs-build packageB-virtual
sudo dpkg -i packageB-virtual.deb

• Partial upgrades may break system consistency
• Held packages might conflict with security updates
• Manual version pinning requires maintenance

1. Always test in a staging environment first
2. Document all version constraints applied
3. Monitor security advisories for held packages
4. Consider using containers for isolation