load_dependencies_into_env: Load and Install Package Dependencies from a DESCRIPTION File

In test.assessr: Assessing Package Test Reliability and Quality

Load and Install Package Dependencies from a DESCRIPTION File

Description

Reads a package's 'DESCRIPTION' file, parses dependency fields ('Depends', 'Imports', 'Suggests'), installs missing packages or those that do not satisfy version constraints, loads namespaces, and—for packages listed under **Depends**—imports their exported symbols into a provided evaluation environment. This makes bare function names visible when evaluating code in environments that do not inherit from '.GlobalEnv' (e.g., environments with 'baseenv()' as parent).

Usage

load_dependencies_into_env(pkg_source_path, env)

Arguments

pkg_source_path	'character(1)'. Path to a package source directory containing a 'DESCRIPTION' file.
env	An environment into which exported symbols from packages listed in the **Depends** field will be imported. This allows code evaluated in 'env' to resolve functions from those packages using bare names without requiring attachment on the search path.

Details

This function avoids calling 'installed.packages()' because that function scans all installed packages and is slow on some platforms (especially Windows and network filesystems). Using 'requireNamespace()' is the recommended approach for checking whether a package is installed and usable. 'packageDescription()' is used only on a small set of packages when version information or priority metadata is needed.

When evaluating code in environments that do not inherit from '.GlobalEnv', attaching packages does not necessarily make their exported symbols available. For this reason, exports from packages listed under 'Depends' are explicitly imported into the target environment.

Value

Invisibly returns 'TRUE' on success.

Behavior

1. **Dependency parsing** Parses entries of the form '"pkg"' or '"pkg (op version)"', where the operator 'op' is one of '>=', '>', '<=', '<', '=='. HTML-escaped forms ('&gt;', '&lt;') are normalized.

2. **Dependency fields** Dependencies are extracted from the 'Depends', 'Imports', and 'Suggests' fields. The 'Depends: R (>= x.y.z)' entry is ignored for installation purposes, but the R version constraint is validated.

3. **Base/recommended packages** Unlike tools such as 'R CMD check', this function **does not skip** recommended or base packages (e.g., 'graphics', 'stats', 'utils', 'grDevices') because packages listed in 'Depends:' must be made visible in the target evaluation environment even when its parent is 'baseenv()'. If a package is already installed with R, no installation is attempted.

4. **Availability and version checks** Package presence is determined via 'requireNamespace(pkg, quietly = TRUE)' instead of 'installed.packages()', for performance and portability. If a version constraint is declared, the installed version (from 'packageDescription(pkg, fields = "Version")') is compared using 'utils::compareVersion()'.

5. **Package installation** - For constraints of the form '>=' or '>': 'install.packages()' is used (latest version is assumed valid). - For '<=', '<', or '==': 'remotes::install_version()' is used to install an exact version.

6. **Loading behavior** Each dependency is namespace-loaded via 'loadNamespace()'. Packages that appear in the 'Depends' field have all their **exported symbols imported** into the supplied 'env'. This makes calls such as 'plot()', 'lm()', or 'head()' resolve correctly inside environments whose parent is not '.GlobalEnv'.

test.assessr documentation built on March 3, 2026, 1:06 a.m.