Comparison with MSBuild

Invoke-Build scripts are designed to be conceptually similar to MSBuild. They are PowerShell, not XML, and they use different tools. But build concepts and script structure are very similar.

MSBuild	Invoke-Build
Default project *proj	Default script *.build.ps1
DefaultTargets	The . task or the first task
InitialTargets	Script code and Enter-Build
Properties	Script and environment variables
Import	Dot-source or invoke
Target	Task
Condition	-If
Inputs, Outputs	-Inputs, -Outputs, -Partial
DependsOnTargets	-Jobs, referenced tasks
Tasks	-Jobs, script blocks
AfterTargets, BeforeTargets	-After, -Before

MSBuild targets consist of calls to built-in or external tools. Invoke-Build tasks consist of PowerShell script blocks. Unlike MSBuild, Invoke-Build does not provide numerous tools for scripts, PowerShell does this.

Invoke-Build task jobs combine two MSBuild features: referenced targets and own target tasks. The parameter Jobs is a list of task references (analogue of DependsOnTargets) and script blocks (analogue of MSBuild tasks). Thus, jobs define classic MSBuild scenarios (referenced tasks first, own scripts second) and new scenarios with referenced tasks after or even between script jobs.

Invoke-Build "properties" are usual PowerShell script variables and parameters, just like MSBuild properties defined in XML scripts (variables) and properties that come from command lines (parameters). MSBuild also deals with environment variables using the same syntax. In contrast, Invoke-Build scripts either use environment variables as $env:Name or get them by the helper property.

MSBuild allows ignoring some errors and triggering actions on errors. Some Invoke-Build tasks are allowed to fail without breaking the build and then downstream tasks may analyse these errors.

Invoke-Build allows definition of new tasks with specific features and new parameters, not necessarily designed for build scenarios. E.g. check for check-lists, repeat for schedules, test for testing, and etc. MSBuild presumably does not directly support definition of new targets.

DefaultTargets and InitialTargets

The exact equivalent of MSBuild's DefaultTargets is the special Invoke-Build task . (dot), the default task. All its referenced tasks are default tasks.

The partial equivalent of MSBuild's InitialTargets is Invoke-Build script scope code and the Enter-Build block. Consider using Enter-Build if the code does anything significant.

The exact equivalent of MSBuild's InitialTargets would be yet another task with a special name. But the practice shows that this is not really needed.

AfterTargets and BeforeTargets with Condition

AfterTargets and BeforeTargets of MSBuild targets with Condition are always invoked, even if the condition is false. In contract, After and Before of Invoke-Build tasks with If are not invoked if the condition is false. In other words, these two Invoke-Build scripts are identical, unlike equivalent MSBuild scripts:

# script 1
task Task1 {...}
task Task2 -If {...} Task1, {...}

# script 2
task Task1 -Before Task2 {...}
task Task2 -If {...} {...}

See the task condition_and_targets in Acknowledged.build.ps1.