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resolve-project-references

Testing & Quality
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Guide for interpreting ResolveProjectReferences time in MSBuild performance summaries. Activate when ResolveProjectReferences appears as the most expensive target and developers are trying to optimize it directly. Explains that the reported time includes wait time for dependent project builds and is misleading. Guides users to focus on task self-time instead. Do not activate for general build performance — use build-perf-diagnostics instead.

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Source SKILL.md: https://github.com/majiayu000/claude-skill-registry/blob/HEAD/skills/development/resolve-project-references/SKILL.md

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Misleading ResolveProjectReferences Time

The Problem

When reviewing the Target Performance Summary from a diagnostic build log, ResolveProjectReferences often appears as the single most expensive target — sometimes consuming 50-80% of total build time. This is misleading.

Why It's Misleading

The reported time for ResolveProjectReferences includes waiting for dependent projects to build while the MSBuild node is yielded (see dotnet/msbuild#3135). During this wait, the node may be doing useful work on other projects.

The target itself does very little work — it just triggers the build of referenced projects and waits for them to complete. The "time" attributed to it is wall-clock wait time, not CPU work.

Correct Diagnosis

  1. Use Task Performance Summary instead of Target Performance Summary for an accurate picture of where time is actually spent
  2. Focus on self-time of actual tasks: Csc (compilation), ResolveAssemblyReference (RAR), Copy, etc.
  3. Do not optimize ResolveProjectReferences directly — optimize the targets/tasks it's waiting on

How to Get Task Performance Summary

dotnet msbuild build.binlog -noconlog -fl "-flp:v=diag;logfile=full.log;performancesummary"
grep "Task Performance Summary" -A 50 full.log

What to Optimize Instead

Look at the tasks consuming the most cumulative time:

  • Csc: see build-perf-diagnostics skill (Section 2: Roslyn Analyzers)
  • ResolveAssemblyReference: see build-perf-diagnostics skill (Section 1: RAR)
  • Copy: see build-perf-diagnostics skill (Section 4: File I/O)
  • Serialization bottlenecks: see build-parallelism skill