flow-tracing

Flow Tracing

Trace dependency flow across .NET repositories through the VMR pipeline. Two workflows:

1. Cross-repo flow trace: Has a change from repo A reached repo B? → Use Steps 1-4 below (reads GitHub files + maestro MCP directly)
2. SDK version trace: What component SHA is in a specific SDK version? → Run Get-SdkVersionTrace.ps1 (handles version decoding, build lookup, and servicing topology automatically)

Cross-Repo Flow Trace

Question: "Has change X from repo A reached repo B?"

Step 1: Resolve the Source Change

Identify the merge commit SHA in repo A from the PR number, issue number, commit SHA, or description the user provides. If the PR isn't merged yet, stop — the change hasn't entered the pipeline.

Step 2: Check VMR Intake (source-manifest.json)

⚠️ Internal branches (internal/release/*) exist only on AzDO, not GitHub. Use the AzDO REST API to read files. See references/internal-vmr.md.

Read src/source-manifest.json from dotnet/dotnet on the target VMR branch (usually main or release/*). This file is the authoritative record of what the VMR has actually consumed — subscription status reflects Maestro's bookkeeping, but the manifest reflects reality. Find the entry for repo A — the commitSha field shows the latest commit the VMR has consumed.

Determine if the change is included (try in order):

1. Date comparison (fastest): If the VMR commit date is months after the PR merge date, it's included.
2. Compare API: Use GitHub compare endpoint if dates are close.
3. Commit history walk: List recent commits if compare is unavailable.

If repo A's SHA in source-manifest is not past the merge commit → the change hasn't reached the VMR yet. Check for an open forward flow PR from repo A into dotnet/dotnet.

⚠️ 2xx/3xx bands: Only the 1xx branch source-builds all components. If tracing to a 2xx/3xx branch, runtime/aspnetcore won't appear in source-manifest — they're consumed as prebuilts from 1xx. See references/servicing-topology.md.

Step 3: Check Downstream Delivery (repo B)

If the VMR has the change, check if it has flowed to repo B:

⚠️ eng/Version.Details.xml is the file you want — it contains source dependency entries with Sha fields. Do NOT use eng/Versions.props (that has NuGet package versions, not source SHAs).

1. Check subscription health for repo B using maestro MCP.
2. If current: The change has reached repo B. Confirm by reading eng/Version.Details.xml in repo B.
3. If stale: Read eng/Version.Details.xml in repo B — the dotnet/dotnet entry's Sha is the VMR commit repo B last consumed. Check src/source-manifest.json at that SHA for repo A's commitSha. If it's past the merge commit, the change reached repo B despite the stale subscription.
4. If stale AND change not in consumed VMR SHA: Change is in the VMR but hasn't flowed to repo B. Suggest flow-analysis skill for diagnosis.

Step 4: Report

Summarize the trace chain:

• "✅ roslyn#80873 merged at abc123 → VMR consumed it → runtime backflow current"
• "⚠️ Change in VMR → but runtime backflow is 3 builds behind"
• "❌ PR hasn't merged yet — not in pipeline"

SDK Version Trace

Run the script to trace from an SDK version string to a component commit SHA:

# Trace runtime SHA in a specific SDK version
./scripts/Get-SdkVersionTrace.ps1 -SdkVersion "10.0.300-preview.26117.103"

# Trace a specific component
./scripts/Get-SdkVersionTrace.ps1 -SdkVersion "10.0.300-preview.26117.103" -Component "aspnetcore"

# Check if specific commits are included
./scripts/Get-SdkVersionTrace.ps1 -SdkVersion "10.0.300-preview.26117.103" -CheckCommit "b226ba1f77a4","f3bc0212e637"

# Just decode the version string
./scripts/Get-SdkVersionTrace.ps1 -SdkVersion "10.0.300-preview.26117.103" -DecodeOnly

The script decodes the SDK version, maps to a VMR branch, finds the build in AzDO, and walks the dependency chain through source-manifest.json (and Version.Details.xml for servicing branches that don't source-build all components).

⚠️ SDK version dates use Arcade's SHORT_DATE formula: YY*1000 + MM*50 + DD (NOT YYDDD day-of-year). 26117 = Feb 17, 2026, NOT April 27. See references/sdk-version-format.md.

⚠️ Servicing branches (2xx, 3xx) do NOT source-build runtime. The script automatically follows the dependency chain through Version.Details.xml to the 1xx branch. See references/servicing-topology.md.

References

• Internal VMR branches: See references/internal-vmr.md
• SDK version format: See references/sdk-version-format.md
• Servicing branch topology: See references/servicing-topology.md
• AzDO pipeline IDs and queries: See references/azdo-pipelines.md