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Impact Gate Impact Gate Impact Gate

Knowledge Graph Integration

Function-level accuracy

Generate a code knowledge graph to upgrade impact-gate from file-level to function-level analysis. Trace changed functions to their callers, identify which specific functions lack test coverage, and get precise impact reports.

Why Use a Knowledge Graph

Without a knowledge graph, impact-gate works at file level: “post.go changed” maps to the “post” family. With a knowledge graph, it works at function level:

SetChannelManagedCategory (channel_category.go:288)
  → called by: patchChannel (channel.go:455)
  → tested by: managed_categories.spec.ts


ClearChannelManagedCategory (channel_category.go:319)
  → called by: patchChannel (channel.go:468)
  → tested by: (none)  ← coverage gap!

This eliminates false positives (claiming a flow is untested when the test covers a different function in the same file) and false negatives (missing a coverage gap because a test file exists but doesn’t exercise the changed function).

Supported Tools

impact-gate auto-detects knowledge graphs from two tools:

Graphify uses tree-sitter for deterministic AST extraction across 20 languages. No LLM required for the code analysis pass.

Terminal window
pip install graphifyy
cd your-repo
graphify .

Output: .graphify/graph.json — auto-detected by impact-gate.

Languages: TypeScript, JavaScript, Go, Python, Rust, Java, C, C++, Ruby, C#, Kotlin, Scala, PHP, Swift, and more.

Understand-Anything (for Claude Code users)

Understand-Anything generates a knowledge graph using AI agents. Requires a Claude Code or similar AI runtime.

Output: .understand-anything/knowledge-graph.json — auto-detected by impact-gate.

Using KG with impact-gate

Once you have a knowledge graph, impact-gate automatically uses it:

Terminal window
# Generate the KG (one-time, or after major refactors)
graphify .


# Run review — KG auto-detected, function-level output enabled
impact-gate review --path . --since origin/main

The review output will include:

Untested Functions (need coverage):
  ❌ ClearChannelManagedCategory (channel_category.go) -- called by: patchChannel
  ❌ handleManagedCategoryWebSocket (websocket_actions.ts)


Tested Functions:
  ✅ SetChannelManagedCategory -- tested by: managed_categories.spec.ts
  ✅ patchChannel -- tested by: channel_test.go

Accuracy Levels

LevelWhatHow
File-level (~65%)“post.go changed → post family”init --scan (default, zero cost)
KG-level (~80%)“patchChannel changed → traces callers → finds untested paths”graphify . then review
Runtime-level (~90%)“this test run covered lines 430-470 but not 455-472”traceability-capture with coverage data

How It Works

  1. KG Loading: impact-gate checks for .graphify/graph.json or .understand-anything/knowledge-graph.json
  2. Node Matching: Changed files are matched to KG nodes (functions, classes, components)
  3. Call Chain Traversal: BFS walks up the call graph to find all callers (up to depth 3)
  4. Test Coverage Mapping: For each affected function, finds test nodes connected via tests edges
  5. Gap Detection: Functions with no test coverage are flagged in the review output

Regenerating the KG

Regenerate after:

  • Major refactors that change function signatures or call chains
  • Adding new modules or entry points
  • Before a release review
Terminal window
# Graphify caches by SHA — only reprocesses changed files
graphify .