dimpact

dimpact is a CLI for language-aware impact analysis from git diffs or explicit symbol seeds. It maps changed lines to symbols, builds reference relationships, and reports what code is likely affected.

What it does

• Parse unified git diffs from stdin
• Detect changed symbols in Rust, Ruby, Python, JavaScript, TypeScript, TSX, Go, and Java
• Compute caller / callee impact from a diff or from seed symbols
• Output JSON, YAML, DOT, or HTML
• Generate Symbol IDs from file / line / name
• Persist analysis data with a local SQLite cache
• Use Tree-Sitter by default, with an LSP engine available when needed

Installation

Build from source

cargo build --release
./target/release/dimpact --help

Install from crates.io with cargo

cargo install dimpact
dimpact --help

Install with Docker

docker pull ghcr.io/n01e0/dimpact:latest
docker run --rm ghcr.io/n01e0/dimpact:latest --help

If you want to analyze the current repository from the container, mount the working tree at /work and pipe the diff on stdin:

git diff --no-ext-diff | docker run -i --rm -v "$PWD":/work ghcr.io/n01e0/dimpact:latest impact --direction callers --with-edges -f json

Basic usage

1. Parse a diff

git diff --no-ext-diff | dimpact diff -f json

2. Show changed symbols

git diff --no-ext-diff | dimpact changed --lang auto -f json

3. Compute impact from a diff

git diff --no-ext-diff | dimpact impact --direction callers --with-edges -f json

4. Compute impact from explicit seeds

dimpact impact \
  --seed-symbol 'rust:src/lib.rs:fn:foo:12' \
  --direction callers \
  -f json

5. Generate Symbol IDs

dimpact id --path src/lib.rs --name foo --kind fn --raw

6. Inspect registered JSON schemas

dimpact schema --list
dimpact schema --id dimpact:json/v1/impact/default/summary_only/call_graph
dimpact schema resolve impact --per-seed --with-edges --with-propagation

JSON schema surface

The schema subcommand family is an inspection/help layer for JSON contracts. It does not rewrite the normal JSON payload shape.

That means:

• dimpact diff -f json still returns its top-level array payload
• dimpact changed -f json still returns its top-level object payload
• dimpact impact -f json still returns its top-level object payload
• dimpact impact --per-seed -f json still returns its top-level array payload
• dimpact id -f json still returns its top-level array payload

Normal JSON output does not embed _schema, json_schema, or data wrapper fields.

Use these commands to work with the schema layer directly:

• dimpact schema --list — list the registered canonical schema ids and document paths
• dimpact schema --id <schema-id> — fetch the concrete JSON Schema document for one id
• dimpact schema resolve <subcommand> ... — resolve the canonical profile/id/path that a JSON command corresponds to

Schema documents live under resources/schemas/json/v1/.

Main commands

Command	Purpose
diff	Parse unified diff input from stdin
changed	Resolve changed lines to symbols
impact	Compute callers / callees / both from diff or seeds
id	Generate Symbol IDs from file, line, and name
schema	List, resolve, and fetch registered JSON schemas
cache	Build, update, inspect, or clear the local cache
completions	Generate shell completion scripts

Useful options

• --direction callers|callees|both
• --with-edges
• --max-depth N
• --engine auto|ts|lsp
• --seed-symbol LANG:PATH:KIND:NAME:LINE
• --seed-json <json|path|->
• -f json|yaml|dot|html

Cache

dimpact can persist symbols and reference edges in SQLite for faster repeated analysis.

dimpact cache build --scope local
dimpact cache stats --scope local

Default local cache path:

.dimpact/cache/v1/index.db

Notes

• diff, changed, and diff-based impact expect unified diff input on stdin.
• Seed-based impact does not require stdin.
• Tree-Sitter is the default engine.
• LSP mode is available via --engine lsp.

Advanced docs

For LSP graduation notes, strict-LSP workflow details, and design memos, see docs/.

License

MIT. See LICENSE.