DDeps

Source review support tool

A tool to create a module dependency graph for the D language. The feature is that you can record snapshots in two versions and compare them to visualize the differences.

Screenshot (Example)

basic

no core, no std

exclude rx.subject

Requirements

1. dub
2. Graphviz (for DOT/SVG output)
3. Mermaid-capable viewer/editor (only when using --format=mermaid)

Settings

For library (example)

	"configurations": [
		{
			"name": "default"
		},
		{
			"name": "diff",
			"postGenerateCommands": [
				"dub build -c makedeps",
				"dub fetch ddeps",
				"dub run ddeps -- --focus=rx -o deps.dot",
				"dot -Tsvg -odeps.svg deps.dot"
			]
		},
		{
			"name": "diff-update",
			"postGenerateCommands": [
				"dub fetch ddeps",
				"dub run ddeps -- --update"
			]
		},
		{
			"name": "makedeps",
			"dflags": ["-deps=deps.txt"]
		}
  ]

For executable

	"configurations": [
		{
			"name": "default"
		},
		{
			"name": "diff",
			"postGenerateCommands": [
				"dub build -c makedeps",
				"dub fetch ddeps",
				"dub run ddeps -- -o deps.dot",
				"dot -Tsvg -odeps.svg deps.dot"
			]
		},
		{
			"name": "diff-update",
			"postGenerateCommands": [
				"dub fetch ddeps",
				"dub run ddeps -- --update"
			]
		},
		{
			"name": "makedeps",
			"dflags": ["-deps=deps.txt"]
		}
  ]

For Mermaid output (example)

Use the same configurations but swap the post command to emit Mermaid instead of DOT/SVG:

{
	"name": "diff-mermaid",
	"postGenerateCommands": [
		"dub build -c makedeps",
		"dub fetch ddeps",
		"dub run ddeps -- --format=mermaid --output=deps.mmd"
	]
}

Usage

At first

create lock file

dub build -c makedeps
dub build -c diff-update

Basic

1. Modify source
2. Update diff
   • dub build -c diff
3. Do review with the dependency graph diff
   • Open the deps.svg in browser, or generate Mermaid with dub run ddeps -- --format=mermaid --output=deps.mmd and view it in a Mermaid-enabled editor.

Compare 2 versions

1. checkout a target version
   • git reset --hard XXX or git checkout XXXXX
2. reset to source version
   • git reset --hard HEAD~10 (e.g. 10 versions ago)
3. create deps-lock.txt
   • dub build -c makedeps
   • dub build -c diff-update
   • if dub.json / dub.sdl has not configure then add these.
4. reset to target version
   • git reset --hard ORIG_HEAD
5. make diff
   • dub build -c diff
6. open deps.svg (or produce Mermaid: dub run ddeps -- --format=mermaid --output=deps.mmd)

Arguments

name	Usage	description	default
input	-i XXX or --input=XXX	deps file name	deps.txt
output	-o XXX or --output=XXX	destination file name	write to stdout
update	-u or --update	update lock file	false
lock	-l XXX or --lock=XXX	lock file name	deps-lock.txt
focus	-f XXX or --focus=XXX	filtering target by name	app
depth	-d N or --depth=N	search depth	1
exclude	-e XXX [-e YYY] or --exclude=XXX [--exclude=YYY]	exclude module names	object
format	`--format=dot	mermaid`	output format
allow-rule	--allow-rule=A->B where A/B are module names or group:name	allow-list per source; other targets from that source warn
group	-g NAME=mod1,mod2 or -g mod	group nodes; short form includes submodules; multiple -g allowed
help	--help	show help

Mermaid output

You can render the diff as a Mermaid graph (useful in Markdown viewers that support Mermaid):

dub run ddeps -- --format=mermaid --output=deps.mmd

Open deps.mmd in a Mermaid-capable viewer/editor to inspect the graph. Added nodes/edges are green, removed are red, kept are neutral. Graphviz is not required for Mermaid output.

Grouping example

dub run ddeps -- --group util --group UI=app.ui,app.ui.widgets --format=dot -o deps.dot

--group util creates a group for util and its submodules (e.g., util.log). --group UI=... groups the exact modules listed. Groups are rendered as clusters in DOT and subgraphs in Mermaid.

Wildcard helper: suffix .* inside --group targets the module and all submodules even in long form, e.g. --group external=mir.*,numir or short form --group mir.*.

Integration / sample outputs script

Run once to clone sample repos and emit DOT/Mermaid (and SVG if dot exists):

rdmd ./scripts/sample_outputs.d

Artifacts live under ./tmp/test-<repo>/ and include grouping/exclude variants. For md, both with/without -e core -e std are generated.

Rx diff example is built in: the script checks out rx tag v0.7.0 as the old reference, compares against current HEAD, and writes grouped color-diff graphs (deps-diff-full.dot/.mmd/.svg) showing red/green changes.

Dependency direction warnings

Use --allow-rule to allow specific downward directions between layers (e.g., --allow-rule=group:ui->group:app, --allow-rule=group:app->group:infra). For any source that has allow-rules, edges to non-allowed targets are warned: rendered bold/dashed (kept edges also red) with a warning message on stdout. Sources without rules are ignored. This helps enforce layered architectures where modules only depend in approved directions.