boundaries.toml

# boundaries.toml — semantic module dependency policy (v2)
#
# Enforces the architecture rules from docs/architecture/dependency-rules.md
# through the repo-owned `cargo xtask architecture` checker.
#
# Run:   cargo xtask architecture check
# CI:    cargo run --locked --package xtask -- architecture check
#
# Boundaries listed below are evaluated as source boundaries. Omitting a
# top-level module (e.g. internal_tests) keeps it out of the governed set.

version = 1

# internal_tests is intentionally omitted. It remains a cross-pipeline bucket
# for owner-spanning regressions rather than a governed architecture boundary.

[modules]
errors = {}
format = {}
timeline = {}
simplification = {}
graph = {}
mermaid = {}
engines = { tags = { role = "runtime-facade" } }
render = { tags = { role = "runtime-facade" } }
payload = {}
registry = {}
diagrams = {}
builtins = { tags = { role = "runtime-facade" } }
commands = {}
mmds = {}
views = {}
frontends = { tags = { role = "runtime-facade" } }
runtime = {}

# --- Allow rules (one per governed source boundary) ---

[[rules]]
id = "allow-errors"
type = "allow"
[rules.config]
source = "errors"
allowed = []

[[rules]]
id = "allow-format"
type = "allow"
[rules.config]
source = "format"
allowed = ["errors"]

[[rules]]
id = "allow-timeline"
type = "allow"
[rules.config]
source = "timeline"
allowed = []

[[rules]]
id = "allow-simplification"
type = "allow"
[rules.config]
source = "simplification"
allowed = ["errors", "format"]

# Must not import render, engines, diagrams, or runtime.
[[rules]]
id = "allow-graph"
type = "allow"
[rules.config]
source = "graph"
allowed = ["errors", "format"]

# Plan 0146: graph::edge_marker is a leaf submodule — pure data keyed on Arrow,
# consumed by graph::routing's label clamp and by internal_tests' boundary
# assertion. Enumerate allowed inbound deps explicitly so the helper cannot
# silently grow couplings to other graph submodules.
[[rules]]
id = "edge-marker-leaf-allow"
type = "allow"
[rules.config]
source = "graph::edge_marker"
allowed = ["graph::edge"]

[[rules]]
id = "allow-mermaid"
type = "allow"
[rules.config]
source = "mermaid"
allowed = ["errors", "graph", "timeline"]

# Must not import render, diagrams, or runtime.
[[rules]]
id = "allow-engines"
type = "allow"
[rules.config]
source = "engines"
allowed = ["errors", "format", "graph"]

# Must not import diagrams, config, engines, or runtime.
[[rules]]
id = "allow-render"
type = "allow"
[rules.config]
source = "render"
allowed = ["format", "graph", "simplification", "timeline"]

# Shared text/SVG helpers sit below the family-specific renderers.
[[rules]]
id = "render-submodule-layers"
type = "layers"
[rules.config]
order = ["render::text", "render::svg", "render::graph", "render::timeline"]

# Shared render utility layers should not depend on each other directly.
[[rules]]
id = "render-shared-submodules-independent"
type = "independence"
[rules.config]
members = ["render::text", "render::svg"]

[[rules]]
id = "allow-payload"
type = "allow"
[rules.config]
source = "payload"
allowed = ["graph", "timeline"]

[[rules]]
id = "allow-registry"
type = "allow"
[rules.config]
source = "registry"
allowed = ["errors", "format", "payload"]

# Must not import render or engines (stops at into_payload).
[[rules]]
id = "allow-diagrams"
type = "allow"
[rules.config]
source = "diagrams"
allowed = ["errors", "graph", "mermaid", "payload", "registry", "timeline"]

[[rules]]
id = "allow-builtins"
type = "allow"
[rules.config]
source = "builtins"
allowed = ["diagrams", "format", "registry"]

[[rules]]
id = "allow-commands"
type = "allow"
[rules.config]
source = "commands"
allowed = ["errors", "format", "graph", "mmds", "runtime"]

# Must not import diagrams, config, engines, render, or runtime.
[[rules]]
id = "allow-mmds"
type = "allow"
[rules.config]
source = "mmds"
allowed = ["errors", "format", "graph", "simplification", "timeline"]

[[rules]]
id = "allow-views"
type = "allow"
[rules.config]
source = "views"
allowed = ["graph", "mmds"]

[[rules]]
id = "allow-frontends"
type = "allow"
[rules.config]
source = "frontends"
allowed = ["mermaid", "mmds"]

[[rules]]
id = "allow-runtime"
type = "allow"
[rules.config]
source = "runtime"
allowed = [
    "builtins", "engines", "errors",
    "format", "frontends", "graph", "mermaid", "mmds",
    "payload", "registry", "render", "simplification", "timeline", "views",
]

# --- Layers rule (pipeline spine ordering) ---
# Lower layers must not depend on higher layers.

[[rules]]
id = "pipeline-layers"
type = "layers"
[rules.config]
order = ["errors", "format", "graph", "engines", "render", "runtime"]

# --- Independence rules (peer isolation) ---
# These frontends must not depend on each other.

[[rules]]
id = "parser-independence"
type = "independence"
[rules.config]
members = ["mermaid", "mmds"]

# The three pipeline pillars must not cross-depend.
[[rules]]
id = "pipeline-pillar-independence"
type = "independence"
[rules.config]
members = ["engines", "render", "diagrams"]

# --- Protected rules (facade-only access) ---
# Boundaries tagged role=runtime-facade are only accessible through runtime.

[[rules]]
id = "protect-runtime-facades"
type = "protected"
[rules.config]
targets = { tag = "role", value = "runtime-facade" }
allowed_importers = ["runtime"]

# diagrams is accessed only by builtins (which wires it into the registry).
[[rules]]
id = "protect-diagrams"
type = "protected"
[rules.config]
targets = ["diagrams"]
allowed_importers = ["builtins"]

# --- Acyclic rule (DAG guarantee) ---
# The full boundary graph must be cycle-free.
# The "*" wildcard expands to every discovered module at all depths.
# Parent/child edges (mod.rs ↔ child) are skipped — these are a normal
# Rust structural pattern. Any non-structural cycle must be documented
# as an explicit exception below.

[[rules]]
id = "no-boundary-cycles"
type = "acyclic"
[rules.config]
members = ["*"]
skip_parent_child = true