Normalize internal component documentation

docs/internal/publish.md

@@ -1,52 +1,63 @@
-# Publish
+# Publish Internals
+
+Audience: developers and LLM coding agents changing `internal/publish`.
 
 ## Purpose
 
-`internal/publish` plans and executes publication for one validated source bundle and one destination.
+`internal/publish` plans and executes publication for one validated source bundle and one destination bundle path. It owns destination comparison mapping, output selection, URL planning, managed cleanup selection, replacement safety, and destination state projection.
 
-## Inputs and outputs
+## Inputs And Outputs
 
-Inputs are a source bundle, source backend, destination backend, pipeline id, destination id, publish policy, transform policy, optional link policy, transformer resolver, transfer policy, path mapping mode, destination bundle path, existing destination state, and whether explicit force was requested for the current run.
+Inputs are a source bundle, source backend, destination backend, pipeline id, destination id, destination bundle path, path mapping mode, publish policy, transform policy, optional link policy, transformer resolver, transfer policy, distributor version, and force flag.
 
-Output is a plan with an action, reason, optional primary URL, and selected source or generated outputs. Execution writes selected source files, generated files, and `.distributor.json` for publish or replacement actions.
-
-## Actions
-
-Supported actions are `publish_new`, `replace_older`, `force_replace`, `skip_same`, `skip_destination_newer`, `fail_conflict`, and `fail_unmanaged`.
-
-## Failure behavior
-
-Planning fails when request fields are incomplete, publish and transform policies are invalid, selected outputs collide, HTML output is requested without Markdown inputs, destination state is invalid, destination content is unmanaged without force, or transfer policy maps the comparison outcome to failure.
-
-Execution fails if a write, delete, state serialization, or context check fails. Outputs written during a failed publish attempt are cleaned up through managed deletion where possible.
+Output from planning is a `Plan` with action, reason, destination identity, selected outputs, optional existing state, optional primary URL, and force metadata. Execution writes selected source outputs, generated outputs, and `.distributor.json` for executable publish or replacement actions.
 
 ## Boundaries
 
-The package publishes source files and Markdown-to-HTML outputs. Markdown sidecar mode writes same-directory `.html` outputs, and Markdown index mode writes `index.html`. Backend behavior is supplied through `internal/storage`; app runtime supplies local, SSH, and S3 backends.
+The package does not parse CLI flags, load config files, open concrete adapters, discover source bundles, select fixed-path bundle candidates, register transforms, or render command output. The app layer supplies validated request data and concrete dependencies.
 
-The package uses `internal/state` for destination comparison, `internal/storage` for IO, and the shared `internal/config` publish/transform policy helper for request validation. It resolves transforms through a narrow resolver supplied by the caller; concrete transform registration is owned by the app layer. It does not parse CLI flags, load config files, or choose which source bundles a destination receives.
+External destination state semantics are documented in `docs/integrations/destination-state.md`.
 
-The package owns projection from planned publish outputs to destination state output records and managed destination output paths. App JSON results and notification events keep their own schemas, but may use the publish output projection to avoid field-mapping drift.
+## Config Fields Used
 
-The app layer computes the destination bundle path before planning. `preserve_relative` destinations pass the source-root-relative bundle path. `fixed` destinations pass an empty destination bundle path, which means the destination backend root, and pass only the newest selected source bundle for that destination.
+The package consumes already-defaulted config values for destination `publish`, `transform`, `links`, `transfer`, and path mapping mode. It uses `config.ValidatePublishTransformPolicy` for publish/transform consistency.
 
-When link config is present, publish planning builds per-output URLs from `links.base_url`, the destination bundle path, and each output path. `index.html` outputs use directory-style URLs. The primary URL is selected from planned outputs according to the destination primary policy.
+## Adapters Used
 
-## Safety
+The package depends on `internal/storage.Backend` for source and destination IO, and on a narrow transformer resolver interface for generated outputs. It does not import concrete storage adapters or concrete transform implementations.
 
-Normal replacement deletes only outputs recorded in existing destination state plus `.distributor.json`. Forced replacement deletes the bounded destination bundle path before writing outputs and state. Failed writes trigger cleanup of outputs written during the failed attempt where practical.
+## State And Manifest Behavior
 
-## Tests
+Planning inspects destination state through `internal/state`, compares it with the source manifest, and maps comparison outcomes plus transfer policy into actions: `publish_new`, `replace_older`, `force_replace`, `skip_same`, `skip_destination_newer`, `fail_conflict`, or `fail_unmanaged`.
 
-Before changing publish behavior, inspect tests under `internal/publish` and run tests under `internal/app`.
+Execution writes destination state after selected outputs are written. Destination state includes copied source output metadata, generated output metadata, embedded source manifest, link metadata when configured, pipeline id, destination id, and publication timestamp.
 
-## Invariants
+## Skip And Resume Behavior
 
-- Publish planning is deterministic for the same source, destination state, policies, and transform outputs.
-- Destination bundle paths are caller-supplied and are interpreted relative to the destination backend root.
-- URL generation uses URL path semantics and does not infer public URLs from backend configuration.
+`skip_same` and `skip_destination_newer` execute as no-ops. Normal replacement removes only managed output paths from existing state plus `.distributor.json`; this allows retries without broad deletion. Failed writes trigger cleanup of outputs written during that failed attempt where practical.
+
+Forced replacement is explicit per request and deletes the bounded destination bundle path before writing new outputs and state.
+
+## Failure Behavior
+
+Planning fails for incomplete requests, invalid publish/transform policy, output path collisions, invalid destination state, unmanaged destination content without force, conflict outcomes not allowed by transfer policy, unresolved transforms, invalid Markdown output selection, and invalid link URL planning.
+
+Execution fails on delete, read, transform output, write, state validation, state serialization, or context errors. Execution refuses actions that are not executable publish or replacement actions.
+
+## Tests To Inspect
+
+- `internal/publish/*_test.go`
+- `internal/app/run_test.go`
+- `internal/state/*_test.go`
+- `internal/transform/markdown/*_test.go`
+
+## Architectural Invariants
+
+- Planning is deterministic for the same request and destination state.
+- Destination bundle paths are caller-supplied and backend-root-relative.
+- URL generation uses URL path semantics and never infers public URLs from backend config.
 - Normal replacement deletes only managed paths recorded in existing state plus `.distributor.json`.
-- Forced replacement is explicit per run and deletes only within the destination bundle path.
-- Publish execution writes destination state after selected outputs are written.
-- Transform implementations are resolved through an interface supplied by the caller.
-- Unmanaged destination content is overwritten only by explicit forced replacement.
+- Forced replacement deletes only within the supplied destination bundle path.
+- Destination state is written after selected outputs are written.
+- Transform resolution stays behind a caller-supplied interface.
+- Unmanaged content is claimed only by explicit force.