[dannote]

Only one manifest was read per node: the host application's in development, or the first loaded application shipping one in a release. A library that uses icons in its own components could not ship them. The host's compiler scans only the host's sources, and the library's own manifest was never read.

I hit this adding icons to PhoenixReplay's dashboard, which renders inside host applications.

Change

• Runtime icons come from every loaded application's manifest. get_icons/0 and reload/0 merge the manifests of loaded applications, sorted by name, with the application's own manifest last so it wins on conflicts. A library now ships priv/iconify/manifest.json, and hosts need no configuration.
• Applications without a code path are skipped, rather than resolving priv/ against the working directory.
• The compiler and the mix phoenix_iconify.* tasks are unchanged: they read and write only the current project's own manifest.
• add_icon/3 with persist: true writes the application's own manifest plus the new icon. It used to write the merged runtime set, which would copy a library's icons into the host's manifest.
• Manifest.read_all/1 and Manifest.manifest_paths/0 expose the merged view.
• README: an "Icons in libraries" section on committing the manifest and listing it in the package files. CHANGELOG: Unreleased entries.

Tests

library_manifests_test.exs loads fixture applications with their own priv/iconify/manifest.json on the code path. It covers merge precedence, a library's icons rendering with the host winning on a clash, and add_icon/3 persisting only the own icons. Making get_icons/0 read only the own manifest, or persisting the merged set, each fails a test. mix ci passes.