Exploring assets, asset manifests and how they are scoped

This repository provides a sandbox for exploring asset behavior across package library imports. Packages have hierarchical and transitive relationships across the example application and library tests.

packages, libraries and assets scoped to our program
packages, libraries and assets scoped to our tests

flowchart LR

subgraph demo
    lib-demo[lib]
    subgraph assets-demo[assets]
    end
    subgraph pubspec-test[pubspec]
        depend-demo[dependencies]
        depend-test-demo[dev<br/>dependencies]
    end

end

depend-demo -.-> utilities
depend-test-demo -.-> test_tools

subgraph test_tools
    lib-test[lib]
    subgraph assets-test[assets]
        direction TB
        assets-tools-docs[docs]
        assets-tools-models[models]
    end
    subgraph pubspec-tools[pubspec]
        direction TB
        depend-tools[dependencies]
        depend-tools-test[dev<br/>dependencies]
    end
end

subgraph utilities
    lib-utilities[lib]
    subgraph assets-utilities[assets]
        direction TB
        assets-utilities-docs[docs]
        assets-utilities-models[models]
    end
    subgraph pubspec-utilities[pubspec]
        direction TB
        depend-utilities[dependencies]
        depend-test-utilities[dev<br/>dependencies]
    end
end

Youtube videos

Flutter Assets Demo Project structure

This project contains several cross package references.

The [demo] package contains references to test_utils, theme_common and utilities which all have their own assets. test_utils is only referenced as a dev dependency and is only in scope in tests. theme_common, utilities and test_tools have their own assets that become available to any program or package that takes them as a dependency pulling them into scope.

Assets in test_tools are only available to the demo tests because they are only part of dev_dependencies.
The assets in theme_common and utilities area available to both tests and the program because they are brought in via dependencies in the pubspec.yaml.

pubspec.yaml

Dependencies in this repository

flowchart LR

subgraph demo-example[demo example app]
    lib-example[lib]
    subgraph assets-example[assets]
    end
    subgraph pubspec-demo[pubspec]
        depend-example[dependencies]
        depend-test-example[dev<br/>dependencies]
    end
end

subgraph demo
    lib-demo[lib]
    subgraph assets-demo[assets]
    end
    subgraph pubspec-test[pubspec]
        depend-demo[dependencies]
        depend-test-demo[dev<br/>dependencies]
    end

end

depend-example -.-> demo
depend-demo -.-> theme_common
depend-demo -.-> utilities
depend-test-demo -.-> test_tools

subgraph test_tools
    lib-test[lib]
    subgraph assets-test[assets]
        direction TB
        assets-tools-docs[docs]
        assets-tools-models[models]
    end
    subgraph pubspec-tools[pubspec]
        direction TB
        depend-tools[dependencies]
        depend-tools-test[dev<br/>dependencies]
    end
end

subgraph theme_common
    lib-theme[lib]
    subgraph assets-theme[assets]
        direction TB
        assets-theme-docs[docs]
        assets-theme-diagrams[diagrams]
    end
    subgraph pubspec-theme[pubspec]
        direction TB
        depend-theme[dependencies]
        depend-test-theme[dev<br/>dependencies]
    end
end

subgraph utilities
    lib-utilities[lib]
    subgraph assets-utilities[assets]
        direction TB
        assets-utilities-docs[docs]
        assets-utilities-models[models]
    end
    subgraph pubspec-utilities[pubspec]
        direction TB
        depend-utilities[dependencies]
        depend-test-utilities[dev<br/>dependencies]
    end
end

Assets visible to applications and libraries

Applications and packages see everything refenrenced in dependencies: in pubspec.yaml

dependencies:
  flutter:
    sdk: flutter
  utilities:
    path: ../utilities
  theme_common:
    path: ../theme_common

The demo application sees assets transitively brought in from library packages packages but does not see the tools_assets.

[
    "packages/cupertino_icons/assets/CupertinoIcons.ttf",

    "packages/theme_common/assets/diagrams/draw201.vsdx",
    "packages/theme_common/assets/docs/doc201.md",
    "packages/theme_common/assets/docs/doc202.md",

    "packages/utilities/assets/docs/doc101.md",
    "packages/utilities/assets/docs/doc102.md",
    "packages/utilities/assets/models/model101.json",

    "packages/utilities/lib/resources/icon101.png",
    "packages/utilities/lib/resources/libassets.json"
]

Files in lib will be packaged up with the app but they only appear to the AssetManager if you add them to the assets in pubspec.yaml. You must add them to the asset list if you want them to be picked up by AssetManager or show up in the AssetManifest.

Assets visible to tests

Tests see everythining in pubspec.yaml that is scoped to dependencies or to dev_dependencies. Tests can use the test_tools assets that are scoped to the tests in pubspec.yaml

dependencies:
  flutter:
    sdk: flutter
  utilities:
    path: ../utilities
  theme_common:
    path: ../theme_common

dev_dependencies:
  flutter_test:
    sdk: flutter
  flutter_lints: ^2.0.0
  test_tools:
    path: ../test_tools

We can see this when interrogating for available assets.

[
    "packages/test_tools/assets/docs/sample301.md",
    "packages/test_tools/assets/models/meta301.json",
    "packages/test_tools/assets/models/template301.json",

    "packages/theme_common/assets/diagrams/draw201.vsdx",
    "packages/theme_common/assets/docs/doc201.md",
    "packages/theme_common/assets/docs/doc202.md",

    "packages/utilities/assets/docs/doc101.md",
    "packages/utilities/assets/docs/doc102.md",
    "packages/utilities/assets/models/model101.json",

    "packages/utilities/lib/resources/icon101.png",
    "packages/utilities/lib/resources/libassets.json"
]

Non code files in /lib

Flutter Asset behavior in hot reload

Assets that are added via pubspec.yaml are copied into a location that is used to populate the assets. That location may not be cleared when referencing the package via relative location from the demo pubspect.yaml. This means that assets removed from the included pubspec.yaml may still appear in the AssetManifest until some type of clean operation occurs.

freemansoft/flutter_assets_demo