Pub Package Explorer

Use this workflow to read package source code for Dart or Flutter, including packages not currently installed in the project.

Choose the Source Strategy

1. Prefer .dart_tool/package_config.json when the package is already in the project dependency graph.
2. Use dart pub unpack when the package is missing from package_config.json or when source needs inspection before adding the dependency.
3. Prefer the installed package path when both are available to match the project-resolved version.

Resolve a Package Source Path

1. Confirm the project contains .dart_tool/package_config.json.
2. Read the package entry from packages[] by name.
3. Extract:

• rootUri (package root, usually in pub cache)
• packageUri (usually lib/)

4. Build source path as rootUri + packageUri.
5. Convert file:// URI to a filesystem path before reading files.

Use this command pattern:

PACKAGE="analyzer"
CONFIG=".dart_tool/package_config.json"

SOURCE_URI="$(jq -r --arg pkg "$PACKAGE" '
  .packages[]
  | select(.name == $pkg)
  | (.rootUri + (if (.rootUri | endswith("/")) then "" else "/" end) + .packageUri)
' "$CONFIG")"

Convert the URI to a local path:

SOURCE_PATH="$(printf '%s\n' "$SOURCE_URI" | sed 's#^file://##')"

Then inspect source files under that directory (rg, ls, cat).

Unpack a Package That Is Not Installed

Use this path when the package is not in .dart_tool/package_config.json or when pre-install inspection is needed.

PACKAGE="analyzer"              # or "analyzer:7.4.0"
OUTPUT_DIR="/tmp/pub-unpack"

mkdir -p "$OUTPUT_DIR"
dart pub unpack "$PACKAGE" --output "$OUTPUT_DIR"

Find the extracted directory and inspect it:

PACKAGE_NAME="${PACKAGE%%:*}"
UNPACKED_DIR="$(find "$OUTPUT_DIR" -maxdepth 1 -type d -name "${PACKAGE_NAME}-*" | sort | tail -n 1)"

ls "$UNPACKED_DIR"
ls "$UNPACKED_DIR/lib"
rg --files "$UNPACKED_DIR/lib"

Notes:

• dart pub unpack downloads and extracts a package even when it is not in the current project's dependencies.
• Use --force if the output directory already contains an unpacked copy that must be overwritten.
• --output controls where the extracted <package>-<version> folder is created.

Useful Variants

• Return only the package root:

jq -r --arg pkg "$PACKAGE" '
  .packages[]
  | select(.name == $pkg)
  | .rootUri
' .dart_tool/package_config.json

• Return both root and package URI:

jq -r --arg pkg "$PACKAGE" '
  .packages[]
  | select(.name == $pkg)
  | "\(.rootUri)\t\(.packageUri)"
' .dart_tool/package_config.json

Verification and Error Handling

• If no package matches in package_config.json, switch to dart pub unpack instead of stopping.
• If .dart_tool/package_config.json is missing, run dependency resolution first (dart pub get or flutter pub get) and retry.
• Prefer reading from rootUri + packageUri because package APIs are exposed from that subpath, not always from the package root.
• If dart pub unpack fails, report the exact failure (for example network access, invalid descriptor, or permissions for output path).