Canton Network Open-Source Repositories

This skill provides comprehensive knowledge about the Canton Network open-source ecosystem, repository relationships, and build processes.

Activation

Use this skill when:

• Working with Canton Network, DAML, or Splice repositories
• Investigating version compatibility issues
• Understanding enterprise vs community differences
• Debugging LF version or package ID mismatches
• Building Canton participants or Splice applications

Repository Hierarchy

┌─────────────────────────────────────────────────────────────────┐
│                    Splice Version (e.g., 0.5.4)                 │
│         github.com/digital-asset/decentralized-canton-sync     │
│   Applications: Validator, SV, Wallet, Scan, Amulet (CC)       │
└─────────────────────────┬───────────────────────────────────────┘
                          │ depends on
                          ▼
┌─────────────────────────────────────────────────────────────────┐
│                   Canton Version (e.g., 3.4.9)                  │
│               github.com/digital-asset/canton                   │
│     Runtime: Participant, Sequencer, Mediator, Admin API       │
└─────────────────────────┬───────────────────────────────────────┘
                          │ depends on
                          ▼
┌─────────────────────────────────────────────────────────────────┐
│                    DAML SDK (e.g., 3.4.9)                       │
│                github.com/digital-asset/daml                    │
│    Compiler: damlc, LF Engine, Ledger API, stdlib, protobuf    │
└─────────────────────────────────────────────────────────────────┘

Repository Details

1. DAML SDK (github.com/digital-asset/daml)

Purpose: Smart contract language, compiler, and runtime libraries.

Key Directories:

daml/
├── sdk/
│   ├── compiler/damlc/          # Haskell compiler source
│   │   └── lib/DA/Cli/Options.hs  # --target version validation
│   ├── daml-lf/
│   │   ├── language/            # LF version definitions (Scala)
│   │   ├── engine/              # LF execution engine
│   │   └── archive/             # DALF protobuf format
│   └── canton/                  # Canton runtime (submodule)
├── ledger-api/                  # gRPC API definitions
└── VERSION                      # SDK version string

LF Version Definitions (LanguageVersion.scala at v3.4.9):

// V2 versions defined
val List(v2_1, v2_2, v2_dev) = AllV2  // Line 51 - v2_2 IS defined

// Version ranges
case Major.V2 => VersionRange(v2_1, v2_2)  // Line 171 - StableVersions includes v2_2
def AllVersions = VersionRange(v2_1, v2_dev)

// Features at v2_2:
val flatArchive = v2_2
val kindInterning = flatArchive
val exprInterning = flatArchive
val explicitPkgImports = v2_2
val unsafeFromInterfaceRemoved = v2_2

Note: v2_2 IS in SDK v3.4.9 source. Older snapshots may not include it.

damlc Target Validation (Options.hs):

lfVersionOpt :: Parser LF.Version
-- Validates against LF.supportedOutputVersions
-- Error: "Unknown Daml-LF version: X" if not in list

2. Canton (github.com/digital-asset/canton)

Purpose: Distributed ledger runtime implementing the Canton Protocol.

Key Directories:

canton/
├── community/                   # Open-source Canton
│   ├── app/                     # CantonCommunityApp entry point
│   ├── participant/             # Participant node implementation
│   ├── domain/                  # Embedded domain (sequencer/mediator)
│   └── common/src/main/daml/    # Built-in DAML packages
│       └── AdminWorkflows/      # Ping, party replication DARs
├── daml/                        # DAML SDK submodule
├── daml_dependencies.json       # LF library versions
├── VERSION                      # Canton version
└── version.sbt                  # SBT version config

Built-in DARs (embedded in JAR):

• canton-builtin-admin-workflow-ping.dar
• canton-builtin-admin-workflow-party-replication-alpha.dar
• CantonExamples.dar

Enterprise vs Community:

3. Splice (github.com/digital-asset/decentralized-canton-sync)

Purpose: Decentralized synchronizer governance, Amulet (Canton Coin), and network applications.

Key Directories:

decentralized-canton-sync/
├── project/
│   ├── CantonDependencies.scala  # Version config, LF versions
│   └── DamlPlugin.scala          # DAR build logic
├── daml/
│   ├── splice-amulet/            # Canton Coin token contracts
│   ├── splice-wallet/            # Wallet contracts
│   ├── splice-dso-governance/    # DSO governance
│   └── */daml.yaml               # Package configs with --target
├── apps/
│   ├── sv/                       # Super Validator app
│   ├── validator/                # Validator app
│   ├── wallet/                   # Wallet backend
│   └── scan/                     # Payment scan service
├── cluster/images/               # Docker image builds
│   └── canton-community/         # Community participant image
└── daml-compiler-sources.json    # Compiler version reference

Critical Configuration (CantonDependencies.scala):

object CantonDependencies {
  val version: String = "3.4.9"
  val daml_language_versions = Seq("2.1")  // ← LF target version
  val daml_libraries_version = version
  val daml_compiler_version = sys.env("DAML_COMPILER_VERSION")
}

Package Target (daml/splice-amulet/daml.yaml):

sdk-version: 3.3.0-snapshot.20250502.13767.0.v2fc6c7e2
build-options:
  - --target=2.1  # Explicit LF 2.1 target

Version Mapping

*Open-source Splice 0.5.4 ships with SDK snapshot 3.3.0-snapshot.20250502 which predates LF 2.2.

Root Cause (Verified): The public Splice release uses an SDK snapshot from May 2, 2025, but LF 2.2 was added to the SDK on October 3, 2025. Updating to SDK 3.4.9 enables LF 2.2 builds.

Key insight: LF 2.2 is fully available in open-source SDK v3.4.9. The Splice project simply needs to be updated to use the newer SDK.

LF Version Implications

Package ID Derivation

Package IDs are cryptographic hashes derived from:

1. Package source content
2. LF version used (--target)
3. SDK/stdlib versions
4. Dependency package IDs

Changing LF version = Different package IDs = Incompatible packages

Upgrade Validation

Canton validates package upgrades:

• Upgraded packages must use equal or newer LF version
• LF 2.1 package cannot "upgrade" to LF 2.2 package (different IDs)
• Mixing LF versions on same ledger causes validation failures

Building from Open-Source

Community Canton Participant

cd canton
sbt "community/app/assembly"
# Output: community/app/target/scala-2.13/canton-community.jar

Splice Applications

cd decentralized-canton-sync
sbt compile  # Requires DAML_COMPILER_VERSION env var

Building with LF 2.2 (Verified Working)

LF 2.2 is available in SDK v3.4.9. The following steps have been verified to work:

1. Edit project/CantonDependencies.scala:

   val daml_language_versions = Seq("2.2")
   

2. Update nix/daml-compiler-sources.json:

   { "version": "3.4.9" }
   

3. Update all daml/*/daml.yaml files:

   sdk-version: 3.4.9
   build-options:
     - --target=2.2
   

4. Remove invalid warning flags (not present in SDK 3.4.9):

   # Remove -Wno-ledger-time-is-alpha from all daml.yaml files
   

5. Build packages:

   cd decentralized-canton-sync
   nix-shell -p daml-sdk --run "daml build -p daml/splice-util"
   nix-shell -p daml-sdk --run "daml build -p daml/splice-amulet"
   

Verified: splice-util and splice-amulet build successfully with LF 2.2 and SDK 3.4.9.

Fully Open-Source LF 2.2 Build (Verified)

Both Splice and Canton can be built with LF 2.2 from entirely open-source code:

Canton Built-in DARs

Update Canton's daml.yaml files:

cd canton/community
# Update all daml.yaml files to sdk-version: 3.4.9 and --target=2.2
perl -pi -e 's/sdk-version: 3\.3\.0-snapshot\.[^\n]*/sdk-version: 3.4.9/g' **/daml.yaml
perl -pi -e 's/--target=2\.1/--target=2.2/g' **/daml.yaml

Rebuild Canton:

sbt "canton-community-app/assembly"

Verified Results (2025-12-24)

Community-built DARs have identical package IDs to enterprise:

• canton-builtin-admin-workflow-ping-3.4.9-fbeb863dab36da66d99...

This confirms full compatibility with enterprise deployments.

Key Files Reference

Troubleshooting

"Unknown Daml-LF version: 2.2"

• Cause: damlc binary doesn't support 2.2 in supportedOutputVersions
• Check: daml damlc --help for supported targets
• Fix: Use SDK version that includes 2.2, or use 2.1

Package ID Mismatch

• Cause: Different LF versions between builds
• Check: unzip -p package.dar META-INF/MANIFEST.MF | grep Sdk-Version
• Fix: Ensure consistent --target across all builds

Upgrade Validation Failed

• Cause: Trying to swap enterprise (LF 2.2) with community (LF 2.1) packages
• Fix: Use DAR injection to maintain LF 2.2 compatibility

External References

• DAML SDK Releases
• Canton Releases
• Splice Documentation
• DAML-LF Governance
• Canton Network Docs