Exceptions in DAML

[sofiafaro-da]

Over-arching ticket for implementing exceptions in DAML ("one ring to rule them all"), so we have an issue number to keep track of work to be done. See also the exception milestone.

TODO:

• update LF specification
  • syntax & semantics of exception handling (implemented in First batch of formal exception semantics #8068 DAML-LF spec: Incorporate Remy's feedback on exceptions #8111)
  • update existing primitives & constructs to throw more appropriate exceptions
• update LF protobuf (implemented in Update protobuf for exceptions. #8087)
• change DAML-LF AST
  • on Haskell side (implemented in Add exceptions in DAML-LF AST (Haskell side) #8112)
  • on Scala side
• update type checker
  • on Haskell side (Add exceptions in DAML-LF AST (Haskell side) #8112, Add exception type coherence check on Haskell side #8137)
  • on Scala side
• update serializability checker
  • on Haskell side (Add exceptions in DAML-LF AST (Haskell side) #8112, Add serializability check for exceptions. #8151)
  • on Scala side
• update LF engine
  • implement exception builtins
  • implement exception handling
  • update existing primitives to throw appropriate exceptions
• update standard library
  • add DAML_EXCEPTIONS feature (Add DAML_EXCEPTIONS feature. #8114)
  • add DA.Exception module (Add exception modules in daml-stdlib. #8023)
  • run through existing standard library functions and see if they should throw more appropriate exceptions (Make succ/pred throw an ArithmeticError on overflow. #9783)
• update surface syntax
  • prepare examples of surface syntax & its desugaring
  • implement syntax for declaring exception types
  • implement try-catch block syntax
  • update daml studio language file to highlight exception keywords
  • (not implemented, left as separate issue) implement more powerful ensure statement (issue More powerful ensure statements #3571 but read exception design doc)
• update data-dependencies
  • recognize built-in exception types
  • re-export exceptions
  • add a test that involves raising and catching built-in exceptions across data-dependency boundaries (Add a data-dependencies test for stdlib exceptions. #9799)
• release a new LF version
  • update the LF version for the DAML_EXCEPTIONS feature in DA.Daml.Lf.Ast.Version
  • update the LF version for DA.Internal.Exception in the "generate stable package" rule
  • update stable package test (compiler/damlc/tests/src/stable-packages.sh) and other references to exception stable packages.
• update ledger-api-test-tool with tests that involve catching and throwing exceptions

[cocreature]

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