Extend trigger compat tests to be agnostic to high-level changes (#7828)

The trigger runner (delibaretely) only cares about the high-level
API. This means that we can change the high-level API without breaking
backwards compatibility in the runner. However, we do of course have
to change the trigger code written in the high-level API.

This PR addresses this by making the code depend on the
version. Unfortunately we cannot use CPP here (something I don’t say
very often) so this is done in a Bazel function.

The last low-level breaking change was the change to `CommandId`
generation so we go back to that.

changelog_begin
changelog_end

compatibility/BUILD

@@ -79,12 +79,13 @@ config_setting(
     if versions.is_at_least(sdk_version, platform_version)
 ]
 
-last_pre_7632_trigger_version = "1.7.0-snapshot.20201013.5418.0.bda13392"
+# Change to `CommandId` generation
+first_post_7587_trigger_version = "1.7.0-snapshot.20201012.5405.0.af92198d"
 
 [
     daml_trigger_dar(sdk_version)
     for sdk_version in sdk_versions
-    if not versions.is_at_most(last_pre_7632_trigger_version, sdk_version)
+    if versions.is_at_least(first_post_7587_trigger_version, sdk_version)
 ]
 
 [
@@ -97,7 +98,7 @@ last_pre_7632_trigger_version = "1.7.0-snapshot.20201013.5418.0.bda13392"
     # Test that the DAML trigger runner can run DARs built with an older SDK
     # version. I.e. where the runner version is at least the SDK version or
     # more recent.
-    if (not versions.is_at_most(last_pre_7632_trigger_version, sdk_version)) and
+    if versions.is_at_least(first_post_7587_trigger_version, sdk_version) and
        versions.is_at_least(sdk_version, platform_version)
 ]
 

compatibility/bazel_tools/daml_trigger/daml_trigger.bzl

@@ -5,7 +5,69 @@ load(
     "@daml//bazel_tools/client_server:client_server_test.bzl",
     "client_server_test",
 )
-load("//bazel_tools:versions.bzl", "version_to_name")
+load("//bazel_tools:versions.bzl", "version_to_name", "versions")
+
+def copy_trigger_src(sdk_version):
+    # To avoid having to mess with Bazel’s escaping, avoid `$` and backticks.
+    # We can’t use CPP to make this nicer unfortunately since this doesn’t work
+    # with an installed SDK.
+    return """
+module CopyTrigger where
+
+import DA.List hiding (dedup)
+import Templates
+import Daml.Trigger
+
+copyTrigger : Trigger ()
+copyTrigger = Trigger
+  {{ initialize = pure ()
+  , updateState = \\_message {acsArg} -> pure ()
+  , rule = copyRule
+  , registeredTemplates = AllInDar
+  , heartbeat = None
+  }}
+
+copyRule party {acsArg} {stateArg} = do
+  subscribers : [(ContractId Subscriber, Subscriber)] <- {query} {acsArg}
+  originals : [(ContractId Original, Original)] <- {query} {acsArg}
+  copies : [(ContractId Copy, Copy)] <- {query} {acsArg}
+
+  let ownedSubscribers = filter (\\(_, s) -> s.subscribedTo == party) subscribers
+  let ownedOriginals = filter (\\(_, o) -> o.owner == party) originals
+  let ownedCopies = filter (\\(_, c) -> c.original.owner == party) copies
+
+  let subscribingParties = map (\\(_, s) -> s.subscriber) ownedSubscribers
+
+  let groupedCopies : [[(ContractId Copy, Copy)]]
+      groupedCopies = groupOn snd (sortOn snd ownedCopies)
+  let copiesToKeep = map head groupedCopies
+  let archiveDuplicateCopies = concatMap tail groupedCopies
+
+  let archiveMissingOriginal = filter (\\(_, c) -> notElem c.original (map snd ownedOriginals)) copiesToKeep
+  let archiveMissingSubscriber = filter (\\(_, c) -> notElem c.subscriber subscribingParties) copiesToKeep
+  let archiveCopies = dedup (map fst (archiveDuplicateCopies <> archiveMissingOriginal <> archiveMissingSubscriber))
+
+  forA archiveCopies (\\cid -> dedupExercise cid Archive)
+
+  let neededCopies = [Copy m o | (_, m) <- ownedOriginals, o <- subscribingParties]
+  let createCopies = filter (\\c -> notElem c (map snd copiesToKeep)) neededCopies
+  mapA dedupCreate createCopies
+  pure ()
+
+dedup : Eq k => [k] -> [k]
+dedup [] = []
+dedup (x :: xs) = x :: dedup (filter (/= x) xs)
+""".format(
+        stateArg = "_" if versions.is_at_most(last_pre_7674_version, sdk_version) else "",
+        acsArg = "acs" if versions.is_at_most(last_pre_7632_version, sdk_version) else "",
+        query = "(pure . getContracts)" if versions.is_at_most(last_pre_7632_version, sdk_version) else "query",
+    )
+
+# Removal of state argument.
+last_pre_7674_version = "1.7.0-snapshot.20201013.5418.0.bda13392"
+
+# Removal of ACS argument
+last_pre_7632_version = "1.7.0-snapshot.20201012.5405.0.af92198d"
 
 def daml_trigger_dar(sdk_version):
     daml = "@daml-sdk-{sdk_version}//:daml".format(
@@ -16,8 +78,8 @@ def daml_trigger_dar(sdk_version):
             sdk_version = version_to_name(sdk_version),
         ),
         srcs = [
-            "//bazel_tools/daml_trigger:example/src/CopyTrigger.daml",
             "//bazel_tools/daml_trigger:example/src/TestScript.daml",
+            "//bazel_tools/daml_trigger:example/src/Templates.daml",
         ],
         outs = ["trigger-example-{sdk_version}.dar".format(
             sdk_version = version_to_name(sdk_version),
@@ -29,8 +91,9 @@ TMP_DIR=$$(mktemp -d)
 cleanup() {{ rm -rf $$TMP_DIR; }}
 trap cleanup EXIT
 mkdir -p $$TMP_DIR/src
-cp -L $(location //bazel_tools/daml_trigger:example/src/CopyTrigger.daml) $$TMP_DIR/src/
+echo "{copy_trigger}" > $$TMP_DIR/src/CopyTrigger.daml
 cp -L $(location //bazel_tools/daml_trigger:example/src/TestScript.daml) $$TMP_DIR/src/
+cp -L $(location //bazel_tools/daml_trigger:example/src/Templates.daml) $$TMP_DIR/src/
 cat <<EOF >$$TMP_DIR/daml.yaml
 sdk-version: {sdk_version}
 name: trigger-example
@@ -46,6 +109,7 @@ $(location {daml}) build --project-root=$$TMP_DIR -o $$PWD/$(OUTS)
 """.format(
             daml = daml,
             sdk_version = sdk_version,
+            copy_trigger = copy_trigger_src(sdk_version),
         ),
     )
 

compatibility/bazel_tools/daml_trigger/example/src/CopyTrigger.daml

@@ -1,109 +0,0 @@
--- Copyright (c) 2020 Digital Asset (Switzerland) GmbH and/or its affiliates. All rights reserved.
--- SPDX-License-Identifier: Apache-2.0
-
-
-module CopyTrigger where
-
-import DA.List hiding (dedup)
-
-import Daml.Trigger
-
--- ORIGINAL_TEMPLATE_BEGIN
-template Original
-  with
-    owner : Party
-    name : Text
-    textdata : Text
-  where
-    signatory owner
-
-    key (owner, name) : (Party, Text)
-    maintainer key._1
--- ORIGINAL_TEMPLATE_END
-
-deriving instance Ord Original
-
--- SUBSCRIBER_TEMPLATE_BEGIN
-template Subscriber
-  with
-    subscriber : Party
-    subscribedTo : Party
-  where
-    signatory subscriber
-    observer subscribedTo
-    key (subscriber, subscribedTo) : (Party, Party)
-    maintainer key._1
--- SUBSCRIBER_TEMPLATE_END
-
--- COPY_TEMPLATE_BEGIN
-template Copy
-  with
-    original : Original
-    subscriber : Party
-  where
-    signatory (signatory original)
-    observer subscriber
--- COPY_TEMPLATE_END
-
-deriving instance Ord Copy
-
--- TRIGGER_BEGIN
-copyTrigger : Trigger ()
-copyTrigger = Trigger
-  { initialize = pure ()
-  , updateState = \_message -> pure ()
-  , rule = copyRule
-  , registeredTemplates = AllInDar
-  , heartbeat = None
-  }
--- TRIGGER_END
-
--- RULE_SIGNATURE_BEGIN
-copyRule : Party -> TriggerA () ()
-copyRule party = do
--- RULE_SIGNATURE_END
--- ACS_QUERY_BEGIN
-  subscribers : [(ContractId Subscriber, Subscriber)] <- query @Subscriber
-  originals : [(ContractId Original, Original)] <- query @Original
-  copies : [(ContractId Copy, Copy)] <- query @Copy
--- ACS_QUERY_END
-
--- ACS_FILTER_BEGIN
-  let ownedSubscribers = filter (\(_, s) -> s.subscribedTo == party) subscribers
-  let ownedOriginals = filter (\(_, o) -> o.owner == party) originals
-  let ownedCopies = filter (\(_, c) -> c.original.owner == party) copies
--- ACS_FILTER_END
-
--- SUBSCRIBING_PARTIES_BEGIN
-  let subscribingParties = map (\(_, s) -> s.subscriber) ownedSubscribers
--- SUBSCRIBING_PARTIES_END
-
--- GROUP_COPIES_BEGIN
-  let groupedCopies : [[(ContractId Copy, Copy)]]
-      groupedCopies = groupOn snd $ sortOn snd $ ownedCopies
-  let copiesToKeep = map head groupedCopies
-  let archiveDuplicateCopies = concatMap tail groupedCopies
--- GROUP_COPIES_END
-
--- ARCHIVE_COPIES_BEGIN
-  let archiveMissingOriginal = filter (\(_, c) -> c.original `notElem` map snd ownedOriginals) copiesToKeep
-  let archiveMissingSubscriber = filter (\(_, c) -> c.subscriber `notElem` subscribingParties) copiesToKeep
-  let archiveCopies = dedup $ map fst $ archiveDuplicateCopies <> archiveMissingOriginal <> archiveMissingSubscriber
--- ARCHIVE_COPIES_END
-
--- ARCHIVE_COMMAND_BEGIN
-  forA archiveCopies $ \cid -> dedupExercise cid Archive
--- ARCHIVE_COMMAND_END
-
--- CREATE_COPIES_BEGIN
-  let neededCopies = [Copy m o | (_, m) <- ownedOriginals, o <- subscribingParties]
-  let createCopies = filter (\c -> c `notElem` map snd copiesToKeep) neededCopies
-  mapA dedupCreate createCopies
--- CREATE_COPIES_END
-  pure ()
-
--- | The dedup function from DA.List requires an Ord constraint which we do not have for `ContractId k`. Therefore,
--- we resort to the n^2 version for now. Once we have Maps we can use those to implement a more efficient dedup.
-dedup : Eq k => [k] -> [k]
-dedup [] = []
-dedup (x :: xs) = x :: dedup (filter (/= x) xs)

compatibility/bazel_tools/daml_trigger/example/src/Templates.daml

@@ -0,0 +1,44 @@
+-- Copyright (c) 2020 Digital Asset (Switzerland) GmbH and/or its affiliates. All rights reserved.
+-- SPDX-License-Identifier: Apache-2.0
+
+module Templates where
+
+-- ORIGINAL_TEMPLATE_BEGIN
+template Original
+  with
+    owner : Party
+    name : Text
+    textdata : Text
+  where
+    signatory owner
+
+    key (owner, name) : (Party, Text)
+    maintainer key._1
+-- ORIGINAL_TEMPLATE_END
+
+deriving instance Ord Original
+
+-- SUBSCRIBER_TEMPLATE_BEGIN
+template Subscriber
+  with
+    subscriber : Party
+    subscribedTo : Party
+  where
+    signatory subscriber
+    observer subscribedTo
+    key (subscriber, subscribedTo) : (Party, Party)
+    maintainer key._1
+-- SUBSCRIBER_TEMPLATE_END
+
+-- COPY_TEMPLATE_BEGIN
+template Copy
+  with
+    original : Original
+    subscriber : Party
+  where
+    signatory (signatory original)
+    observer subscriber
+-- COPY_TEMPLATE_END
+
+deriving instance Ord Copy
+

compatibility/bazel_tools/daml_trigger/example/src/TestScript.daml

@@ -3,7 +3,7 @@
 
 module TestScript where
 
-import CopyTrigger
+import Templates
 import DA.Assert
 import DA.Time
 import Daml.Script