Upgrade testscript to cabal v2 and use --keep-going

Some caveats:

  * Cabal version in CI has been bumped to 3.0+ due to need of test
    flags support: haskell/cabal#5455

  * v1-copy was dropped, since it requires v1 build artifacts. There is
    no v2-copy command AFAICT.

  * I don't think there is an equivalent for the v1-install command for
    libraries?

.github/workflows/build.yml

@@ -16,7 +16,7 @@ jobs:
         include:
           - { os: macos-latest, stack: lts-12.26, stack-extra-deps: "bytestring-0.11.3.0, filepath-1.4.100.0, unix-2.8.0.0" }
           - { os: macos-latest, stack: lts-19.21, stack-extra-deps: "bytestring-0.11.3.0, filepath-1.4.100.0, unix-2.8.0.0" }
-          - { os: ubuntu-latest, ghc: 8.4.4, cabal: "2.4", overrides: "before_prepare() { sed -i.bak /utimensat/d configure.ac; }" }
+          - { os: ubuntu-latest, ghc: 8.4.4, cabal: 3.0.0.0, overrides: "before_prepare() { sed -i.bak /utimensat/d configure.ac; }" }
           - { os: ubuntu-latest, ghc: 9.0.1, cabal: 3.4.0.0 }
           - { os: ubuntu-latest, ghc: latest, cabal: latest }
           - { os: windows-latest, stack: lts-12.26, stack-extra-deps: "bytestring-0.11.3.0, filepath-1.4.100.0, time-1.8.0.2, Win32-2.13.3.0", overrides: "before_prepare() { sed -i.bak -e /CreateSymbolicLinkW/d -e /GetFinalPathNameByHandleW/d configure.ac; }" }

tools/testscript

@@ -31,25 +31,22 @@ EOF
         ghc --version
         cabal --version
         tools/retry cabal update
-        cabal v1-install --enable-tests --only-dependencies
+        cabal v2-configure -v2 --enable-tests --ghc-options="$ghcflags"
 
     fi
 }
 
 build() {
     if [ "${STACK_RESOLVER-}" ]; then
-        $stack test --haddock --no-haddock-deps \
+        $stack test --haddock --no-haddock-deps --keep-going \
             --ghc-options "$ghcflags" \
             --test-arguments "$testflags"
         $stack sdist
     else
         testflags=`printf " %s" "$testflags" | sed "s/ / --test-option=/g"`
-        cabal v1-configure -v2 --enable-tests --ghc-options="$ghcflags"
-        cabal v1-build
-        cabal v1-test --show-details=streaming $testflags
+        cabal v2-test --keep-going --test-show-details=streaming $testflags
         cabal check
         cabal v2-sdist
-        cabal v1-copy
         cabal v1-install --force-reinstalls --run-tests dist-newstyle/sdist/*-*.tar.gz
     fi