Use a code generator for singletons-base's test suite

RyanGlScott · RyanGlScott · commit 26f07f6d8064 · 2024-12-10T07:09:37.000-05:00
This replaces `singletons-base`'s custom `Setup.hs` script with a `cabal` code generator. This finally allows `singletons-base` to have a `Simple` build type, but at the (relatively less extreme) cost of requiring `Cabal-3.8` or later in order to build. Remarkably, everything that the custom `Setup.hs` script did can be done in a much simpler way with a `cabal` code generator, as all of the information that the `singletons-base` test suite needs to invoke GHC can be inferred from the arguments passed to a code generator. One downside is that due to haskell/cabal#8421, the code generator must be implemented in a standalone executable package (`singletons-base-code-generator`). Until that `cabal` issue is fixed, we will need to upload `singletons-base-code-generator` to Hackage with each `singletons` release. Fixes #532.
diff --git a/.github/workflows/haskell-ci.yml b/.github/workflows/haskell-ci.yml
@@ -8,9 +8,9 @@
 #
 # For more information, see https://github.com/haskell-CI/haskell-ci
 #
-# version: 0.19.20240708
+# version: 0.19.20241202
 #
-# REGENDATA ("0.19.20240708",["github","cabal.project"])
+# REGENDATA ("0.19.20241202",["github","cabal.project"])
 #
 name: Haskell-CI
 on:
@@ -90,15 +90,29 @@ jobs:
             allow-failure: false
       fail-fast: false
     steps:
-      - name: apt
+      - name: apt-get install
         run: |
           apt-get update
           apt-get install -y --no-install-recommends gnupg ca-certificates dirmngr curl git software-properties-common libtinfo5 libnuma-dev
+      - name: Install GHCup
+        run: |
           mkdir -p "$HOME/.ghcup/bin"
           curl -sL https://downloads.haskell.org/ghcup/0.1.30.0/x86_64-linux-ghcup-0.1.30.0 > "$HOME/.ghcup/bin/ghcup"
           chmod a+x "$HOME/.ghcup/bin/ghcup"
-          "$HOME/.ghcup/bin/ghcup" install ghc "$HCVER" || (cat "$HOME"/.ghcup/logs/*.* && false)
+      - name: Install cabal-install
+        run: |
           "$HOME/.ghcup/bin/ghcup" install cabal 3.12.1.0 || (cat "$HOME"/.ghcup/logs/*.* && false)
+          echo "CABAL=$HOME/.ghcup/bin/cabal-3.12.1.0 -vnormal+nowrap" >> "$GITHUB_ENV"
+      - name: Install GHC (GHCup)
+        if: matrix.setup-method == 'ghcup'
+        run: |
+          "$HOME/.ghcup/bin/ghcup" install ghc "$HCVER" || (cat "$HOME"/.ghcup/logs/*.* && false)
+          HC=$("$HOME/.ghcup/bin/ghcup" whereis ghc "$HCVER")
+          HCPKG=$(echo "$HC" | sed 's#ghc$#ghc-pkg#')
+          HADDOCK=$(echo "$HC" | sed 's#ghc$#haddock#')
+          echo "HC=$HC" >> "$GITHUB_ENV"
+          echo "HCPKG=$HCPKG" >> "$GITHUB_ENV"
+          echo "HADDOCK=$HADDOCK" >> "$GITHUB_ENV"
         env:
           HCKIND: ${{ matrix.compilerKind }}
           HCNAME: ${{ matrix.compiler }}
@@ -109,21 +123,12 @@ jobs:
           echo "LANG=C.UTF-8" >> "$GITHUB_ENV"
           echo "CABAL_DIR=$HOME/.cabal" >> "$GITHUB_ENV"
           echo "CABAL_CONFIG=$HOME/.cabal/config" >> "$GITHUB_ENV"
-          HCDIR=/opt/$HCKIND/$HCVER
-          HC=$("$HOME/.ghcup/bin/ghcup" whereis ghc "$HCVER")
-          HCPKG=$(echo "$HC" | sed 's#ghc$#ghc-pkg#')
-          HADDOCK=$(echo "$HC" | sed 's#ghc$#haddock#')
-          echo "HC=$HC" >> "$GITHUB_ENV"
-          echo "HCPKG=$HCPKG" >> "$GITHUB_ENV"
-          echo "HADDOCK=$HADDOCK" >> "$GITHUB_ENV"
-          echo "CABAL=$HOME/.ghcup/bin/cabal-3.12.1.0 -vnormal+nowrap" >> "$GITHUB_ENV"
           HCNUMVER=$(${HC} --numeric-version|perl -ne '/^(\d+)\.(\d+)\.(\d+)(\.(\d+))?$/; print(10000 * $1 + 100 * $2 + ($3 == 0 ? $5 != 1 : $3))')
           echo "HCNUMVER=$HCNUMVER" >> "$GITHUB_ENV"
           echo "ARG_TESTS=--enable-tests" >> "$GITHUB_ENV"
           echo "ARG_BENCH=--enable-benchmarks" >> "$GITHUB_ENV"
           echo "HEADHACKAGE=false" >> "$GITHUB_ENV"
           echo "ARG_COMPILER=--$HCKIND --with-compiler=$HC" >> "$GITHUB_ENV"
-          echo "GHCJSARITH=0" >> "$GITHUB_ENV"
         env:
           HCKIND: ${{ matrix.compilerKind }}
           HCNAME: ${{ matrix.compiler }}
@@ -182,6 +187,7 @@ jobs:
           echo "packages: $GITHUB_WORKSPACE/source/./singletons" >> cabal.project
           if [ $((HCNUMVER >= 91000)) -ne 0 ] ; then echo "packages: $GITHUB_WORKSPACE/source/./singletons-th" >> cabal.project ; fi
           if [ $((HCNUMVER >= 91000)) -ne 0 ] ; then echo "packages: $GITHUB_WORKSPACE/source/./singletons-base" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 91000)) -ne 0 ] ; then echo "packages: $GITHUB_WORKSPACE/source/./singletons-base-code-generator" >> cabal.project ; fi
           cat cabal.project
       - name: sdist
         run: |
@@ -199,25 +205,30 @@ jobs:
           echo "PKGDIR_singletons_th=${PKGDIR_singletons_th}" >> "$GITHUB_ENV"
           PKGDIR_singletons_base="$(find "$GITHUB_WORKSPACE/unpacked" -maxdepth 1 -type d -regex '.*/singletons-base-[0-9.]*')"
           echo "PKGDIR_singletons_base=${PKGDIR_singletons_base}" >> "$GITHUB_ENV"
+          PKGDIR_singletons_base_code_generator="$(find "$GITHUB_WORKSPACE/unpacked" -maxdepth 1 -type d -regex '.*/singletons-base-code-generator-[0-9.]*')"
+          echo "PKGDIR_singletons_base_code_generator=${PKGDIR_singletons_base_code_generator}" >> "$GITHUB_ENV"
           rm -f cabal.project cabal.project.local
           touch cabal.project
           touch cabal.project.local
           echo "packages: ${PKGDIR_singletons}" >> cabal.project
           if [ $((HCNUMVER >= 91000)) -ne 0 ] ; then echo "packages: ${PKGDIR_singletons_th}" >> cabal.project ; fi
           if [ $((HCNUMVER >= 91000)) -ne 0 ] ; then echo "packages: ${PKGDIR_singletons_base}" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 91000)) -ne 0 ] ; then echo "packages: ${PKGDIR_singletons_base_code_generator}" >> cabal.project ; fi
           if [ $((HCNUMVER >= 80200)) -ne 0 ] ; then echo "package singletons" >> cabal.project ; fi
           if [ $((HCNUMVER >= 80200)) -ne 0 ] ; then echo "    ghc-options: -Werror=missing-methods" >> cabal.project ; fi
           if [ $((HCNUMVER >= 91000)) -ne 0 ] ; then echo "package singletons-th" >> cabal.project ; fi
           if [ $((HCNUMVER >= 91000)) -ne 0 ] ; then echo "    ghc-options: -Werror=missing-methods" >> cabal.project ; fi
           if [ $((HCNUMVER >= 91000)) -ne 0 ] ; then echo "package singletons-base" >> cabal.project ; fi
           if [ $((HCNUMVER >= 91000)) -ne 0 ] ; then echo "    ghc-options: -Werror=missing-methods" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 91000)) -ne 0 ] ; then echo "package singletons-base-code-generator" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 91000)) -ne 0 ] ; then echo "    ghc-options: -Werror=missing-methods" >> cabal.project ; fi
           cat >> cabal.project <<EOF
           source-repository-package
             type:     git
             location: https://github.com/goldfirere/th-desugar
             tag:      730a0ed799c91324d42b70d3780d6b3215cafc3c
           EOF
-          $HCPKG list --simple-output --names-only | perl -ne 'for (split /\s+/) { print "constraints: any.$_ installed\n" unless /^(Cabal|Cabal-syntax|singletons|singletons-base|singletons-th)$/; }' >> cabal.project.local
+          $HCPKG list --simple-output --names-only | perl -ne 'for (split /\s+/) { print "constraints: any.$_ installed\n" unless /^(Cabal|Cabal-syntax|singletons|singletons-base|singletons-base-code-generator|singletons-th)$/; }' >> cabal.project.local
           cat cabal.project
           cat cabal.project.local
       - name: dump install plan
@@ -248,12 +259,14 @@ jobs:
           if [ $((HCNUMVER >= 91000)) -ne 0 ] ; then ${CABAL} -vnormal check ; fi
           if [ $((HCNUMVER >= 91000)) -ne 0 ] ; then cd ${PKGDIR_singletons_base} || false ; fi
           if [ $((HCNUMVER >= 91000)) -ne 0 ] ; then ${CABAL} -vnormal check ; fi
+          if [ $((HCNUMVER >= 91000)) -ne 0 ] ; then cd ${PKGDIR_singletons_base_code_generator} || false ; fi
+          if [ $((HCNUMVER >= 91000)) -ne 0 ] ; then ${CABAL} -vnormal check ; fi
       - name: haddock
         run: |
           $CABAL v2-haddock --disable-documentation $ARG_COMPILER --with-haddock $HADDOCK $ARG_TESTS $ARG_BENCH all
       - name: save cache
-        uses: actions/cache/save@v4
         if: always()
+        uses: actions/cache/save@v4
         with:
           key: ${{ runner.os }}-${{ matrix.compiler }}-${{ github.sha }}
           path: ~/.cabal/store
diff --git a/cabal.project b/cabal.project
@@ -1,6 +1,7 @@
 packages: ./singletons
           ./singletons-th
           ./singletons-base
+          ./singletons-base-code-generator
 
 source-repository-package
   type: git
diff --git a/singletons-base-code-generator/CHANGES.md b/singletons-base-code-generator/CHANGES.md
@@ -0,0 +1,6 @@
+Changelog for the `singletons-base-code-generator` project
+==========================================================
+
+0.1 [????.??.??]
+----------------
+* Initial release.
diff --git a/singletons-base-code-generator/LICENSE b/singletons-base-code-generator/LICENSE
@@ -0,0 +1,27 @@
+Copyright (c) 2022-2024, Ryan Scott
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice,
+this list of conditions and the following disclaimer in the documentation
+and/or other materials provided with the distribution.
+
+3. Neither the name of the author nor the names of its contributors may be
+used to endorse or promote products derived from this software without
+specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/singletons-base-code-generator/README.md b/singletons-base-code-generator/README.md
@@ -0,0 +1,10 @@
+`singletons-base-code-generator`
+================================
+
+[![Hackage](https://img.shields.io/hackage/v/singletons-base-code-generator.svg)](http://hackage.haskell.org/package/singletons-base-code-generator)
+
+A [`cabal` code
+generator](https://cabal.readthedocs.io/en/stable/cabal-package-description-file.html#pkg-field-test-suite-code-generators)
+used in the test suite for the
+[`singletons-base`](https://hackage.haskell.org/package/singletons-base)
+library.
diff --git a/singletons-base-code-generator/singletons-base-code-generator.cabal b/singletons-base-code-generator/singletons-base-code-generator.cabal
@@ -0,0 +1,43 @@
+cabal-version:  3.8
+name:           singletons-base-code-generator
+version:        0.1
+synopsis:       Code generator for the singletons-base test suite
+homepage:       http://www.github.com/goldfirere/singletons
+category:       Dependent Types
+author:         Ryan Scott <ryan.gl.scott@gmail.com>
+maintainer:     Ryan Scott <ryan.gl.scott@gmail.com>
+bug-reports:    https://github.com/goldfirere/singletons/issues
+stability:      experimental
+tested-with:    GHC == 9.10.1
+extra-doc-files:    CHANGES.md
+extra-source-files: README.md
+license:        BSD-3-Clause
+license-file:   LICENSE
+build-type:     Simple
+description:
+    A [@cabal@ code
+    generator](https://cabal.readthedocs.io/en/stable/cabal-package-description-file.html#pkg-field-test-suite-code-generators)
+    used in the test suite for the
+    [@singletons-base@](https://hackage.haskell.org/package/singletons-base)
+    library.
+
+source-repository this
+  type:     git
+  location: https://github.com/goldfirere/singletons.git
+  subdir:   singletons-base-code-generator
+  tag:      v0.1
+
+source-repository head
+  type:     git
+  location: https://github.com/goldfirere/singletons.git
+  subdir:   singletons-base-code-generator
+  branch:   master
+
+executable singletons-base-code-generator
+  hs-source-dirs:     src
+  ghc-options:        -Wall -Wcompat -threaded
+  default-language:   GHC2021
+  main-is:            SingletonsBaseCodeGenerator.hs
+  build-depends:      base >= 4.20 && < 4.21,
+                      directory >= 1.2 && < 1.4,
+                      filepath >= 1.3 && < 1.6
diff --git a/singletons-base-code-generator/src/SingletonsBaseCodeGenerator.hs b/singletons-base-code-generator/src/SingletonsBaseCodeGenerator.hs
@@ -0,0 +1,62 @@
+-- | A @cabal@ code generator used in the test suite for the @singletons-base@
+-- library. This records all of the GHC flags used when building
+-- @singletons-base@ so that when the test suite invokes GHC, it can find the
+-- locally built version of @singletons-base@ and its dependencies.
+module Main (main) where
+
+import Data.List (isPrefixOf)
+import System.Directory (createDirectoryIfMissing, getCurrentDirectory)
+import System.Environment (getArgs)
+import System.FilePath ((</>), (<.>))
+
+
+main :: IO ()
+main = do
+  -- The directory in which singletons-base and its test suite are located. This
+  -- only works under the assumption that cabal will navigate to that directory
+  -- before invoking the code generator. This is always the case when I've
+  -- tested it, but if this assumption does not hold in general, we may need to
+  -- revisit this assumption.
+  singletonsBaseDir <- getCurrentDirectory
+  args <- getArgs
+  (tgt, rest) <-
+    case args of
+      (tgt:allFlags) -> pure (tgt, allFlags)
+      [] -> fail "Expected at least one argument for code generator"
+  ghcFlags <- takeGhcArgs rest
+  -- Filter out GHC language extensions and warnings, as the singletons-base
+  -- test suite wants to have finer-grained control over these.
+  let ghcFlags' = filter (\flag -> not (isLangExtension flag || isWarning flag)) ghcFlags
+  createDirectoryIfMissing True tgt
+  writeFile (tgt </> generatedFileName <.> "hs") $ unlines
+    [ "module " ++ generatedFileName ++ " where"
+    , ""
+    , "ghcFlags :: [String]"
+    , "ghcFlags = " ++ show ghcFlags'
+    , ""
+    , "rootDir :: FilePath"
+    , "rootDir = " ++ show singletonsBaseDir
+    ]
+  putStrLn generatedFileName
+
+-- | @cabal@ code generators have a convention that GHC-specific arguments are
+-- separated from the rest of the @cabal@-specific arguments using @--@.
+-- Assuming this convention, this function looks up the GHC-specific arguments.
+takeGhcArgs :: [String] -> IO [String]
+takeGhcArgs ("--":xs) = pure xs
+takeGhcArgs (_:xs)    = takeGhcArgs xs
+takeGhcArgs []        = fail "Expected -- to separate arguments"
+
+-- | Returns 'True' if a GHC command-line argument corresponds to a language
+-- extension (e.g., @-XTypeFamilies@).
+isLangExtension :: String -> Bool
+isLangExtension = isPrefixOf "-X"
+
+-- | Returns 'True' if a GHC command-line argument corresponds to a warning flag
+-- (e.g., @-Wtabs@).
+isWarning :: String -> Bool
+isWarning flag = any (`isPrefixOf` flag) ["-W", "-fwarn", "-fno-warn"]
+
+-- | The name of the generated file containing the GHC flags.
+generatedFileName :: String
+generatedFileName = "SingletonsBaseGHCFlags"
diff --git a/singletons-base/CHANGES.md b/singletons-base/CHANGES.md
@@ -3,6 +3,11 @@ Changelog for the `singletons-base` project
 
 next [????.??.??]
 -----------------
+* Remove the use of a custom `Setup.hs` script. This script has now been
+  replaced with a [`cabal` code
+  generator](https://cabal.readthedocs.io/en/stable/cabal-package-description-file.html#pkg-field-test-suite-code-generators)
+  As such, `singletons-base` now requires the use of `Cabal-3.8` or later in
+  order to build.
 * The types of `sError`, `sErrorWithoutStackTrace`, and `sUndefined` are now
   less polymorphic than they were before:
 
diff --git a/singletons-base/Setup.hs b/singletons-base/Setup.hs
diff --git a/singletons-base/singletons-base.cabal b/singletons-base/singletons-base.cabal
diff --git a/singletons-base/tests/SingletonsBaseTestSuiteUtils.hs b/singletons-base/tests/SingletonsBaseTestSuiteUtils.hs
