Hack around wrong .mix directories for tests (backport #7493)

Cabal/src/Distribution/Simple/Hpc.hs

@@ -68,7 +68,29 @@ mixDir :: FilePath  -- ^ \"dist/\" prefix
        -> Way
        -> FilePath  -- ^ Component name
        -> FilePath  -- ^ Directory containing test suite's .mix files
-mixDir distPref way name = hpcDir distPref way </> "mix" </> name
+mixDir distPref way name = hpcDir distPrefBuild way </> "mix" </> name
+ where
+  -- This is a hack for HPC over test suites, needed to match the directory
+  -- where HPC saves and reads .mix files when the main library of the same
+  -- package is being processed, perhaps in a previous cabal run (#5213).
+  -- E.g., @distPref@ may be
+  -- @./dist-newstyle/build/x86_64-linux/ghc-9.0.1/cabal-gh5213-0.1/t/tests@
+  -- but the path where library mix files reside has two less components
+  -- at the end (@t/tests@) and this reduced path needs to be passed to
+  -- both @hpc@ and @ghc@. For non-default optimization levels, the path
+  -- suffix is one element longer and the extra path element needs
+  -- to be preserved.
+  distPrefElements = splitDirectories distPref
+  distPrefBuild = case drop (length distPrefElements - 3) distPrefElements of
+    ["t", _, "noopt"] ->
+      joinPath $ take (length distPrefElements - 3) distPrefElements
+                 ++ ["noopt"]
+    ["t", _, "opt"] ->
+      joinPath $ take (length distPrefElements - 3) distPrefElements
+                 ++ ["opt"]
+    [_, "t", _] ->
+      joinPath $ take (length distPrefElements - 2) distPrefElements
+    _ -> distPref
 
 tixDir :: FilePath  -- ^ \"dist/\" prefix
        -> Way

cabal-testsuite/PackageTests/Regression/T5213/cabal-gh5213.cabal

@@ -0,0 +1,29 @@
+-- Initial cabal-gh5213.cabal generated by cabal init.  For further
+-- documentation, see http://haskell.org/cabal/users-guide/
+
+name:                cabal-gh5213
+version:             0.1
+-- synopsis:
+-- description:
+license:             BSD3
+author:              Ryan Scott
+maintainer:          ryan.gl.scott@gmail.com
+-- copyright:
+category:            Testing
+build-type:          Simple
+cabal-version:       >=1.10
+
+library
+  exposed-modules:     CabalGH5213Exposed
+  other-modules:       CabalGH5213Other
+  -- other-extensions:
+  build-depends:       base >= 4 && < 5
+  hs-source-dirs:      src
+  default-language:    Haskell2010
+
+test-suite tests
+  main-is:             Main.hs
+  type:                exitcode-stdio-1.0
+  build-depends:       base, cabal-gh5213
+  hs-source-dirs:      tests
+  default-language:    Haskell2010

cabal-testsuite/PackageTests/Regression/T5213/cabal.out

@@ -0,0 +1,19 @@
+# cabal new-test
+Resolving dependencies...
+Build profile: -w ghc-<GHCVER> -O1
+In order, the following will be built:
+ - cabal-gh5213-0.1 (lib) (first run)
+ - cabal-gh5213-0.1 (test:tests) (first run)
+Configuring library for cabal-gh5213-0.1..
+Preprocessing library for cabal-gh5213-0.1..
+Building library for cabal-gh5213-0.1..
+Configuring test suite 'tests' for cabal-gh5213-0.1..
+Preprocessing test suite 'tests' for cabal-gh5213-0.1..
+Building test suite 'tests' for cabal-gh5213-0.1..
+Running 1 test suites...
+Test suite tests: RUNNING...
+Test suite tests: PASS
+Test suite logged to: <ROOT>/cabal.dist/work/./dist/build/<ARCH>/ghc-<GHCVER>/cabal-gh5213-0.1/t/tests/test/cabal-gh5213-0.1-tests.log
+Test coverage report written to <ROOT>/cabal.dist/work/./dist/build/<ARCH>/ghc-<GHCVER>/cabal-gh5213-0.1/t/tests/hpc/vanilla/html/tests/hpc_index.html
+1 of 1 test suites (1 of 1 test cases) passed.
+Package coverage report written to <ROOT>/cabal.dist/work/./dist/build/<ARCH>/ghc-<GHCVER>/cabal-gh5213-0.1/t/tests/hpc/vanilla/html/cabal-gh5213-0.1/hpc_index.html

cabal-testsuite/PackageTests/Regression/T5213/cabal.project

@@ -0,0 +1,4 @@
+packages: .
+
+package cabal-gh5213
+  library-coverage: true

cabal-testsuite/PackageTests/Regression/T5213/cabal.test.hs

@@ -0,0 +1,2 @@
+import Test.Cabal.Prelude
+main = cabalTest $ cabal "new-test" []

cabal-testsuite/PackageTests/Regression/T5213/src/CabalGH5213Exposed.hs

@@ -0,0 +1,6 @@
+module CabalGH5213Exposed where
+
+import CabalGH5213Other
+
+foo :: Int
+foo = bar

cabal-testsuite/PackageTests/Regression/T5213/src/CabalGH5213Other.hs

@@ -0,0 +1,4 @@
+module CabalGH5213Other where
+
+bar :: Int
+bar = 42

cabal-testsuite/PackageTests/Regression/T5213/tests/Main.hs

@@ -0,0 +1,6 @@
+module Main where
+
+import CabalGH5213Exposed
+
+main :: IO ()
+main = print foo

cabal-testsuite/PackageTests/Regression/T5213ExeCoverage/cabal-gh5213.cabal

@@ -0,0 +1,29 @@
+-- Initial cabal-gh5213.cabal generated by cabal init.  For further
+-- documentation, see http://haskell.org/cabal/users-guide/
+
+name:                cabal-gh5213
+version:             0.1
+-- synopsis:
+-- description:
+license:             BSD3
+author:              Ryan Scott
+maintainer:          ryan.gl.scott@gmail.com
+-- copyright:
+category:            Testing
+build-type:          Simple
+cabal-version:       >=1.10
+
+library
+  exposed-modules:     CabalGH5213Exposed
+  other-modules:       CabalGH5213Other
+  -- other-extensions:
+  build-depends:       base >= 4 && < 5
+  hs-source-dirs:      src
+  default-language:    Haskell2010
+
+test-suite tests
+  main-is:             Main.hs
+  type:                exitcode-stdio-1.0
+  build-depends:       base, cabal-gh5213
+  hs-source-dirs:      tests
+  default-language:    Haskell2010

cabal-testsuite/PackageTests/Regression/T5213ExeCoverage/cabal.out

@@ -0,0 +1,19 @@
+# cabal new-test
+Resolving dependencies...
+Build profile: -w ghc-<GHCVER> -O1
+In order, the following will be built:
+ - cabal-gh5213-0.1 (lib) (first run)
+ - cabal-gh5213-0.1 (test:tests) (first run)
+Configuring library for cabal-gh5213-0.1..
+Preprocessing library for cabal-gh5213-0.1..
+Building library for cabal-gh5213-0.1..
+Configuring test suite 'tests' for cabal-gh5213-0.1..
+Preprocessing test suite 'tests' for cabal-gh5213-0.1..
+Building test suite 'tests' for cabal-gh5213-0.1..
+Running 1 test suites...
+Test suite tests: RUNNING...
+Test suite tests: PASS
+Test suite logged to: <ROOT>/cabal.dist/work/./dist/build/<ARCH>/ghc-<GHCVER>/cabal-gh5213-0.1/t/tests/noopt/test/cabal-gh5213-0.1-tests.log
+Test coverage report written to <ROOT>/cabal.dist/work/./dist/build/<ARCH>/ghc-<GHCVER>/cabal-gh5213-0.1/t/tests/noopt/hpc/vanilla/html/tests/hpc_index.html
+1 of 1 test suites (1 of 1 test cases) passed.
+Package coverage report written to <ROOT>/cabal.dist/work/./dist/build/<ARCH>/ghc-<GHCVER>/cabal-gh5213-0.1/t/tests/noopt/hpc/vanilla/html/cabal-gh5213-0.1/hpc_index.html

cabal-testsuite/PackageTests/Regression/T5213ExeCoverage/cabal.project

@@ -0,0 +1,5 @@
+packages: .
+
+package cabal-gh5213
+  coverage: True
+  optimization: False

cabal-testsuite/PackageTests/Regression/T5213ExeCoverage/cabal.test.hs

@@ -0,0 +1,2 @@
+import Test.Cabal.Prelude
+main = cabalTest $ cabal "new-test" []

cabal-testsuite/PackageTests/Regression/T5213ExeCoverage/src/CabalGH5213Exposed.hs

@@ -0,0 +1,6 @@
+module CabalGH5213Exposed where
+
+import CabalGH5213Other
+
+foo :: Int
+foo = bar

cabal-testsuite/PackageTests/Regression/T5213ExeCoverage/src/CabalGH5213Other.hs

@@ -0,0 +1,4 @@
+module CabalGH5213Other where
+
+bar :: Int
+bar = 42

cabal-testsuite/PackageTests/Regression/T5213ExeCoverage/tests/Main.hs

@@ -0,0 +1,6 @@
+module Main where
+
+import CabalGH5213Exposed
+
+main :: IO ()
+main = print foo

changelog.d/pr-7493

@@ -0,0 +1,10 @@
+synopsis: Fix `cabal test --enable-library-coverage` for other-modules
+packages: Cabal
+prs: #7493
+issues: #5213
+description: {
+
+- Fix `cabal test --enable-library-coverage` for libraries with nonempty other-modules field.
+- Due to a hack, this breaks coverage whenever the used Haskell compiler is called 't' (for a non-hacky fix we should rework HPC directories, possibly enabling multilib in the process, see #6440 and #6397).
+
+}