Detect implicit cabal cradle in the absence of cabal.project (#221)

* Detect implicit cabal cradle in the absence of cabal.project

A cabal cradle doesn't need a cabal.project file and isn't guaranteed to
have one either. This improves the implicit cradle search for cabal by
falling back to finding .cabal files if hie-bios couldn't find any
cabal.project files.
Because it falls back, if hie-bios tries to query a multi-package cabal
project with a nested cabal package, it will still find use the "larger"
cradle with the upper cabal.project file. See the
implicit-cabal-deep-project test project for an example of this.

* Copy test projects over to temporary directory

This prevents the cabal.project/hie.yaml of hie-bios's source tree from
interfering with the cradle stuff

.github/workflows/haskell.yml

@@ -32,7 +32,7 @@ jobs:
         key: ${{ runner.OS }}-${{ matrix.ghc }}-cabal-0
 
     - name: Run ShellCheck
-      uses: ludeeus/action-shellcheck@master
+      uses: ludeeus/action-shellcheck@2f2aa0d
       if: matrix.os == 'ubuntu-latest'
       with:
         ignore: tests

hie-bios.cabal

@@ -119,6 +119,14 @@ Extra-Source-Files:     ChangeLog
                         tests/projects/implicit-cabal/cabal.project
                         tests/projects/implicit-cabal/implicit-cabal.cabal
                         tests/projects/implicit-cabal/Main.hs
+                        tests/projects/implicit-cabal-no-project/implicit-cabal-no-project.cabal
+                        tests/projects/implicit-cabal-no-project/Main.hs
+                        tests/projects/implicit-cabal-deep-project/README
+                        tests/projects/implicit-cabal-deep-project/implicit-cabal-deep-project.cabal
+                        tests/projects/implicit-cabal-deep-project/Main.hs
+                        tests/projects/implicit-cabal-deep-project/cabal.project
+                        tests/projects/implicit-cabal-deep-project/foo/foo.cabal
+                        tests/projects/implicit-cabal-deep-project/foo/Main.hs
                         tests/projects/implicit-stack/Setup.hs
                         tests/projects/implicit-stack/implicit-stack.cabal
                         tests/projects/implicit-stack/Main.hs
@@ -229,6 +237,7 @@ test-suite bios-tests
       hie-bios,
       filepath,
       directory,
+      temporary,
       ghc
 
   hs-source-dirs: tests/

src/HIE/Bios/Cradle.hs

@@ -544,9 +544,9 @@ removeVerbosityOpts = filter ((&&) <$> (/= "-v0") <*> (/= "-w"))
 
 
 cabalWorkDir :: FilePath -> MaybeT IO FilePath
-cabalWorkDir = findFileUpwards isCabal
-  where
-    isCabal name = name == "cabal.project"
+cabalWorkDir wdir =
+      findFileUpwards (== "cabal.project") wdir
+  <|> findFileUpwards (\fp -> takeExtension fp == ".cabal") wdir
 
 ------------------------------------------------------------------------
 -- | Stack Cradle

tests/projects/failing-cabal/failing-cabal.cabal

@@ -7,7 +7,7 @@ build-type:          Simple
 
 library
   exposed-modules:     MyLib
-  build-depends:       base >=4.13 && <4.14,
+  build-depends:       base >=4,
                        containers < 1 && > 1
                        --         ^^^^^^^^^^ <<< Invalid constraint
   default-language:    Haskell2010

tests/projects/implicit-cabal-deep-project/Main.hs

@@ -0,0 +1 @@
+main = pure ()

tests/projects/implicit-cabal-deep-project/README

@@ -0,0 +1,3 @@
+Here we are testing that if we have a nested cabal package but a cabal.project
+a directory above it, hie-bios will implicitly pick up the cabal.project and
+NOT the nested cabal package

tests/projects/implicit-cabal-deep-project/cabal.project

@@ -0,0 +1,2 @@
+packages: .
+          foo

tests/projects/implicit-cabal-deep-project/foo/Main.hs

@@ -0,0 +1 @@
+main = pure ()

tests/projects/implicit-cabal-deep-project/foo/foo.cabal

@@ -0,0 +1,9 @@
+cabal-version:       >=1.10
+name:                foo
+version:             0.1.0.0
+build-type:          Simple
+
+executable foo
+  main-is:             Main.hs
+  build-depends:       base >=4
+  default-language:    Haskell2010

tests/projects/implicit-cabal-deep-project/implicit-cabal-deep-project.cabal

@@ -0,0 +1,8 @@
+cabal-version:       >=1.10
+name:                implicit-cabal-deep-project
+version:             0.1.0.0
+build-type:          Simple
+executable foo
+  main-is:             Main.hs
+  build-depends:       base >=4
+  default-language:    Haskell2010

tests/projects/implicit-cabal-no-project/Main.hs

@@ -0,0 +1 @@
+main = pure ()

tests/projects/implicit-cabal-no-project/implicit-cabal-no-project.cabal

@@ -0,0 +1,8 @@
+cabal-version:       >=1.10
+name:                implicit-cabal-no-project
+version:             0.1.0.0
+build-type:          Simple
+executable foo
+  main-is:             Main.hs
+  build-depends:       base >=4
+  default-language:    Haskell2010