Backport #10800: cabal-install: Fix the directory the build folder is created in (#10888)

* testsuite: Set TMPDIR to a specific folder rather than the test root

If things start getting created in the TMPDIR, then it is better to not
place them directly in the project root next to the source and test
files. This also makes it easier to write tests which are sensitive to
what is created in the CWD.

(cherry picked from commit c64a32d)

# Conflicts:
#	cabal-testsuite/PackageTests/HaddockKeepTmpsCustom/cabal.test.hs
#	cabal-testsuite/PackageTests/HaddockKeepsTmps/cabal.test.hs
#	cabal-testsuite/src/Test/Cabal/Monad.hs

* cabal-install: Fix the directory the build folder is created in

Clearly this path needs to be relative to the CWD, and the correct
offset is passed as the `srcdir` parameter.

Fixes #10772

(cherry picked from commit 85ef030)

* Add tests which check build/dist-newstyle folders are not created with v2-run

The existing test CmdRun/Script is modified to test the case when v2-run
is executed in a project context. This test checks that a "build" folder
is not created in the CWD (#10772)

A new test is also added which checks what happens in the "no context"
case. A separate bug was fixed in this area recently but no test added
which verifies the change (#10686)

(cherry picked from commit 852430c)

* Quickfix the conflicts in tests; let's see if it works

* Remove test updates for which we lack machinery

* Remove the added test and all the modifications to an old test

---------

Co-authored-by: Matthew Pickering <[email protected]>
Co-authored-by: Mikolaj Konarski <[email protected]>

Author: 3 people

cabal-install/src/Distribution/Client/ProjectBuilding/UnpackedPackage.hs

@@ -447,7 +447,7 @@ buildInplaceUnpackedPackage
     -- TODO: [code cleanup] there is duplication between the
     --      distdirlayout and the builddir here builddir is not
     --      enough, we also need the per-package cachedir
-    createDirectoryIfMissingVerbose verbosity True $ getSymbolicPath builddir
+    createDirectoryIfMissingVerbose verbosity True $ interpretSymbolicPath (Just srcdir) builddir
     createDirectoryIfMissingVerbose
       verbosity
       True

cabal-testsuite/src/Test/Cabal/Monad.hs

@@ -34,6 +34,7 @@ module Test.Cabal.Monad (
     testPrefixDir,
     testLibInstallDir,
     testDistDir,
+    testSystemTmpDir,
     testPackageDbDir,
     testRepoDir,
     testKeysDir,
@@ -406,6 +407,10 @@ runTestM mode m =
                         -- effect on Windows.
                         , ("CABAL_DIR", Just (testCabalDir env))
                         , ("CABAL_CONFIG", Just (testUserCabalConfigFile env))
+                        -- Set `TMPDIR` so that temporary files aren't created in the global `TMPDIR`.
+                        , ("TMPDIR", Just (testSystemTmpDir env))
+                        -- Windows uses `TMP` for the `TMPDIR`.
+                        , ("TMP", Just (testSystemTmpDir env))
                         ],
                     testShouldFail = False,
                     testRelativeCurrentDir = ".",
@@ -544,6 +549,7 @@ initWorkDir :: TestM ()
 initWorkDir = do
     env <- getTestEnv
     liftIO $ createDirectoryIfMissing True (testWorkDir env)
+    liftIO $ createDirectoryIfMissing True (testSystemTmpDir env)
 
 
 
@@ -820,6 +826,11 @@ testName env = testSubName env <.> testMode env
 testWorkDir :: TestEnv -> FilePath
 testWorkDir env = testTmpDir env </> (testName env <.> "dist")
 
+-- The folder which TMPDIR is set to.
+-- This is different to testTmpDir, which is the folder which is the test is run from.
+testSystemTmpDir :: TestEnv -> FilePath
+testSystemTmpDir env = testWorkDir env </> "tmp"
+
 -- | The absolute prefix where installs go.
 testPrefixDir :: TestEnv -> FilePath
 testPrefixDir env = testWorkDir env </> "usr"

changelog.d/pr-10800

@@ -0,0 +1,12 @@
+synopsis: Fix regression where 'build' folder was created in CWD when running a standlone script.
+packages: cabal-install
+prs: #10800
+issues: #10772
+significance:
+
+description: {
+
+Fix a regression where the `build` folder was created in the current directory
+when running a standalone script.
+
+}