[ANE-Bot] Tolerate Maven plugin scratch dir removed before cleanup

Changelog.md

@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+- Maven: analysis no longer fails with `An exception occurred: /tmp/fossa-maven-... removeDirectoryRecursive:getSymbolicLinkStatus: does not exist (No such file or directory)` when the plugin's scratch directory is removed (e.g. by the OS temp reaper) before cleanup runs; the scratch directory is now cleaned up on a best-effort basis. ([#1771](https://github.com/fossas/fossa-cli/pull/1771))
 - Dart: `pubspec.yaml` files using valid dependency forms the parser previously rejected no longer fail analysis with `Aeson exception: ... empty` or `failed parsing pub package's source!`: a bare dependency with no value (any version), a `version:`-only entry, the `hosted: <url>` shorthand introduced in Dart 2.15, a `hosted:` map without a `version`, and a `git:` map without a `ref`. ([#1760](https://github.com/fossas/fossa-cli/pull/1760))
 - Workflows: `fossa analyze --x-workflow <path>` runs a dependency-usage workflow analyzer through the embedded ficus and records its result in the debug bundle. ([#1761](https://github.com/fossas/fossa-cli/pull/1761))
 - Workflows: the `--x-workflow` result is uploaded to FOSSA against the analyzed revision once the dependency upload succeeds; `--output` runs still upload nothing. ([#1762](https://github.com/fossas/fossa-cli/pull/1762))

src/Strategy/Maven/Plugin.hs

@@ -25,8 +25,9 @@ module Strategy.Maven.Plugin (
 
 import Control.Algebra (Has)
 import Control.Effect.Diagnostics (Diagnostics, ToDiagnostic (renderDiagnostic), recover, warn)
-import Control.Effect.Exception (Lift, bracket)
+import Control.Effect.Exception (Lift)
 import Control.Effect.Lift (sendIO)
+import Control.Effect.Path (withSystemTempDir)
 import Control.Monad (when)
 import Data.Aeson (FromJSON, parseJSON, withObject, (.!=), (.:), (.:?))
 import Data.ByteString (ByteString)
@@ -79,7 +80,6 @@ import Path (
   toFilePath,
   (</>),
  )
-import Path.IO (createTempDir, getTempDir, removeDirRecur)
 import Strategy.Maven.PluginTree (TextArtifact (..), parseTextArtifacts)
 import Strategy.Maven.Pom.PomFile qualified as PomFile
 import System.FilePath qualified as FP
@@ -117,10 +117,13 @@ withUnpackedPlugin ::
   (FP.FilePath -> m a) ->
   m a
 withUnpackedPlugin plugin act =
-  bracket
-    (sendIO (getTempDir >>= \tmp -> createTempDir tmp "fossa-maven"))
-    (sendIO . removeDirRecur)
-    go
+  -- 'withSystemTempDir' removes the scratch directory on a best-effort basis
+  -- (it ignores IO errors during cleanup). A previous hand-rolled
+  -- 'bracket'/'removeDirRecur' cleanup would instead escalate any cleanup
+  -- failure to a fatal, analysis-wide error -- e.g. when the OS temp reaper (or
+  -- a race) removed the directory first, the run died with
+  -- @An exception occurred: /tmp/fossa-maven-... removeDirectoryRecursive:getSymbolicLinkStatus: does not exist@.
+  withSystemTempDir "fossa-maven" go
   where
     go tmpDir = do
       let pluginJarFilepath = fromAbsDir tmpDir FP.</> "plugin.jar"

test/Maven/PluginSpec.hs

@@ -18,13 +18,17 @@ import Strategy.Maven.Plugin (
   VerboseEdge (..),
   VerboseGraph (..),
   augmentWithDuplicateEdges,
+  depGraphPlugin,
   deriveVerboseGraphPaths,
   parsePluginOutput,
   parseVerboseGraphs,
   textArtifactToPluginOutput,
+  withUnpackedPlugin,
  )
 import Strategy.Maven.PluginTree (TextArtifact (..), parseTextArtifact)
 import Strategy.Maven.Pom.PomFile (MavenCoordinate (..), Pom (..), PomBuild (..))
+import System.Directory qualified as Dir
+import System.FilePath qualified as FP
 import Test.Effect (
   expectFatal',
   expectationFailure',
@@ -47,6 +51,22 @@ spec = do
   verboseGraphCollectionSpec
   deriveVerboseGraphPathsSpec
   parsePluginOutputSpec
+  withUnpackedPluginSpec
+
+-- | 'withUnpackedPlugin' unpacks the plugin jar into a scratch directory and
+-- must clean it up on a best-effort basis. If the directory is already gone
+-- when cleanup runs (e.g. an OS temp reaper removed it, or a concurrent task
+-- did), cleanup must not turn that into a fatal, analysis-wide error such as
+-- @An exception occurred: /tmp/fossa-maven-... removeDirectoryRecursive:getSymbolicLinkStatus: does not exist@.
+withUnpackedPluginSpec :: Spec
+withUnpackedPluginSpec =
+  describe "withUnpackedPlugin" $
+    it' "does not fail when the scratch directory is already gone at cleanup time" $ do
+      result <- withUnpackedPlugin depGraphPlugin $ \pluginJarFilepath -> do
+        -- Simulate the scratch directory vanishing before cleanup runs.
+        sendIO $ Dir.removeDirectoryRecursive (FP.takeDirectory pluginJarFilepath)
+        pure (42 :: Int)
+      result `shouldBe'` (42 :: Int)
 
 -- | The @graph@ goal is not an aggregator: in a multi-module build it runs once
 -- per reactor module, writing into each module's own build directory.