Don't Glob if Glob Ain't Glob 2: The Globbening

Cabal-tests/tests/UnitTests/Distribution/Simple/Glob.hs

@@ -107,13 +107,13 @@ testMatchesVersion version pat expected = do
           -- check can't identify that kind of match.
           expected' = filter (\case GlobMatchesDirectory _ -> False; _ -> True) expected
       unless (sort expected' == sort actual) $
-        assertFailure $ "Unexpected result (pure matcher): " ++ show actual
+        assertFailure $ "Unexpected result (pure matcher): " ++ show actual ++ "\nExpected: " ++ show expected
     checkIO globPat =
       withSystemTempDirectory "globstar-sample" $ \tmpdir -> do
         makeSampleFiles tmpdir
         actual <- runDirFileGlob Verbosity.normal (Just version) tmpdir globPat
         unless (isEqual actual expected) $
-          assertFailure $ "Unexpected result (impure matcher): " ++ show actual
+          assertFailure $ "Unexpected result (impure matcher): " ++ show actual ++ "\nExpected: " ++ show expected
 
 testFailParseVersion :: CabalSpecVersion -> FilePath -> GlobSyntaxError -> Assertion
 testFailParseVersion version pat expected =

Cabal/src/Distribution/Simple/Glob.hs

@@ -370,7 +370,6 @@ runDirFileGlob verbosity mspec rawRoot pat = do
       "Null dir passed to runDirFileGlob; interpreting it "
         ++ "as '.'. This is probably an internal error."
   let root = if null rawRoot then "." else rawRoot
-  debug verbosity $ "Expanding glob '" ++ show (pretty pat) ++ "' in directory '" ++ root ++ "'."
   -- This function might be called from the project root with dir as
   -- ".". Walking the tree starting there involves going into .git/
   -- and dist-newstyle/, which is a lot of work for no reward, so
@@ -379,7 +378,7 @@ runDirFileGlob verbosity mspec rawRoot pat = do
   -- the whole directory if *, and just the specific file if it's a
   -- literal.
   let
-    (prefixSegments, variablePattern) = splitConstantPrefix pat
+    (prefixSegments, pathOrVariablePattern) = splitConstantPrefix pat
     joinedPrefix = joinPath prefixSegments
 
     -- The glob matching function depends on whether we care about the cabal version or not
@@ -431,17 +430,37 @@ runDirFileGlob verbosity mspec rawRoot pat = do
       concat <$> traverse (\subdir -> go globPath (dir </> subdir)) subdirs
     go GlobDirTrailing dir = return [GlobMatch dir]
 
-  directoryExists <- doesDirectoryExist (root </> joinedPrefix)
-  if directoryExists
-    then go variablePattern joinedPrefix
-    else return [GlobMissingDirectory joinedPrefix]
+  case pathOrVariablePattern of
+    Left filename -> do
+      let filepath = joinedPrefix </> filename
+      debug verbosity $ "Treating glob as filepath literal '" ++ filepath ++ "' in directory '" ++ root ++ "'."
+      directoryExists <- doesDirectoryExist (root </> filepath)
+      if directoryExists
+        then pure [GlobMatchesDirectory filepath]
+        else do
+          exist <- doesFileExist (root </> filepath)
+          pure $
+            if exist
+              then [GlobMatch filepath]
+              else []
+    Right variablePattern -> do
+      debug verbosity $ "Expanding glob '" ++ show (pretty pat) ++ "' in directory '" ++ root ++ "'."
+      directoryExists <- doesDirectoryExist (root </> joinedPrefix)
+      if directoryExists
+        then go variablePattern joinedPrefix
+        else return [GlobMissingDirectory joinedPrefix]
   where
     -- \| Extract the (possibly null) constant prefix from the pattern.
     -- This has the property that, if @(pref, final) = splitConstantPrefix pat@,
     -- then @pat === foldr GlobDir final pref@.
-    splitConstantPrefix :: Glob -> ([FilePath], Glob)
-    splitConstantPrefix = unfoldr' step
+    splitConstantPrefix :: Glob -> ([FilePath], Either FilePath Glob)
+    splitConstantPrefix = fmap literalize . unfoldr' step
       where
+        literalize (GlobFile [Literal filename]) =
+          Left filename
+        literalize glob =
+          Right glob
+
         step (GlobDir [Literal seg] pat') = Right (seg, pat')
         step pat' = Left pat'
 

cabal-testsuite/PackageTests/Check/ConfiguredPackage/Paths/AbsolutePath/cabal.out

@@ -1,6 +1,6 @@
 # cabal check
 These warnings may cause trouble when distributing the package:
-Warning: [glob-missing-dir] In 'extra-source-files': the pattern '/home/user/file' attempts to match files in the directory '/home/user', but there is no directory by that name.
+Warning: [no-glob-match] In 'extra-source-files': the pattern '/home/user/file' does not match any files.
 The following errors will cause portability problems on other environments:
 Error: [absolute-path] 'extra-source-files: /home/user/file' specifies an absolute path, but the 'extra-source-files' field must use relative paths.
 Error: [malformed-relative-path] 'extra-source-files: /home/user/file' is not a good relative path: "posix absolute path"