Include fixed subRegex from regex-compat-tdfa

Upstream looks unmaintained, and we only use a single function anyway.
The package did not build with ghc 9, so we include a fixed version of
that function.

cabal-testsuite/cabal-testsuite.cabal

@@ -67,8 +67,9 @@ library
     , filepath              ^>= 1.3.0.1 || ^>= 1.4.0.0
     , optparse-applicative  ^>= 0.14.3.0 || ^>=0.15.1.0 || ^>=0.16.0.0
     , process               ^>= 1.1.0.2 || ^>= 1.2.0.0 || ^>= 1.4.2.0 || ^>= 1.6.1.0
-    , regex-compat-tdfa     ^>= 0.95.1.4
+    , regex-base            ^>= 0.94.0.1
     , regex-tdfa            ^>= 1.2.3.1 || ^>=1.3.1.0
+    , array                 ^>= 0.4.0.1 || ^>= 0.5.0.0
     , temporary             ^>= 1.3
     , text                  ^>= 1.2.3.1
     , transformers          ^>= 0.3.0.0 || ^>= 0.4.2.0 || ^>= 0.5.2.0

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

@@ -11,9 +11,11 @@ import Distribution.Pretty
 import Distribution.Package
 import Distribution.System
 
-import qualified Data.Foldable as F
+import Text.Regex.Base
+import Text.Regex.TDFA
+import Data.Array ((!))
 
-import Text.Regex
+import qualified Data.Foldable as F
 
 normalizeOutput :: NormalizerEnv -> String -> String
 normalizeOutput nenv =
@@ -80,6 +82,41 @@ posixSpecialChars = ".^$*+?()[{\\|"
 posixRegexEscape :: String -> String
 posixRegexEscape = concatMap (\c -> if c `elem` posixSpecialChars then ['\\', c] else [c])
 
+-- From regex-compat-tdfa by Christopher Kuklewicz and shelarcy, BSD-3-Clause
+-------------------------
+
 resub :: String {- search -} -> String {- replace -} -> String {- input -} -> String
-resub search replace s =
-    subRegex (mkRegex search) s replace
+resub _ _ "" = ""
+resub regexp repl inp =
+  let compile _i str [] = \ _m ->  (str ++)
+      compile i str (("\\", (off, len)) : rest) =
+        let i' = off + len
+            pre = take (off - i) str
+            str' = drop (i' - i) str
+        in if null str' then \ _m -> (pre ++) . ('\\' :)
+             else \ m -> (pre ++) . ('\\' :) . compile i' str' rest m
+      compile i str ((xstr, (off, len)) : rest) =
+        let i' = off + len
+            pre = take (off - i) str
+            str' = drop (i' - i) str
+            x = read xstr
+        in if null str' then \ m -> (pre++) . (fst (m ! x) ++)
+             else \ m -> (pre ++) . (fst (m ! x) ++) . compile i' str' rest m
+      compiled :: MatchText String -> String -> String
+      compiled = compile 0 repl findrefs where
+        -- bre matches a backslash then capture either a backslash or some digits
+        bre = mkRegex "\\\\(\\\\|[0-9]+)"
+        findrefs = map (\m -> (fst (m ! 1), snd (m ! 0))) (matchAllText bre repl)
+      go _i str [] = str
+      go i str (m : ms) =
+        let (_, (off, len)) = m ! 0
+            i' = off + len
+            pre = take (off - i) str
+            str' = drop (i' - i) str
+        in if null str' then pre ++ compiled m ""
+             else pre ++ compiled m (go i' str' ms)
+  in go 0 inp (matchAllText (mkRegex regexp) inp)
+
+mkRegex :: String -> Regex
+mkRegex s = makeRegexOpts opt defaultExecOpt s
+  where opt = defaultCompOpt { newSyntax = True, multiline = True }