fix test suite failure when run with LANG=C

Logs/Presence/Pure.hs

@@ -19,6 +19,7 @@ import qualified Data.ByteString.Char8 as C8
 import qualified Data.Attoparsec.ByteString.Lazy as A
 import Data.Attoparsec.ByteString.Char8 (char, anyChar)
 import Data.ByteString.Builder
+import Data.Char
 
 newtype LogInfo = LogInfo { fromLogInfo :: S.ByteString }
 	deriving (Show, Eq, Ord)
@@ -119,8 +120,14 @@ instance Arbitrary LogLine where
 		<*> elements [minBound..maxBound]
 		<*> (LogInfo <$> arbinfo)
 	  where
-		arbinfo = (encodeBS <$> arbitrary) `suchThat`
+	  	-- Avoid newline characters, which cannot appear in 
-			(\b -> C8.notElem '\n' b && C8.notElem '\r' b)
+		-- LogInfo.
+		--
+		-- Avoid non-ascii values because fully arbitrary
+		-- strings may not be encoded using the filesystem
+		-- encoding, which is normally applied to all input.
+		arbinfo = (encodeBS <$> arbitrary `suchThat` all isAscii)
+			`suchThat` (\b -> C8.notElem '\n' b && C8.notElem '\r' b)
 
 prop_parse_build_presence_log :: [LogLine] -> Bool
 prop_parse_build_presence_log l =

doc/bugs/prop__95__parse__95__build__95__presence__95__log_started_to_fail.mdwn

@@ -18,3 +18,4 @@ cron-20210811/build-ubuntu.yaml-374-69466103-success/1_test-annex-more.txt:2021-
 cron-20210812/build-ubuntu.yaml-375-69466103-failed/1_test-annex-more.txt:2021-08-12T02:48:07.7317675Z   name: git-annex-debianstandalone-packages_8.20210803+git45-g6318c0f27_amd64
 ```
 
+> [[fixed|done]] --[[Joey]] 

doc/bugs/prop__95__parse__95__build__95__presence__95__log_started_to_fail/comment_1_32c4300e35453177613bfe1af50e6958._comment

@@ -0,0 +1,46 @@
+[[!comment format=mdwn
+ username="joey"
+ subject="""comment 1"""
+ date="2021-08-18T20:38:06Z"
+ content="""
+The test suite output includes the random seed that allows reproducing
+the failure.
+
+	2021-08-12T02:49:23.2932499Z     prop_parse_build_presence_log:                        FAIL
+	2021-08-12T02:49:23.2934007Z       *** Failed! Exception: 'recoverEncode: invalid argument (invalid character)' (after 3 tests):
+	2021-08-12T02:49:23.2935639Z       Exception thrown while showing test case: 'recoverEncode: invalid argument (invalid character)'
+	2021-08-12T02:49:23.2937094Z       Use --quickcheck-replay=271417 to reproduce.
+
+And git-annex test has to be run with LANG=C for it to fail.
+
+[[!commit fa62c98910746c2c5dda21b3f80effc147a04f65]] is responsible for this
+failure popping up, somehow. I tried reverting that commit, and it fixed
+the failure.
+
+But I don't understand why that commit would cause this problem.
+Also reverting it is not sufficient, because filepath-bytestring includes
+the same change, in its commit 7e88eb5726d8183987455e15d921dd4c5df94674.
+So if the new code is buggy, RawFilePath conversions could also trigger
+similar problems. Also, these changes were a 2x speedup over the old code.
+
+A similar problem was discussed and fixed long ago
+in [[!commit 4e4e11849a0d95389de81461ba2f2a4e0245d3b2]]:
+
+    an Arbitrary String is not necessarily encoded using the filesystem
+    encoding, and in a non-utf8 locale, encodeBS throws an exception on such a
+    string. All I could think to do is limit test data to ascii.
+    
+    This shouldn't be a problem in practice, because the all Strings in
+    git-annex that are not generated by Arbitrary should be loaded in a way
+    that does apply the filesystem encoding.
+
+That makes sense. And it is also encodeBS failing here, in a similar
+situation. But why would the recent change to the implementation of
+encodeBS make it fail, in this case where the old implementation does not?
+
+So I've fixed this by similarly limiting the test to ascii, but I'm unsatisfied
+that the encodeBS implementation change might not break something else. I did
+try, with LANG=C, using git-annex in a repo with some filenames that were
+encoded in unicode, and it round-tripped them fine still, so the change seems
+ok to that extent.
+"""]]