use openTempFile from file-io

And follow-on changes.

Note that relatedTemplate was changed to operate on a RawFilePath, and
so when it counts the length, it is now the number of bytes, not the
number of code points. This will just make it truncate shorter strings
in some cases, the truncation is still unicode aware.

When not building with the OsPath flag, toOsPath . fromRawFilePath and
fromRawFilePath . fromOsPath do extra conversions back and forth between
String and ByteString. That overhead could be avoided, but that's the
non-optimised build mode, so didn't bother.

Sponsored-by: unqueued

Assistant/Upgrade.hs

@@ -189,7 +189,7 @@ upgradeToDistribution newdir cleanup distributionfile = do
 	 - into place. -}
 	unpack = liftIO $ do
 		olddir <- oldVersionLocation
-		withTmpDirIn (fromRawFilePath $ parentDir $ toRawFilePath newdir) "git-annex.upgrade" $ \tmpdir -> do
+		withTmpDirIn (fromRawFilePath $ parentDir $ toRawFilePath newdir) (toOsPath $ toRawFilePath "git-annex.upgrade") $ \tmpdir -> do
 			let tarball = tmpdir </> "tar"
 			-- Cannot rely on filename extension, and this also
 			-- avoids problems if tar doesn't support transparent
@@ -323,7 +323,7 @@ downloadDistributionInfo :: Assistant (Maybe GitAnnexDistribution)
 downloadDistributionInfo = do
 	uo <- liftAnnex Url.getUrlOptions
 	gpgcmd <- liftAnnex $ gpgCmd <$> Annex.getGitConfig
-	liftIO $ withTmpDir "git-annex.tmp" $ \tmpdir -> do
+	liftIO $ withTmpDir (toOsPath (toRawFilePath "git-annex.tmp")) $ \tmpdir -> do
 		let infof = tmpdir </> "info"
 		let sigf = infof ++ ".sig"
 		ifM (isRight <$> Url.download nullMeterUpdate Nothing distributionInfoUrl infof uo
@@ -361,7 +361,7 @@ upgradeSupported = False
 verifyDistributionSig :: GpgCmd -> FilePath -> IO Bool
 verifyDistributionSig gpgcmd sig = readProgramFile >>= \case
 	Just p | isAbsolute p ->
-		withUmask 0o0077 $ withTmpDir "git-annex-gpg.tmp" $ \gpgtmp -> do
+		withUmask 0o0077 $ withTmpDir (toOsPath (toRawFilePath "git-annex-gpg.tmp")) $ \gpgtmp -> do
 			let trustedkeys = takeDirectory p </> "trustedkeys.gpg"
 			boolGpgCmd gpgcmd
 				[ Param "--no-default-keyring"