Add the ci flag and fix every warning it turns up

example/app/Main.hs

@@ -1,15 +1,13 @@
-module Main where
+module Main (main) where
 
 import Network.FTP.Client
 import qualified Network.FTP.Client.Conduit as FC
 import Conduit
-import Data.ByteString.Char8 (ByteString)
 import qualified Data.ByteString.Char8 as C
-import Data.Monoid ((<>))
 
 main :: IO ()
-main = withFTPS "hostname.com" 21 $ \h welcome -> do
-    login h "username" "password"
+main = withFTPS "hostname.com" 21 $ \h _welcome -> do
+    _ <- login h "username" "password"
     runConduitRes
         $ FC.mlsd h "."
         .| mapC (C.pack . (<> "\n") . show)

example/example.cabal

@@ -19,21 +19,36 @@ source-repository head
   type: git
   location: https://github.com/flipstone/ftp-client
 
+flag ci
+  description: More strict ghc options used for development and ci, not intended for end-use.
+  manual: True
+  default: False
+
 executable example-exe
   main-is: Main.hs
   other-modules:
       Paths_example
   hs-source-dirs:
       app
-  ghc-options: -threaded -rtsopts -with-rtsopts=-N
   build-depends:
       base
     , bytestring
     , conduit
-    , containers
     , ftp-client
     , ftp-client-conduit
   default-language: Haskell2010
+  if flag(ci)
+    ghc-options: -O2 -threaded -rtsopts -with-rtsopts=-N -Wall -Werror -Wcompat -Widentities -Winvalid-haddock -Wmissing-local-signatures -Wmissing-export-lists -Wpartial-fields -Wmissed-specialisations -Wno-implicit-prelude -Wno-safe -Wno-unsafe -Wunused-packages
+    if impl (ghc < 9.4)
+      ghc-options: -Wno-unticked-promoted-constructors
+    if impl (ghc >= 9.4)
+      ghc-options: -Wimplicit-lift -Woperator-whitespace -Wredundant-bang-patterns -Wredundant-strictness-flags
+    if impl (ghc >= 9.8)
+      ghc-options: -Wincomplete-export-warnings -Wmissing-poly-kind-signatures -Wterm-variable-capture
+    if impl (ghc >= 9.10)
+      ghc-options: -Wdefaulted-exception-context
+  else
+    ghc-options: -threaded -rtsopts -with-rtsopts=-N
 
 test-suite example-test
   type: exitcode-stdio-1.0
@@ -42,7 +57,18 @@ test-suite example-test
       Paths_example
   hs-source-dirs:
       test
-  ghc-options: -threaded -rtsopts -with-rtsopts=-N
   build-depends:
       base
   default-language: Haskell2010
+  if flag(ci)
+    ghc-options: -threaded -rtsopts -with-rtsopts=-N -Wall -Werror -Wcompat -Widentities -Winvalid-haddock -Wmissing-local-signatures -Wmissing-export-lists -Wpartial-fields -Wmissed-specialisations -Wno-implicit-prelude -Wno-safe -Wno-unsafe
+    if impl (ghc < 9.4)
+      ghc-options: -Wno-unticked-promoted-constructors
+    if impl (ghc >= 9.4)
+      ghc-options: -Wimplicit-lift -Woperator-whitespace -Wredundant-bang-patterns -Wredundant-strictness-flags
+    if impl (ghc >= 9.8)
+      ghc-options: -Wincomplete-export-warnings -Wmissing-poly-kind-signatures -Wterm-variable-capture
+    if impl (ghc >= 9.10)
+      ghc-options: -Wdefaulted-exception-context
+  else
+    ghc-options: -threaded -rtsopts -with-rtsopts=-N

example/package.yaml

@@ -10,31 +10,114 @@ category:            Web
 
 git: https://github.com/flipstone/ftp-client
 
+flags:
+  ci:
+    description: More strict ghc options used for development and ci, not intended for end-use.
+    manual: true
+    default: false
+
 executables:
   example-exe:
     main: Main.hs
     source-dirs: app
     language: Haskell2010
-    ghc-options:
-      - -threaded
-      - -rtsopts
-      - -with-rtsopts=-N
     dependencies:
       - base
       - ftp-client
       - ftp-client-conduit
       - conduit
       - bytestring
-      - containers
+    when:
+      - condition: flag(ci)
+        then:
+          ghc-options:
+            - -O2
+            - -threaded
+            - -rtsopts
+            - -with-rtsopts=-N
+            - -Wall
+            - -Werror
+            - -Wcompat
+            - -Widentities
+            - -Winvalid-haddock
+            - -Wmissing-local-signatures
+            - -Wmissing-export-lists
+            - -Wpartial-fields
+            - -Wmissed-specialisations
+            - -Wno-implicit-prelude
+            - -Wno-safe
+            - -Wno-unsafe
+            - -Wunused-packages
+          when:
+            - condition: impl (ghc < 9.4)
+              ghc-options:
+                - -Wno-unticked-promoted-constructors
+            - condition: impl (ghc >= 9.4)
+              ghc-options:
+                - -Wimplicit-lift
+                - -Woperator-whitespace
+                - -Wredundant-bang-patterns
+                - -Wredundant-strictness-flags
+            - condition: impl (ghc >= 9.8)
+              ghc-options:
+                - -Wincomplete-export-warnings
+                - -Wmissing-poly-kind-signatures
+                - -Wterm-variable-capture
+            - condition: impl (ghc >= 9.10)
+              ghc-options:
+                - -Wdefaulted-exception-context
+        else:
+          ghc-options:
+            - -threaded
+            - -rtsopts
+            - -with-rtsopts=-N
 
 tests:
   example-test:
     main: Spec.hs
     source-dirs: test
     language: Haskell2010
-    ghc-options:
-      - -threaded
-      - -rtsopts
-      - -with-rtsopts=-N
     dependencies:
       - base
+    when:
+      - condition: flag(ci)
+        then:
+          ghc-options:
+            - -threaded
+            - -rtsopts
+            - -with-rtsopts=-N
+            - -Wall
+            - -Werror
+            - -Wcompat
+            - -Widentities
+            - -Winvalid-haddock
+            - -Wmissing-local-signatures
+            - -Wmissing-export-lists
+            - -Wpartial-fields
+            - -Wmissed-specialisations
+            - -Wno-implicit-prelude
+            - -Wno-safe
+            - -Wno-unsafe
+          when:
+            - condition: impl (ghc < 9.4)
+              ghc-options:
+                - -Wno-unticked-promoted-constructors
+            - condition: impl (ghc >= 9.4)
+              ghc-options:
+                - -Wimplicit-lift
+                - -Woperator-whitespace
+                - -Wredundant-bang-patterns
+                - -Wredundant-strictness-flags
+            - condition: impl (ghc >= 9.8)
+              ghc-options:
+                - -Wincomplete-export-warnings
+                - -Wmissing-poly-kind-signatures
+                - -Wterm-variable-capture
+            - condition: impl (ghc >= 9.10)
+              ghc-options:
+                - -Wdefaulted-exception-context
+        else:
+          ghc-options:
+            - -threaded
+            - -rtsopts
+            - -with-rtsopts=-N

example/test/Spec.hs

@@ -1,2 +1,4 @@
+module Main (main) where
+
 main :: IO ()
 main = putStrLn "Test suite not yet implemented"

ftp-client-conduit/CHANGELOG.md

@@ -1,5 +1,20 @@
 # Changelog for ftp-client-conduit
 
+## 0.5.0.7
+
+* Add the missing upper bounds on `bytestring`, `conduit` and `exceptions`.
+
+* Replace conduit's deprecated `Producer` and `Consumer` synonyms with
+  `ConduitT` in the exported signatures of `nlst`, `retr`, `list`, `stor` and
+  `mlsd`. The type variables are left free, so the exported types are unchanged
+  -- `Producer m o` is `forall i. ConduitT i o m ()`, not `ConduitT () o m ()`.
+
+* Raise the `conduit` lower bound to `>= 1.3`. `ConduitT` arrived in conduit
+  1.3, so the previous `>= 1.1` allowed dependency selections that cannot
+  compile the signatures above. The bounds audit only added the missing upper
+  halves; this is the lower half that replacing `Producer` and `Consumer`
+  invalidated.
+
 ## 0.5.0.6
 
 * Correct the `resourcet` bound. `>= 1.2 && < 1.3` excluded `resourcet-1.3.0`,

ftp-client-conduit/ftp-client-conduit.cabal

@@ -5,7 +5,7 @@ cabal-version: 1.12
 -- see: https://github.com/sol/hpack
 
 name:           ftp-client-conduit
-version:        0.5.0.6
+version:        0.5.0.7
 synopsis:       Transfer file with FTP and FTPS with Conduit
 description:    ftp-client is a library for communicating with an FTP server. It works over both a clear channel or TLS. ftp-client-conduit uses conduit to stream files and data in constant space.
 category:       Web
@@ -30,6 +30,11 @@ source-repository head
   type: git
   location: https://github.com/flipstone/ftp-client
 
+flag ci
+  description: More strict ghc options used for development and ci, not intended for end-use.
+  manual: True
+  default: False
+
 library
   exposed-modules:
       Network.FTP.Client.Conduit
@@ -38,17 +43,26 @@ library
   hs-source-dirs:
       src
   default-extensions:
-      RankNTypes
       OverloadedStrings
   build-depends:
       base >=4.16 && <5
-    , bytestring
-    , conduit >=1.1
+    , bytestring >=0.10.8.2 && <0.13
+    , conduit ==1.3.*
     , crypton-connection >=0.3 && <0.5
-    , exceptions
+    , exceptions >=0.10.3 && <0.11
     , ftp-client ==0.5.*
     , resourcet >=1.2 && <1.4
   default-language: Haskell2010
+  if flag(ci)
+    ghc-options: -O2 -Wall -Werror -Wcompat -Widentities -Winvalid-haddock -Wmissing-local-signatures -Wmissing-export-lists -Wpartial-fields -Wmissed-specialisations -Wno-implicit-prelude -Wno-safe -Wno-unsafe -Wunused-packages
+    if impl (ghc < 9.4)
+      ghc-options: -Wno-unticked-promoted-constructors
+    if impl (ghc >= 9.4)
+      ghc-options: -Wimplicit-lift -Woperator-whitespace -Wredundant-bang-patterns -Wredundant-strictness-flags
+    if impl (ghc >= 9.8)
+      ghc-options: -Wincomplete-export-warnings -Wmissing-poly-kind-signatures -Wterm-variable-capture
+    if impl (ghc >= 9.10)
+      ghc-options: -Wdefaulted-exception-context
 
 test-suite ftp-conduit-test
   type: exitcode-stdio-1.0
@@ -57,8 +71,19 @@ test-suite ftp-conduit-test
       Paths_ftp_client_conduit
   hs-source-dirs:
       test
-  ghc-options: -threaded -rtsopts -with-rtsopts=-N
   build-depends:
       base >=4.16 && <5
     , ftp-client-conduit
   default-language: Haskell2010
+  if flag(ci)
+    ghc-options: -threaded -rtsopts -with-rtsopts=-N -Wall -Werror -Wcompat -Widentities -Winvalid-haddock -Wmissing-local-signatures -Wmissing-export-lists -Wpartial-fields -Wmissed-specialisations -Wno-implicit-prelude -Wno-safe -Wno-unsafe
+    if impl (ghc < 9.4)
+      ghc-options: -Wno-unticked-promoted-constructors
+    if impl (ghc >= 9.4)
+      ghc-options: -Wimplicit-lift -Woperator-whitespace -Wredundant-bang-patterns -Wredundant-strictness-flags
+    if impl (ghc >= 9.8)
+      ghc-options: -Wincomplete-export-warnings -Wmissing-poly-kind-signatures -Wterm-variable-capture
+    if impl (ghc >= 9.10)
+      ghc-options: -Wdefaulted-exception-context
+  else
+    ghc-options: -threaded -rtsopts -with-rtsopts=-N