From 2a564503fa0fa8772a4ac29b2d97ecf3c1ec331c Mon Sep 17 00:00:00 2001
From: Tom Ellis <tom-git@jaguarpaw.co.uk>
Date: Sat, 17 Aug 2024 09:38:54 +0100
Subject: [PATCH] Don't strip whitespace from stdout/stderr

---
 package.yaml                         |  1 +
 src/System/Process/Typed/Internal.hs | 27 ++++++++++++++++++++-------
 test/System/Process/TypedSpec.hs     | 21 +++++++--------------
 3 files changed, 28 insertions(+), 21 deletions(-)

diff --git a/package.yaml b/package.yaml
index 76bdc96..1a0fee1 100644
--- a/package.yaml
+++ b/package.yaml
@@ -21,6 +21,7 @@ dependencies:
 - stm
 - transformers
 - unliftio-core
+- text >=2.0
 
 library:
   source-dirs: src
diff --git a/src/System/Process/Typed/Internal.hs b/src/System/Process/Typed/Internal.hs
index 4ba505c..fe662c7 100644
--- a/src/System/Process/Typed/Internal.hs
+++ b/src/System/Process/Typed/Internal.hs
@@ -621,15 +621,28 @@ data ExitCodeException = ExitCodeException
 instance Exception ExitCodeException
 instance Show ExitCodeException where
     show ece =
-        let decodeStrip = T.unpack . T.strip . TL.toStrict . TLE.decodeUtf8With lenientDecode
-            stdout = decodeStrip $ eceStdout ece
-            stderr = decodeStrip $ eceStderr ece
-            stdout' = if null stdout
+        let decode = TL.toStrict . TLE.decodeUtf8With lenientDecode
+
+            isAsciiSpace char = case char of
+                                  ' ' -> True
+                                  '\t' -> True
+                                  '\n' -> True
+                                  '\r' -> True
+                                  _ -> False
+            isOnlyAsciiWhitespace = T.null . T.dropAround isAsciiSpace
+
+            stdout = decode $ eceStdout ece
+            stderr = decode $ eceStderr ece
+            stdout' = if isOnlyAsciiWhitespace stdout
                          then []
-                         else ["\n\nStandard output:\n", stdout]
-            stderr' = if null stderr
+                         else [ "\n\nStandard output:\n"
+                              , T.unpack stdout
+                              ]
+            stderr' = if isOnlyAsciiWhitespace stderr
                          then []
-                         else ["\n\nStandard error:\n", stderr]
+                         else [ "\nStandard error:\n"
+                              , T.unpack stderr
+                              ]
         in concat $
             [ "Received "
             , show (eceExitCode ece)
diff --git a/test/System/Process/TypedSpec.hs b/test/System/Process/TypedSpec.hs
index 5626fb7..298e523 100644
--- a/test/System/Process/TypedSpec.hs
+++ b/test/System/Process/TypedSpec.hs
@@ -238,7 +238,7 @@ spec = do
                 ++ "Copied OK\n"
                 ++ "\n"
                 ++ "Standard error:\n"
-                ++ "Uh oh!"
+                ++ "Uh oh!\n"
 
         it "Show only stdout" $ do
             let exitCodeException =
@@ -253,7 +253,7 @@ spec = do
                 ++ "Raw command: show-puppy\n"
                 ++ "\n"
                 ++ "Standard output:\n"
-                ++ "No puppies found???"
+                ++ "No puppies found???\n"
 
         it "Show only stderr" $ do
             let exitCodeException =
@@ -266,17 +266,10 @@ spec = do
             show exitCodeException `shouldBe`
                 "Received ExitFailure 1 when running\n"
                 ++ "Raw command: show-puppy\n"
-                ++ "\n"
                 ++ "Standard error:\n"
-                ++ "No puppies found???"
-
-        it "Show trims stdout/stderr" $ do
-            -- This keeps the `Show` output looking nice regardless of how many
-            -- newlines (if any) the command outputs.
-            --
-            -- This also makes sure that the `Show` output doesn't end with a
-            -- spurious trailing newline, making it easier to compose `Show`
-            -- instances together.
+                ++ "No puppies found???\n"
+
+        it "Show does not trim stdout/stderr" $ do
             let exitCodeException =
                   ExitCodeException
                       { eceExitCode = ExitFailure 1
@@ -289,10 +282,10 @@ spec = do
                 ++ "Raw command: detect-doggies\n"
                 ++ "\n"
                 ++ "Standard output:\n"
-                ++ "puppy\n"
+                ++ "\n\npuppy\n\n \n"
                 ++ "\n"
                 ++ "Standard error:\n"
-                ++ "doggy"
+                ++ "\t \ndoggy\n \t\n"
 
         it "Show displays correctly with no newlines in stdout" $ do
             -- Sometimes, commands don't output _any_ newlines!