From db748465a834fcfe09019c0b3aa4b9319594541f Mon Sep 17 00:00:00 2001
From: Simon Michael <simon@joyful.com>
Date: Thu, 17 Oct 2024 21:20:02 -1000
Subject: [PATCH] fix:pager: when the $PAGER is not in PATH, print instead of
 failing

---
 hledger-lib/Hledger/Utils/IO.hs | 16 ++++++++++++++--
 hledger-lib/hledger-lib.cabal   |  6 +++---
 hledger-lib/package.yaml        |  2 +-
 hledger/Hledger/Cli/DocFiles.hs |  1 +
 4 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/hledger-lib/Hledger/Utils/IO.hs b/hledger-lib/Hledger/Utils/IO.hs
index 06d165db2..72b9cfe27 100644
--- a/hledger-lib/Hledger/Utils/IO.hs
+++ b/hledger-lib/Hledger/Utils/IO.hs
@@ -114,7 +114,7 @@ import           String.ANSI
 import           System.Console.ANSI (Color(..),ColorIntensity(..),
   ConsoleLayer(..), SGR(..), hSupportsANSIColor, setSGRCode, getLayerColor)
 import           System.Console.Terminal.Size (Window (Window), size)
-import           System.Directory (getHomeDirectory, getModificationTime)
+import           System.Directory (getHomeDirectory, getModificationTime, findExecutable)
 import           System.Environment (getArgs, lookupEnv, setEnv)
 import           System.FilePath (isRelative, (</>))
 import "Glob"    System.FilePath.Glob (glob)
@@ -202,6 +202,7 @@ setupPager = do
   addR "LESS"
   addR "MORE"
 
+-- related: Hledger.Cli.DocFiles.runPagerForTopic
 -- | Display the given text on the terminal, using the user's $PAGER if the text is taller 
 -- than the current terminal and stdout is interactive and TERM is not "dumb";
 -- except on Windows, where currently we don't attempt to use a pager.
@@ -220,7 +221,18 @@ printOrPage' s = do
   dumbterm <- (== Just "dumb") <$> lookupEnv "TERM"
   -- avoid a pager crash with single-line output, https://github.com/pharpend/pager/issues/2
   let singleline = not $ '\n' `elem` s
-  (if dumbterm || singleline
+  -- avoid a pager crash when PAGER is set to something not in PATH
+  mpagervar <- lookupEnv "PAGER"
+  badpager <-
+    case mpagervar of
+      Nothing -> return False
+      Just p -> do
+        mexe <- findExecutable p
+        case mexe of
+          Just _  -> return False
+          Nothing -> return True
+
+  (if dumbterm || singleline || badpager
   then putStr
   else printOrPage . T.pack)
     s
diff --git a/hledger-lib/hledger-lib.cabal b/hledger-lib/hledger-lib.cabal
index 18b2daacb..cab8fb49c 100644
--- a/hledger-lib/hledger-lib.cabal
+++ b/hledger-lib/hledger-lib.cabal
@@ -138,7 +138,7 @@ library
     , containers >=0.5.9
     , data-default >=0.5
     , deepseq
-    , directory
+    , directory >=1.2.6.1
     , doclayout >=0.3 && <0.6
     , extra >=1.6.3
     , file-embed >=0.0.10
@@ -202,7 +202,7 @@ test-suite doctest
     , containers >=0.5.9
     , data-default >=0.5
     , deepseq
-    , directory
+    , directory >=1.2.6.1
     , doclayout >=0.3 && <0.6
     , doctest >=0.18.1
     , extra >=1.6.3
@@ -269,7 +269,7 @@ test-suite unittest
     , containers >=0.5.9
     , data-default >=0.5
     , deepseq
-    , directory
+    , directory >=1.2.6.1
     , doclayout >=0.3 && <0.6
     , extra >=1.6.3
     , file-embed >=0.0.10
diff --git a/hledger-lib/package.yaml b/hledger-lib/package.yaml
index f0aeed1d1..21a17b7cb 100644
--- a/hledger-lib/package.yaml
+++ b/hledger-lib/package.yaml
@@ -57,7 +57,7 @@ dependencies:
 - data-default >=0.5
 - deepseq
 - Decimal >=0.5.1
-- directory
+- directory >=1.2.6.1
 - doclayout >=0.3 && <0.6
 - file-embed >=0.0.10
 - filepath
diff --git a/hledger/Hledger/Cli/DocFiles.hs b/hledger/Hledger/Cli/DocFiles.hs
index 007c32879..2ddfd6768 100644
--- a/hledger/Hledger/Cli/DocFiles.hs
+++ b/hledger/Hledger/Cli/DocFiles.hs
@@ -109,6 +109,7 @@ runInfoForTopic tool mtopic =
 -- less with any vertical whitespace squashed, case-insensitive searching, the $ regex metacharacter accessible as \$.
 less = "less -s -i --use-backslash"
 
+-- related: Hledger.Utils.IO.pager
 -- | Display plain text help for this tool, scrolled to the given topic if any, using the users $PAGER or "less".
 -- When a topic is provided we always use less, ignoring $PAGER.
 runPagerForTopic :: Tool -> Maybe Topic -> IO ()