From e6bf04fce3c93630957339483a2aba7dd0e2fda0 Mon Sep 17 00:00:00 2001
From: Stephen Morgan <morgan.stephen99@gmail.com>
Date: Sun, 13 Mar 2022 19:02:44 +1100
Subject: [PATCH] fix: aliases: Make sure we can escape forward slashes in
 account aliases, but otherwise the regular expression handler handles
 escapes.

---
 hledger-lib/Hledger/Read/Common.hs |  8 +++++---
 hledger/test/account-aliases.test  | 30 ++++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+), 3 deletions(-)

diff --git a/hledger-lib/Hledger/Read/Common.hs b/hledger-lib/Hledger/Read/Common.hs
index 0e0f4f627..8846ac4cb 100644
--- a/hledger-lib/Hledger/Read/Common.hs
+++ b/hledger-lib/Hledger/Read/Common.hs
@@ -1517,15 +1517,17 @@ regexaliasp = do
   -- dbgparse 0 "regexaliasp"
   (off1, off2, re) <- between (char '/') (char '/') $ do
     off1 <- getOffset
-    re <- some $ noneOf ("/\\\n\r" :: [Char])  -- paranoid: don't try to read past line end
-             <|> (char '\\' *> anySingle)      -- allow escaping any character
+    re <- fmap T.concat . some $
+             (T.singleton <$> noneOf ("/\\\n\r" :: [Char]))               -- paranoid: don't try to read past line end
+             <|> string "\\/"                                             -- allow escaping forward slashes
+             <|> (liftM2 T.cons (char '\\') (T.singleton <$> anySingle))  -- Otherwise leave backslashes in
     off2 <- getOffset
     return (off1, off2, re)
   skipNonNewlineSpaces
   char '='
   skipNonNewlineSpaces
   repl <- anySingle `manyTill` eolof
-  case toRegexCI $ T.pack re of
+  case toRegexCI re of
     Right r -> return $! RegexAlias r repl
     Left e  -> customFailure $! parseErrorAtRegion off1 off2 e
 
diff --git a/hledger/test/account-aliases.test b/hledger/test/account-aliases.test
index 09cd2e9b7..58b3770c4 100644
--- a/hledger/test/account-aliases.test
+++ b/hledger/test/account-aliases.test
@@ -267,3 +267,33 @@ $ hledger -f- print
     b
 
 >=0
+
+# 19. Make sure you can escape special regexp characters.
+<
+alias /\./ = :
+
+2021-01-01
+  hi.there    1
+  b
+
+$ hledger -f- print
+2021-01-01
+    hi:there               1
+    b
+
+>=0
+
+# 20. Including backslashes
+<
+alias /\\/ = :
+
+2021-01-01
+  hi\there    1
+  b
+
+$ hledger -f- print
+2021-01-01
+    hi:there               1
+    b
+
+>=0