From 92e3e17214974e21d90a37e43427ea3681b5cf79 Mon Sep 17 00:00:00 2001
From: savanto <savanto@users.noreply.github.com>
Date: Mon, 30 Jun 2025 16:12:44 -0500
Subject: [PATCH] imp: pivot: Tag name shadowing field name takes precedence
 (#2169)

Tags shadowing field names (eg. `payee`) take precedence during
pivoting. For example, before this change,
```
2025-01-01 CustA
    asset       $100    ; payee:CustA
    asset       $200    ; payee:CustB
    revenue
```
we expect `bal asset --pivot=payee` to produce:
```
                $300  CustA
--------------------
                $300
```

But after this change, we expect:
```
                $100  CustA
                $200  CustB
--------------------
                $300
```

More specific tags take precedence over less specific tags
(ie. posting tags take precedence over transaction tags):

```
2025-01-01 CustA  ; payee:CustB
    asset       $100    ; payee:CustA
    asset       $200    ; payee:CustB
    revenue
```
still results in
```
                $100  CustA
                $200  CustB
--------------------
                $300
```
---
 hledger-lib/Hledger/Data/Journal.hs |  3 ++-
 hledger/test/pivot.test             | 25 +++++++++++++++++++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/hledger-lib/Hledger/Data/Journal.hs b/hledger-lib/Hledger/Data/Journal.hs
index 2d05de1139e..eb676b55f9a 100644
--- a/hledger-lib/Hledger/Data/Journal.hs
+++ b/hledger-lib/Hledger/Data/Journal.hs
@@ -1145,8 +1145,10 @@ pivotAccount fieldortagname p =
 -- "comm" and "cur" are accepted as synonyms meaning the commodity symbol.
 -- Pivoting on an unknown field or tag, or on commodity when there are multiple commodities, returns "".
 -- Pivoting on a tag when there are multiple values for that tag, returns the first value.
+-- Pivoting on a tag name that shadows a field name gives precedence to the tag value.
 pivotComponent :: Text -> Posting -> Text
 pivotComponent fieldortagname p
+  | Just (_, tagvalue) <- postingFindTag fieldortagname p = tagvalue
   | fieldortagname == "code",        Just t <- ptransaction p = tcode t
   | fieldortagname `elem` descnames, Just t <- ptransaction p = tdescription t
   | fieldortagname == "payee",       Just t <- ptransaction p = transactionPayee t
@@ -1156,7 +1158,6 @@ pivotComponent fieldortagname p
   | fieldortagname `elem` commnames = case map acommodity $ amounts $ pamount p of [s] -> s; _ -> unknown
   | fieldortagname == "amt"         = case amounts $ pamount p of [a] -> T.pack $ show $ aquantity a; _ -> unknown
   | fieldortagname == "cost"        = case amounts $ pamount p of [a@Amount{acost=Just _}] -> T.pack $ lstrip $ showAmountCost a; _ -> unknown
-  | Just (_, tagvalue) <- postingFindTag fieldortagname p = tagvalue
   | otherwise = unknown
   where
     descnames = ["desc", "description"]   -- allow "description" for hledger <=1.30 compat
diff --git a/hledger/test/pivot.test b/hledger/test/pivot.test
index e4dae385bbe..0a422bf76ab 100644
--- a/hledger/test/pivot.test
+++ b/hledger/test/pivot.test
@@ -207,3 +207,28 @@ Balance changes in 2025:
  @ $100 ||             2 B 
 --------++-----------------
         || $-210, 1 A, 2 B 
+
+# ** 18. When tag shadows field, tag takes precedence.
+<
+2025-01-01 CustA  ; payee:CustB
+    asset       $100
+    asset       $200
+    revenue    $-300
+
+$ hledger -f- bal asset --pivot=payee
+                $300  CustB
+--------------------
+                $300  
+
+# ** 19. More specific tag takes precedence over less specific (ie. posting tag precedes transaction tag).
+<
+2025-01-01 CustA  ; payee:CustB
+    asset       $100    ; payee:CustA
+    asset       $200    ; payee:CustB
+    revenue    $-300
+
+$ hledger -f- bal asset --pivot=payee
+                $100  CustA
+                $200  CustB
+--------------------
+                $300