From 8121673c7f266550e7b4f3f66c6e3938a6b78899 Mon Sep 17 00:00:00 2001
From: KtorZ <matthias.benkort@gmail.com>
Date: Thu, 11 Aug 2022 11:43:26 +0200
Subject: [PATCH] Enforce backward-compatibility when encoding NominalDiffTime.

  Keep encoding as integer when the value is a whole number of seconds. Otherwise, this may break clients down the line.
---
 clients/TypeScript/packages/schema/src/index.ts |  2 +-
 docs/static/ogmios.wsp.json                     | 10 ++++------
 server/src/Ogmios/Data/Json/Prelude.hs          | 11 +++++++++--
 server/test/unit/Ogmios/Data/JsonSpec.hs        |  2 +-
 4 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/clients/TypeScript/packages/schema/src/index.ts b/clients/TypeScript/packages/schema/src/index.ts
index 279c8e58e1..374cada53d 100644
--- a/clients/TypeScript/packages/schema/src/index.ts
+++ b/clients/TypeScript/packages/schema/src/index.ts
@@ -330,7 +330,7 @@ export type RelativeTime = number;
  */
 export type QueryUnavailableInCurrentEra = "QueryUnavailableInCurrentEra";
 /**
- * A slot length, in seconds.
+ * A slot length, in seconds. Starting from v5.5.4, this can be a floating number. Before v5.5.4, the floating value would be rounded to the nearest second.
  */
 export type SlotLength = number;
 /**
diff --git a/docs/static/ogmios.wsp.json b/docs/static/ogmios.wsp.json
index 0b75decf53..9186fc1056 100644
--- a/docs/static/ogmios.wsp.json
+++ b/docs/static/ogmios.wsp.json
@@ -3641,10 +3641,9 @@
     }
 
   , "RelativeTime":
-    { "type": "integer"
-    , "description": "A time in seconds relative to another one (typically, system start or era start)."
+    { "type": "number"
+    , "description": "A time in seconds relative to another one (typically, system start or era start). Starting from v5.5.4, this can be a floating number. Before v5.5.4, the floating value would be rounded to the nearest second."
     , "minimum": 0
-    , "maximum": 18446744073709552999
     }
 
   , "Relay":
@@ -4169,9 +4168,8 @@
     }
 
   , "SlotLength":
-    { "type": "integer"
-    , "description": "A slot length, in seconds."
-    , "maximum": 18446744073709552000
+    { "type": "number"
+    , "description": "A slot length, in seconds. Starting from v5.5.4, this can be a floating number. Before v5.5.4, the floating value would be rounded to the nearest second."
     }
 
   , "SoftwareVersion":
diff --git a/server/src/Ogmios/Data/Json/Prelude.hs b/server/src/Ogmios/Data/Json/Prelude.hs
index e699da226a..96e9f8266f 100644
--- a/server/src/Ogmios/Data/Json/Prelude.hs
+++ b/server/src/Ogmios/Data/Json/Prelude.hs
@@ -125,6 +125,8 @@ import Data.ByteString.Bech32
     ( HumanReadablePart, encodeBech32 )
 import Data.IP
     ( IPv4, IPv6 )
+import Data.Ratio
+    ( (%) )
 import Data.Scientific
     ( Scientific )
 import Data.Sequence.Strict
@@ -295,8 +297,13 @@ encodeNatural =
 {-# INLINABLE encodeNatural #-}
 
 encodeNominalDiffTime :: NominalDiffTime -> Json
-encodeNominalDiffTime =
-    Json.double . fromRational . toRational
+encodeNominalDiffTime t =
+    -- TODO / NOTE: Backward-compatibility prior to v5.5.4. Should encode only
+    -- as Double in v6+
+    if i % 1 == r then Json.integer i else Json.double (fromRational r)
+  where
+    r = toRational t
+    i = round t
 {-# INLINABLE encodeNominalDiffTime #-}
 
 encodeNonNegativeInterval :: NonNegativeInterval -> Json
diff --git a/server/test/unit/Ogmios/Data/JsonSpec.hs b/server/test/unit/Ogmios/Data/JsonSpec.hs
index fd857b2ddb..3bf41b195b 100644
--- a/server/test/unit/Ogmios/Data/JsonSpec.hs
+++ b/server/test/unit/Ogmios/Data/JsonSpec.hs
@@ -385,7 +385,7 @@ spec = do
                     \7A80D87A801A002625A0D87983D879801A000F4240D879811A000FA92E"
 
     context "SlotLength" $ do
-        let matrix = [ ( mkSlotLength 1, Json.double 1 )
+        let matrix = [ ( mkSlotLength 1, Json.integer 1 )
                      , ( mkSlotLength 0.1, Json.double 0.1 )
                      ]
         forM_ matrix $ \(slotLength, json) ->