From 61c8a2b1e7c17a1d5c88214452816b496b26f4a1 Mon Sep 17 00:00:00 2001
From: Andreas Rumpf <rumpf_a@web.de>
Date: Tue, 21 Jan 2020 16:49:59 +0100
Subject: [PATCH] fixes a critical times.nim bug reported on IRC [backport]
 (#13216)

(cherry picked from commit bdb7c82c6aaf60392285cfea43c65c5b9b919e27)
---
 lib/pure/strformat.nim | 3 +++
 lib/pure/times.nim     | 5 +++--
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/lib/pure/strformat.nim b/lib/pure/strformat.nim
index 257751088c..1233317135 100644
--- a/lib/pure/strformat.nim
+++ b/lib/pure/strformat.nim
@@ -707,6 +707,9 @@ when isMainModule:
   var tm = fromUnix(0)
   discard &"{tm}"
 
+  var noww = now()
+  check &"{noww}", $noww
+
   # Unicode string tests
   check &"""{"αβγ"}""", "αβγ"
   check &"""{"αβγ":>5}""", "  αβγ"
diff --git a/lib/pure/times.nim b/lib/pure/times.nim
index 9af39920d8..4cf8a5e988 100644
--- a/lib/pure/times.nim
+++ b/lib/pure/times.nim
@@ -2316,9 +2316,10 @@ proc format*(dt: DateTime, f: static[string]): string {.raises: [].} =
   const f2 = initTimeFormat(f)
   result = dt.format(f2)
 
-template formatValue*(result: var string; value: DateTime, specifier: string) =
+proc formatValue*(result: var string; value: DateTime, specifier: string) =
   ## adapter for strformat. Not intended to be called directly.
-  result.add format(value, specifier)
+  result.add format(value,
+    if specifier.len == 0: "yyyy-MM-dd'T'HH:mm:sszzz" else: specifier)
 
 proc format*(time: Time, f: string, zone: Timezone = local()): string
     {.raises: [TimeFormatParseError].} =