From c156f4ad95c2053ebcd2e6ced9d37ce5af8cc470 Mon Sep 17 00:00:00 2001
From: Mathis Beer <Mathis.Beer@funkwerk-itk.com>
Date: Wed, 19 Sep 2018 15:50:54 +0200
Subject: [PATCH] Fix issue 19252: avoid ridiculous format length overestimate;
 dynamic-width strings should estimate width 0, not int.max

---
 std/format.d | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/std/format.d b/std/format.d
index 089cd634f..62414a169 100644
--- a/std/format.d
+++ b/std/format.d
@@ -6321,8 +6321,11 @@ private size_t guessLength(Char, S)(S fmtString)
 
         if (spec.width == spec.precision)
             len += spec.width;
-        else if (spec.width > 0 && (spec.precision == spec.UNSPECIFIED || spec.width > spec.precision))
+        else if (spec.width > 0 && spec.width != spec.DYNAMIC &&
+                 (spec.precision == spec.UNSPECIFIED || spec.width > spec.precision))
+        {
             len += spec.width;
+        }
         else if (spec.precision != spec.UNSPECIFIED && spec.precision > spec.width)
             len += spec.precision;
     }
@@ -6345,6 +6348,7 @@ unittest
     assert(guessLength!char("%2.4f") == 4);
     assert(guessLength!char("%02d:%02d:%02d") == 8);
     assert(guessLength!char("%0.2f") == 7);
+    assert(guessLength!char("%0*d") == 0);
 }
 
 /// ditto