From 15ff89cec14ea6d1bc05a5975dedfcb6e712720b Mon Sep 17 00:00:00 2001
From: Miran <narimiran@disroot.org>
Date: Tue, 25 Aug 2020 09:57:15 +0200
Subject: [PATCH] [backport] fix #15064, strscans.scanf edge case for '$+'
 (#15223)

---
 lib/pure/strscans.nim      |  2 +-
 tests/stdlib/tstrscans.nim | 16 +++++++++++++++-
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/lib/pure/strscans.nim b/lib/pure/strscans.nim
index 0125a19266..f078b0d207 100644
--- a/lib/pure/strscans.nim
+++ b/lib/pure/strscans.nim
@@ -396,7 +396,7 @@ macro scanf*(input: string; pattern: static[string]; results: varargs[typed]): b
           var resLen = genSym(nskLet, "resLen")
           conds.add newLetStmt(resLen, newCall(bindSym"parseUntil", inp,
               results[i], newLit(token), idx))
-          conds.add newCall(bindSym"!=", resLen, newLit min)
+          conds.add newCall(bindSym">=", resLen, newLit min)
           conds.add resLen
         else:
           matchError
diff --git a/tests/stdlib/tstrscans.nim b/tests/stdlib/tstrscans.nim
index 08fc14e455..6f952368c9 100644
--- a/tests/stdlib/tstrscans.nim
+++ b/tests/stdlib/tstrscans.nim
@@ -79,8 +79,22 @@ block EmptyTuple:
 block Arrow:
   let text = "foo;bar;baz;"
   var idx = 0
-  var res = ""
   doAssert scanp(text, idx, +(~{';','\0'} -> (discard $_)), ';')
   doAssert scanp(text, idx, +(~{';','\0'} -> (discard $_)), ';')
   doAssert scanp(text, idx, +(~{';','\0'} -> (discard $_)), ';')
   doAssert scanp(text, idx, +(~{';','\0'} -> (discard $_)), ';') == false
+
+
+block issue15064:
+  var nick1, msg1: string
+  doAssert scanf("<abcd> a", "<$+> $+", nick1, msg1)
+  doAssert nick1 == "abcd"
+  doAssert msg1 == "a"
+
+  var nick2, msg2: string
+  doAssert(not scanf("<abcd> ", "<$+> $+", nick2, msg2))
+
+  var nick3, msg3: string
+  doAssert scanf("<abcd> ", "<$+> $*", nick3, msg3)
+  doAssert nick3 == "abcd"
+  doAssert msg3 == ""