Fix Date parsing crash when parsing a negative year (#53981)

Fixes #50328.
Originally checked on version 1.10.0 but still relevant in the current
version in master

Bug: In method Date(str), when given a negative year as an argument (ex:
"-2000"), it would output an error while in Date(int) once given a
negative year (ex: "-2000") it would work as intended returning
"-2000-01-01".

Fix: In function tryparsenext_base10 the character '-' wasn't being
accounted so i check if it existed in the first iteration of the string
and if yes I would multiply the output * -1.

Test: Added some tests that verify this specific Fix.

---------

Co-authored-by: Jameson Nash <[email protected]>
Co-authored-by: Viral B. Shah <[email protected]>

Author: 3 people

stdlib/Dates/src/parse.jl

@@ -161,6 +161,13 @@ end
     min_pos = min_width <= 0 ? i : i + min_width - 1
     max_pos = max_width <= 0 ? len : min(i + max_width - 1, len)
     d::Int64 = 0
+    c, neg = iterate(str, i)::Tuple{Char, Int}
+    if c == '-'
+        i = neg
+        neg = -1
+    else
+        neg = 1
+    end
     @inbounds while i <= max_pos
         c, ii = iterate(str, i)::Tuple{Char, Int}
         if '0' <= c <= '9'
@@ -173,7 +180,7 @@ end
     if i <= min_pos
         return nothing
     else
-        return d, i
+        return d * neg, i
     end
 end
 

stdlib/Dates/test/io.jl

@@ -621,4 +621,9 @@ end
     end
 end
 
+@testset "Issue #50328: parsing negative years" begin
+    @test Date("-2013-10-10") == Date(-2013, 10, 10)
+    @test Date("-2013") == Date(-2013, 01, 01)
+end
+
 end