BigInt printf fixes

Relative and octal printing used incorrect arguments. Fixes JuliaLang#36031.

stdlib/Printf/src/Printf.jl

@@ -942,10 +942,9 @@ function decode_0ct(x::BigInt, digits)
  pt = Base.ndigits0z(x, 8) + 1
  length(digits) < pt+1 && resize!(digits, pt+1)
  neg && (x.size = -x.size)
- p = convert(Ptr{UInt8}, digits) + 1
- GMP.MPZ.get_str!(p, 8, x)
+ GMP.MPZ.get_str!(pointer(digits, 2), 8, x)
  neg && (x.size = -x.size)
- return neg, Int32(pt), Int32(pt)
+ return Int32(pt), Int32(pt), neg
 end
 
 ### decoding functions directly used by printf generated code ###
@@ -1059,13 +1058,15 @@ function ini_dec(x::BigInt, n::Int, digits)
  end
  d = Base.ndigits0z(x)
  if d <= n
- info = decode_dec(x)
- d == n && return info
- p = convert(Ptr{Cvoid}, digits) + info[2]
- ccall(:memset, Ptr{Cvoid}, (Ptr{Cvoid}, Cint, Csize_t), p, '0', n - info[2])
- return info
+ len,pt,neg = decode_dec(x, digits)
+ if d < n
+ ccall(:memset, Ptr{Cvoid}, (Ptr{Cvoid}, Cint, Csize_t), pointer(digits, pt+1), '0', n - pt)
+ end
+ return (len,pt,neg)
+ else
+ _,_,neg = decode_dec(round(BigInt,x/big(10)^(d-n)), digits)
+ return (n, d, neg)
  end
- return (n, d, decode_dec(round(BigInt,x/big(10)^(d-n)))[3])
 end
 
 

stdlib/Printf/test/runtests.jl

@@ -39,11 +39,10 @@ for (fmt, val) in (("%i", "42"),
  ("%20a"," 0x2.ap+4"),
  ("%-20a","0x2.ap+4 "),
  ("%f", "42.000000"),
- ("%g", "42")),
+ ("%g", "42"),
+ ("%e", "4.200000e+01")),
  num in (UInt16(42), UInt32(42), UInt64(42), UInt128(42),
  Int16(42), Int32(42), Int64(42), Int128(42), big"42")
- #big"42" causes stack overflow on %a ; gh #14409
- num isa BigInt && fmt in ["%a", "%#o", "%g"] && continue
  @test @eval(@sprintf($fmt, $num) == $val)
 end