From 55afecccffe5f981443ee8b1b139133b2a7c1f81 Mon Sep 17 00:00:00 2001
From: "John M. Kuhn" <jmkuhn@users.noreply.github.com>
Date: Wed, 20 Mar 2024 18:10:23 -0400
Subject: [PATCH] Printf: don't zero pad Inf or NaN (#53785)

We currently have
```
julia> @sprintf("%07f", -Inf)
"-000Inf"

julia> @sprintf("%07f", NaN)
"0000NaN"
```

With this PR
```
julia> @sprintf("%07f", -Inf)
"   -Inf"

julia> @sprintf("%07f", NaN)
"    NaN"
```
which is the same as Julia 1.5.4 and agrees with the C standard.
---
 stdlib/Printf/src/Printf.jl    | 2 +-
 stdlib/Printf/test/runtests.jl | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/stdlib/Printf/src/Printf.jl b/stdlib/Printf/src/Printf.jl
index 860ef3610f728..9b636d1180598 100644
--- a/stdlib/Printf/src/Printf.jl
+++ b/stdlib/Printf/src/Printf.jl
@@ -654,7 +654,7 @@ const __BIG_FLOAT_MAX__ = 8192
         else
             # right aligned
             n = width - (newpos - pos)
-            if zero
+            if zero && isfinite(x)
                 ex = (arg < 0 || (plus | space)) + (T <: Union{Val{'a'}, Val{'A'}} ? 2 : 0)
                 so = pos + ex
                 len = (newpos - pos) - ex
diff --git a/stdlib/Printf/test/runtests.jl b/stdlib/Printf/test/runtests.jl
index f00d7abe362c5..abe547c00ed0d 100644
--- a/stdlib/Printf/test/runtests.jl
+++ b/stdlib/Printf/test/runtests.jl
@@ -116,12 +116,15 @@ end
     @test (Printf.@sprintf "%+f" Inf) == "+Inf"
     @test (Printf.@sprintf "% f" Inf) == " Inf"
     @test (Printf.@sprintf "% #f" Inf) == " Inf"
+    @test (Printf.@sprintf "%07f" Inf) == "    Inf"
     @test (Printf.@sprintf "%f" -Inf) == "-Inf"
     @test (Printf.@sprintf "%+f" -Inf) == "-Inf"
+    @test (Printf.@sprintf "%07f" -Inf) == "   -Inf"
     @test (Printf.@sprintf "%f" NaN) == "NaN"
     @test (Printf.@sprintf "%+f" NaN) == "+NaN"
     @test (Printf.@sprintf "% f" NaN) == " NaN"
     @test (Printf.@sprintf "% #f" NaN) == " NaN"
+    @test (Printf.@sprintf "%07f" NaN) == "    NaN"
     @test (Printf.@sprintf "%e" big"Inf") == "Inf"
     @test (Printf.@sprintf "%e" big"NaN") == "NaN"
 
@@ -169,12 +172,15 @@ end
     @test (Printf.@sprintf "%+e" Inf) == "+Inf"
     @test (Printf.@sprintf "% e" Inf) == " Inf"
     @test (Printf.@sprintf "% #e" Inf) == " Inf"
+    @test (Printf.@sprintf "%07e" Inf) == "    Inf"
     @test (Printf.@sprintf "%e" -Inf) == "-Inf"
     @test (Printf.@sprintf "%+e" -Inf) == "-Inf"
+    @test (Printf.@sprintf "%07e" -Inf) == "   -Inf"
     @test (Printf.@sprintf "%e" NaN) == "NaN"
     @test (Printf.@sprintf "%+e" NaN) == "+NaN"
     @test (Printf.@sprintf "% e" NaN) == " NaN"
     @test (Printf.@sprintf "% #e" NaN) == " NaN"
+    @test (Printf.@sprintf "%07e" NaN) == "    NaN"
     @test (Printf.@sprintf "%e" big"Inf") == "Inf"
     @test (Printf.@sprintf "%e" big"NaN") == "NaN"