From 2e3d95041e356e681a88cf3fecaa1aae57116c28 Mon Sep 17 00:00:00 2001
From: Joseph Wright <joseph.wright@morningstar2.co.uk>
Date: Mon, 6 Nov 2023 17:09:48 +0000
Subject: [PATCH] Fix printing "1" when "print-unity-mantissa = false"

Fixes #700.
---
 CHANGELOG.md                 | 4 ++++
 siunitx-number.dtx           | 6 +++++-
 testfiles/siunitx-number.lvt | 3 +++
 testfiles/siunitx-number.tlg | 9 +++++++++
 4 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 28388816..fa052265 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -19,6 +19,10 @@ Changelog](https://keepachangelog.com/en/1.0.0/), and this project adheres to
   - `\siunitx_declare_unit:Nx`
   - `\siunitx_declare_unit:Nxn`
 
+### Fixed
+- Printing of `1` when `print-unity-mantissa = false` (see issue
+  [\#700](https://github.com/josephwright/siunitx/issues/700))
+
 ## [v3.3.7] - 2023-10-07
 
 ### Fixed
diff --git a/siunitx-number.dtx b/siunitx-number.dtx
index 39917f81..04b302cf 100644
--- a/siunitx-number.dtx
+++ b/siunitx-number.dtx
@@ -4148,7 +4148,11 @@
                 { ! \str_if_eq_p:nn { #1 . #2 } { 1. } }
                 {
                   \bool_lazy_and_p:nn
-                    { \str_if_eq_p:nn {#3} { 0 } }
+                    {
+                      \bool_lazy_or_p:nn
+                        { \tl_if_blank_p:n {#3} }
+                        { \str_if_eq_p:nn {#3} { 0 } }
+                    }
                     { ! \l_@@_zero_exponent_bool }
                 }
                 {
diff --git a/testfiles/siunitx-number.lvt b/testfiles/siunitx-number.lvt
index 9ce5d395..3f69ef85 100644
--- a/testfiles/siunitx-number.lvt
+++ b/testfiles/siunitx-number.lvt
@@ -705,12 +705,15 @@
   {
     \test:n { 1e10 }
     \test:n { 1e0 }
+    \test:n { 1 }
     \keys_set:nn { siunitx } { print-unity-mantissa = true }
     \test:n { 1e10 }
     \test:n { 1e0 }
+    \test:n { 1 }
     \keys_set:nn { siunitx } { print-unity-mantissa = false }
     \test:n { 1e10 }
     \test:n { 1e0 }
+    \test:n { 1 }
   }
 
 \TEST { Option~setting~"print-zero-exponent" }
diff --git a/testfiles/siunitx-number.tlg b/testfiles/siunitx-number.tlg
index 77942a13..eb2c02a3 100644
--- a/testfiles/siunitx-number.tlg
+++ b/testfiles/siunitx-number.tlg
@@ -1641,18 +1641,27 @@ l. ...  }
 > \l_tmpa_tl=1.
 <recently read> }
 l. ...  }
+> \l_tmpa_tl=1.
+<recently read> }
+l. ...  }
 > \l_tmpa_tl=1\times 10^{10}.
 <recently read> }
 l. ...  }
 > \l_tmpa_tl=1.
 <recently read> }
 l. ...  }
+> \l_tmpa_tl=1.
+<recently read> }
+l. ...  }
 > \l_tmpa_tl=10^{10}.
 <recently read> }
 l. ...  }
 > \l_tmpa_tl=1.
 <recently read> }
 l. ...  }
+> \l_tmpa_tl=1.
+<recently read> }
+l. ...  }
 ============================================================
 ============================================================
 TEST 53: Option setting "print-zero-exponent"