From 951261e4e60a02bdfe8c0313bb03634bf02507e8 Mon Sep 17 00:00:00 2001
From: piegames <git@piegames.de>
Date: Wed, 29 Nov 2023 21:01:02 +0100
Subject: [PATCH] Strings: Fix single-line strings with double single quotes

---
 src/Nixfmt/Pretty.hs              | 6 +++++-
 test/diff/idioms_nixos_2/out.nix  | 5 +++--
 test/diff/string_interpol/out.nix | 6 ++----
 3 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/src/Nixfmt/Pretty.hs b/src/Nixfmt/Pretty.hs
index 9150255c..a38a4806 100644
--- a/src/Nixfmt/Pretty.hs
+++ b/src/Nixfmt/Pretty.hs
@@ -702,7 +702,11 @@ prettySimpleString parts = group $
 
 prettyIndentedString :: [[StringPart]] -> Doc
 prettyIndentedString parts = group $ base $
-    text "''" <> line'
+    text "''"
+    -- Usually the `''` is followed by a potential line break.
+    -- However, for single-line strings it should be omitted, because often times a line break will
+    -- not reduce the indentation at all
+    <> (case parts of { _:_:_ -> line'; _ -> mempty })
     <> nest 2 (sepBy newline (map (prettyLine escape unescapeInterpol) parts))
     <> text "''"
     where escape = replaceMultiple
diff --git a/test/diff/idioms_nixos_2/out.nix b/test/diff/idioms_nixos_2/out.nix
index d54c2fc9..79aeb15c 100644
--- a/test/diff/idioms_nixos_2/out.nix
+++ b/test/diff/idioms_nixos_2/out.nix
@@ -998,8 +998,9 @@ in
                       # will be omitted.
                       ${if c.dbname != null then "--database-name" else null} = ''"${c.dbname}"'';
                       ${if c.dbhost != null then "--database-host" else null} = ''"${c.dbhost}"'';
-                      ${if c.dbport != null then "--database-port" else null} = ''
-                        "${toString c.dbport}"'';
+                      ${
+                        if c.dbport != null then "--database-port" else null
+                      } = ''"${toString c.dbport}"'';
                       ${if c.dbuser != null then "--database-user" else null} = ''"${c.dbuser}"'';
                       "--database-pass" = ''"''$${dbpass.arg}"'';
                       "--admin-user" = ''"${c.adminuser}"'';
diff --git a/test/diff/string_interpol/out.nix b/test/diff/string_interpol/out.nix
index 50e89762..27605563 100644
--- a/test/diff/string_interpol/out.nix
+++ b/test/diff/string_interpol/out.nix
@@ -27,8 +27,7 @@
               map
                 (
                   e:
-                  ''
-                    iifname "${cfg.upstreamIface}" tcp dport ${builtins.toString e.sourcePort} dnat to ${e.destination}''
+                  ''iifname "${cfg.upstreamIface}" tcp dport ${builtins.toString e.sourcePort} dnat to ${e.destination}''
                 )
                 tcpPortMap
             )
@@ -39,8 +38,7 @@
               map
                 (
                   e:
-                  ''
-                    ifname "${cfg.upstreamIface}" udp dport ${builtins.toString e.sourcePort} dnat to ${e.destination}''
+                  ''ifname "${cfg.upstreamIface}" udp dport ${builtins.toString e.sourcePort} dnat to ${e.destination}''
                 )
                 udpPortMap
             )