From 58eb3d380601897c6ba9679eafc9c77305549b6f Mon Sep 17 00:00:00 2001
From: Greg Pfeil <greg@technomadic.org>
Date: Mon, 5 Dec 2022 01:16:12 -0700
Subject: [PATCH] mkshell: refactor Bash snippet
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I’ve been using https://github.com/Fuuzetsu/shellcheck-nix-attributes on most of
my derivations, and attaching it to one derived from `mkShell` resulted in

```
shellcheck_buildPhase

In /nix/store/8774inwznc87dwhac90winc9b5k6gmkb-nix-shell_shellcheck_buildPhase line 1:
echo "------------------------------------------------------------" >>$out
^-- SC2129 (style): Consider using { cmd1; cmd2; } >> file instead of individual redirects.
                                                                      ^--^ SC2086 (info): Double quote to prevent globbing and word splitting.

Did you mean:
echo "------------------------------------------------------------" >>"$out"

In /nix/store/8774inwznc87dwhac90winc9b5k6gmkb-nix-shell_shellcheck_buildPhase line 2:
echo " WARNING: the existence of this path is not guaranteed." >>$out
                                                                 ^--^ SC2086 (info): Double quote to prevent globbing and word splitting.

Did you mean:
echo " WARNING: the existence of this path is not guaranteed." >>"$out"

In /nix/store/8774inwznc87dwhac90winc9b5k6gmkb-nix-shell_shellcheck_buildPhase line 3:
echo " It is an internal implementation detail for pkgs.mkShell."   >>$out
                                                                      ^--^ SC2086 (info): Double quote to prevent globbing and word splitting.

Did you mean:
echo " It is an internal implementation detail for pkgs.mkShell."   >>"$out"

In /nix/store/8774inwznc87dwhac90winc9b5k6gmkb-nix-shell_shellcheck_buildPhase line 4:
echo "------------------------------------------------------------" >>$out
                                                                      ^--^ SC2086 (info): Double quote to prevent globbing and word splitting.

Did you mean:
echo "------------------------------------------------------------" >>"$out"

In /nix/store/8774inwznc87dwhac90winc9b5k6gmkb-nix-shell_shellcheck_buildPhase line 5:
echo >> $out
        ^--^ SC2086 (info): Double quote to prevent globbing and word splitting.

Did you mean:
echo >> "$out"

In /nix/store/8774inwznc87dwhac90winc9b5k6gmkb-nix-shell_shellcheck_buildPhase line 7:
export >> $out
          ^--^ SC2086 (info): Double quote to prevent globbing and word splitting.

Did you mean:
export >> "$out"

For more information:
  https://www.shellcheck.net/wiki/SC2086 -- Double quote to prevent globbing ...
  https://www.shellcheck.net/wiki/SC2129 -- Consider using { cmd1; cmd2; } >>...
```
——— https://garnix.io/build/qgxbameB

This addresses the shellcheck complaints.
---
 pkgs/build-support/mkshell/default.nix | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/pkgs/build-support/mkshell/default.nix b/pkgs/build-support/mkshell/default.nix
index e7552f434848..39b02a47141a 100644
--- a/pkgs/build-support/mkshell/default.nix
+++ b/pkgs/build-support/mkshell/default.nix
@@ -44,12 +44,13 @@ stdenv.mkDerivation ({
   phases = [ "buildPhase" ];
 
   buildPhase = ''
-    echo "------------------------------------------------------------" >>$out
-    echo " WARNING: the existence of this path is not guaranteed." >>$out
-    echo " It is an internal implementation detail for pkgs.mkShell."   >>$out
-    echo "------------------------------------------------------------" >>$out
-    echo >> $out
-    # Record all build inputs as runtime dependencies
-    export >> $out
+    { echo "------------------------------------------------------------";
+      echo " WARNING: the existence of this path is not guaranteed.";
+      echo " It is an internal implementation detail for pkgs.mkShell.";
+      echo "------------------------------------------------------------";
+      echo;
+      # Record all build inputs as runtime dependencies
+      export;
+    } >> "$out"
   '';
 } // rest)