Run shellcheck on cask utils and shim scripts.

Library/Homebrew/shims/linux/super/make

@@ -7,7 +7,7 @@ pathremove() {
                   NEWPATH=${NEWPATH:+$NEWPATH:}$DIR
                 fi
         done
-        export $PATHVARIABLE="$NEWPATH"
+        export "$PATHVARIABLE"="$NEWPATH"
 }
 
 if [[ -n "$HOMEBREW_MAKE" && "$HOMEBREW_MAKE" != "make" ]]
@@ -16,7 +16,8 @@ then
 else
   SAVED_PATH="$PATH"
   pathremove "$HOMEBREW_LIBRARY/Homebrew/shims/linux/super"
-  export MAKE="$(which make)"
+  MAKE="$(which make)"
+  export MAKE
   export PATH="$SAVED_PATH"
 fi
 

Library/Homebrew/shims/mac/super/ruby

@@ -1,6 +1,9 @@
 #!/bin/bash
+
 # System Ruby's mkmf on Mojave (10.14) and later require SDKROOT set to work correctly.
 
+# Don't need shellcheck to follow the `source`.
+# shellcheck disable=SC1090
 source "$HOMEBREW_LIBRARY/Homebrew/shims/utils.sh"
 
 try_exec_non_system "$SHIM_FILE" "$@"

Library/Homebrew/shims/mac/super/xcrun

@@ -1,4 +1,5 @@
 #!/bin/bash
+
 # Historically, xcrun has had various bugs, and in some cases it didn't
 # work at all (e.g. CLT-only in the Xcode 4.3 era). This script emulates
 # it and attempts to avoid these issues.
@@ -27,10 +28,10 @@ arg0=$1
 shift
 
 exe="/usr/bin/${arg0}"
-if [ -x "$exe" ]; then
-  if [ -n "$HOMEBREW_PREFER_CLT_PROXIES" ]; then
+if [[ -x "$exe" ]]; then
+  if [[ -n "$HOMEBREW_PREFER_CLT_PROXIES" ]]; then
     exec "$exe" "$@"
-  elif [ -z "$HOMEBREW_SDKROOT" -o ! -d "$HOMEBREW_SDKROOT" ]; then
+  elif [[ -z "$HOMEBREW_SDKROOT" || ! -d "$HOMEBREW_SDKROOT" ]]; then
     exec "$exe" "$@"
   fi
 fi
@@ -38,7 +39,7 @@ fi
 SUPERBIN=$(cd "${0%/*}" && pwd -P)
 
 exe=$(/usr/bin/xcrun --find "$arg0" 2>/dev/null)
-if [ -x "$exe" -a "${exe%/*}" != "$SUPERBIN" ]; then
+if [[ -x "$exe" && "${exe%/*}" != "$SUPERBIN" ]]; then
   exec "$exe" "$@"
 fi
 
@@ -57,7 +58,7 @@ done
 IFS=$old_IFS
 
 echo >&2 "
-Failed to execute $arg0 $@
+Failed to execute ${arg0} ${*}
 
 Xcode and/or the CLT appear to be misconfigured. Try one or both of the following:
   xcodebuild -license

Library/Homebrew/shims/scm/git

@@ -9,6 +9,8 @@ then
   exit 1
 fi
 
+# Don't need shellcheck to follow the `source`.
+# shellcheck disable=SC1090
 source "$HOMEBREW_LIBRARY/Homebrew/shims/utils.sh"
 
 case "$(lowercase "$SHIM_FILE")" in

Library/Homebrew/shims/utils.sh

@@ -60,8 +60,10 @@ safe_exec() {
   fi
   if [[ "$HOMEBREW" = "print-path" ]]
   then
-    local dir="$(quiet_safe_cd "${arg0%/*}/" && pwd)"
-    local path="$(dirbasepath "$dir" "$arg0")"
+    local dir
+    dir="$(quiet_safe_cd "${arg0%/*}/" && pwd)"
+    local path
+    path="$(dirbasepath "$dir" "$arg0")"
     echo "$path"
     exit
   fi

Library/Homebrew/style.rb

@@ -177,13 +177,16 @@ module Homebrew
         files = [
           HOMEBREW_BREW_FILE,
           # TODO: HOMEBREW_REPOSITORY/"completions/bash/brew",
-          *Pathname.glob("#{HOMEBREW_LIBRARY}/Homebrew/*.sh"),
-          *Pathname.glob("#{HOMEBREW_LIBRARY}/Homebrew/cmd/*.sh"),
-          *Pathname.glob("#{HOMEBREW_LIBRARY}/Homebrew/utils/*.sh"),
+          *HOMEBREW_LIBRARY.glob("Homebrew/*.sh"),
+          *HOMEBREW_LIBRARY.glob("Homebrew/shims/**/*").map(&:realpath).uniq
+                           .reject { |path| path.directory? || path.basename.to_s == "cc" },
+          *HOMEBREW_LIBRARY.glob("Homebrew/{dev-,}cmd/*.sh"),
+          *HOMEBREW_LIBRARY.glob("Homebrew/{cask/,}utils/*.sh"),
         ]
       end
 
-      args = ["--shell=bash", "--", *files] # TODO: Add `--enable=all` to check for more problems.
+      # TODO: Add `--enable=all` to check for more problems.
+      args = ["--shell=bash", "--external-sources", "--", *files]
 
       case output_type
       when :print