nixpkgs/pkgs/build-support/emacs/wrapper.sh

#!@bash@

IFS=:

newLoadPath=()
added=

if [[ -n $EMACSLOADPATH ]]
then
    while read -rd: entry
    do
        if [[ -z $entry && -z $added ]]
        then
            newLoadPath+=(@wrapperSiteLisp@)
            added=1
        fi
        newLoadPath+=("$entry")
    done <<< "$EMACSLOADPATH:"
else
    newLoadPath+=(@wrapperSiteLisp@)
    newLoadPath+=("")
fi

export EMACSLOADPATH="${newLoadPath[*]}"
export emacsWithPackages_siteLisp=@wrapperSiteLisp@

exec @prog@ "$@"
emacsWithPackages: mutate EMACSLOADPATH correctly An empty entry in EMACSLOADPATH gets filled with the default value. This is presumably why the wrapper inserted a colon after the entry it added for the dependencies. But this naive approach wasn't always correct. For example, if the user ran emacs with EMACSLOADPATH=foo, the wrapper would insert the default value (by adding the trailing `:') even though the user was trying to expressly opt out of it. To do this correctly, here I've replaced makeWrapper with a bespoke script that will actually parse the EMACSLOADPATH provided in the environment (if given), and insert the wrapper's load path just before the default value. If EMACSLOADPATH is given but contains no default value, we respect that and don't add the wrapped dependencies at all. If no EMACSLOADPATH is given, we insert the wrapped dependencies before the default value, just like before. In this way, the wrapped Emacs should now behave as if the wrapped dependencies were part of Emacs's default load-path value. 2020-12-09 15:53:10 +00:00			`#!@bash@`

			`IFS=:`

			`newLoadPath=()`
			`added=`

			`if [[ -n $EMACSLOADPATH ]]`
			`then`
			`while read -rd: entry`
			`do`
			`if [[ -z $entry && -z $added ]]`
			`then`
			`newLoadPath+=(@wrapperSiteLisp@)`
			`added=1`
			`fi`
			`newLoadPath+=("$entry")`
			`done <<< "$EMACSLOADPATH:"`
			`else`
			`newLoadPath+=(@wrapperSiteLisp@)`
			`newLoadPath+=("")`
			`fi`

			`export EMACSLOADPATH="${newLoadPath[*]}"`
emacsWithPackages: don't tell sub-Emacs about pkgs If I'm running an Emacs executable from emacsWithPackages as my main programming environment, and I'm hacking on Emacs, or the Emacs packaging in Nixpkgs, or whatever, I don't want the Emacs packages from the wrapper to show up in the load path of that child Emacs. It results in differing behaviour depending on whether the child Emacs is run from Emacs or from, for example, an external terminal emulator, which is very surprising. To avoid this, pass another environment variable containing the wrapper site-lisp path, and use that value to remove the corresponding entry in EMACSLOADPATH, so it won't be propagated to child Emacsen. 2020-12-07 18:53:54 +00:00			`export emacsWithPackages_siteLisp=@wrapperSiteLisp@`
emacsWithPackages: mutate EMACSLOADPATH correctly An empty entry in EMACSLOADPATH gets filled with the default value. This is presumably why the wrapper inserted a colon after the entry it added for the dependencies. But this naive approach wasn't always correct. For example, if the user ran emacs with EMACSLOADPATH=foo, the wrapper would insert the default value (by adding the trailing `:') even though the user was trying to expressly opt out of it. To do this correctly, here I've replaced makeWrapper with a bespoke script that will actually parse the EMACSLOADPATH provided in the environment (if given), and insert the wrapper's load path just before the default value. If EMACSLOADPATH is given but contains no default value, we respect that and don't add the wrapped dependencies at all. If no EMACSLOADPATH is given, we insert the wrapped dependencies before the default value, just like before. In this way, the wrapped Emacs should now behave as if the wrapped dependencies were part of Emacs's default load-path value. 2020-12-09 15:53:10 +00:00
			`exec @prog@ "$@"`