From efb13007cd17629da9e1100854f61cbeabefb459 Mon Sep 17 00:00:00 2001
From: Matt Birkholz <matt@birchwood-abbey.net>
Date: Sun, 5 Nov 2017 16:34:10 -0700
Subject: [PATCH] Do not install an empty plugins.scm during an upgrade.

Create it when the first plugin is installed and remove it only when
removing (not upgrading!) the core package.
---
 debian/mit-scheme-pucked.prerm | 16 ++++++++++++++++
 src/Makefile.in                |  4 ----
 src/ffi/build.scm              | 19 ++++++++++++++++---
 3 files changed, 32 insertions(+), 7 deletions(-)
 create mode 100755 debian/mit-scheme-pucked.prerm

diff --git a/debian/mit-scheme-pucked.prerm b/debian/mit-scheme-pucked.prerm
new file mode 100755
index 000000000..5ea7bc6d3
--- /dev/null
+++ b/debian/mit-scheme-pucked.prerm
@@ -0,0 +1,16 @@
+#!/bin/sh
+
+set -e
+
+case "$1" in
+  remove)
+    ( echo "(parameterize ((param:suppress-loading-message? #t))"
+      echo "  (load-option 'ffi)"
+      echo "  ((access delete-plugin-list (->environment '(ffi build)))))" ) \
+    | /usr/bin/mit-scheme-pucked --batch-mode
+  ;;
+esac
+
+#DEBHELPER#
+
+exit 0
diff --git a/src/Makefile.in b/src/Makefile.in
index 894c18d1f..cd00e7fc8 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -795,10 +795,6 @@ install-auxdir-top:
 	    $(INSTALL_DATA) $(top_srcdir)/etc/optiondb.scm \
 			    $(DESTDIR)$(AUXDIR)/.; \
 	 else echo "$(DESTDIR)$(AUXDIR)/optiondb.scm already exists"; fi
-	@if ! test -e $(DESTDIR)$(AUXDIR)/plugins.scm; then \
-	    $(INSTALL_DATA) $(top_srcdir)/etc/plugins.scm \
-			    $(DESTDIR)$(AUXDIR)/.; \
-	 else echo "$(DESTDIR)$(AUXDIR)/plugins.scm already exists"; fi
 	$(INSTALL_DATA) lib/*.com $(DESTDIR)$(AUXDIR)/.
 
 .PHONY: default-target all all-native all-liarc macosx-app
diff --git a/src/ffi/build.scm b/src/ffi/build.scm
index a0662e94f..a4c1ab002 100644
--- a/src/ffi/build.scm
+++ b/src/ffi/build.scm
@@ -60,9 +60,22 @@ USA.
 		    new))
 		 (else
 		  (error "Unexpected plugin-list operation:" operation)))))
-	(begin
-	  (warn "plugin list not found:" filename)
-	  '()))))
+	(cond ((eq? operation 'add)
+	       (let ((new (list plugin)))
+		 (call-with-exclusive-output-file
+		  filename
+		  (lambda (out) (write new out)))
+		 new))
+	      ((eq? operation 'remove)
+	       (warn "plugin list not found:" filename)
+	       '())
+	      (else
+	       (error "Unexpected plugin-list operation:" operation))))))
+
+(define (delete-plugin-list)
+  (let ((path (merge-pathnames "plugins.scm"
+			       (system-library-directory-pathname))))
+    (if (file-exists? path) (delete-file path))))
 
 (define (update-optiondb plugins scmlibdir)
   (let ((filename (string scmlibdir"optiondb.scm")))
-- 
2.25.1