guix: scripts: Parse $GUIX_BUILD_OPTIONS separately.

Appending to "raw" args broke optional parameters in 'guix package -I'
and 'guix package -A', and possibly other places.  Therefore, switch to
parsing each set of options on its own and append resulting alists
together afterwards.

* guix/scripts/archive.scm (parse-options-from): Rename from
  (parse-options) and add explicit argument.  New form of (parse-options)
  using its old algorithm via -from function.
* guix/scripts/build.scm: Ditto.
* guix/scripts/environment.scm: Ditto.
* guix/scripts/package.scm: Ditto.
* guix/scripts/system.scm: Ditto.
* tests/guix-package.sh: Add test.
* doc/guix.texi (Invoking guix build): Make it clear that the options
  are parsed independently.

Co-authored-by: Ludovic Courtès <ludo@gnu.org>

doc/guix.texi

@@ -2802,7 +2802,8 @@ below:
 $ export GUIX_BUILD_OPTIONS="--no-substitutes -c 2 -L /foo/bar"
 @end example
 
-These options are appended to the ones passed on the command line.
+These options are parsed independently, and the result is appended to
+the parsed command-line options.
 @end defvr
 
 

guix/scripts/archive.scm

@@ -293,8 +293,12 @@ the input port."
 (define (guix-archive . args)
   (define (parse-options)
     ;; Return the alist of option values.
-    (args-fold* (append args (environment-build-options))
-                %options
+    (append (parse-options-from args)
+            (parse-options-from (environment-build-options))))
+
+  (define (parse-options-from args)
+    ;; Actual parsing takes place here.
+    (args-fold* args %options
                 (lambda (opt name arg result)
                   (leave (_ "~A: unrecognized option~%") name))
                 (lambda (arg result)

guix/scripts/build.scm

@@ -401,8 +401,12 @@ arguments with packages that use the specified source."
 (define (guix-build . args)
   (define (parse-options)
     ;; Return the alist of option values.
-    (args-fold* (append args (environment-build-options))
-                %options
+    (append (parse-options-from args)
+            (parse-options-from (environment-build-options))))
+
+  (define (parse-options-from args)
+    ;; Actual parsing takes place here.
+    (args-fold* args %options
                 (lambda (opt name arg result)
                   (leave (_ "~A: unrecognized option~%") name))
                 (lambda (arg result)

guix/scripts/environment.scm

@@ -213,8 +213,13 @@ packages."
 ;; Entry point.
 (define (guix-environment . args)
   (define (parse-options)
-    (args-fold* (append args (environment-build-options))
-                %options
+    ;; Return the alist of option values.
+    (append (parse-options-from args)
+            (parse-options-from (environment-build-options))))
+
+  (define (parse-options-from args)
+    ;; Actual parsing takes place here.
+    (args-fold* args %options
                 (lambda (opt name arg result)
                   (leave (_ "~A: unrecognized option~%") name))
                 (lambda (arg result)

guix/scripts/package.scm

@@ -668,8 +668,12 @@ removed from MANIFEST."
 (define (guix-package . args)
   (define (parse-options)
     ;; Return the alist of option values.
-    (args-fold* (append args (environment-build-options))
-                %options
+    (append (parse-options-from args)
+            (parse-options-from (environment-build-options))))
+
+  (define (parse-options-from args)
+    ;; Actual parsing takes place here.
+    (args-fold* args %options
                 (lambda (opt name arg result arg-handler)
                   (leave (_ "~A: unrecognized option~%") name))
                 (lambda (arg result arg-handler)

guix/scripts/system.scm

@@ -477,8 +477,12 @@ Build the operating system declared in FILE according to ACTION.\n"))
 (define (guix-system . args)
   (define (parse-options)
     ;; Return the alist of option values.
-    (args-fold* (append args (environment-build-options))
-                %options
+    (append (parse-options-from args)
+            (parse-options-from (environment-build-options))))
+
+  (define (parse-options-from args)
+    ;; Actual parsing takes place here.
+    (args-fold* args %options
                 (lambda (opt name arg result)
                   (leave (_ "~A: unrecognized option~%") name))
                 (lambda (arg result)

tests/guix-package.sh

@@ -289,3 +289,16 @@ GUIX_PACKAGE_PATH="$module_dir"
 export GUIX_PACKAGE_PATH
 guix package -A emacs-foo-bar | grep 42
 guix package -i emacs-foo-bar-42 -n
+unset GUIX_PACKAGE_PATH
+
+# Using 'GUIX_BUILD_OPTIONS'.
+
+available="`guix package -A | sort`"
+GUIX_BUILD_OPTIONS="--dry-run"
+export GUIX_BUILD_OPTIONS
+
+# Make sure $GUIX_BUILD_OPTIONS is not simply appended to the command-line,
+# which would break 'guix package -A' and similar.
+available2="`guix package -A | sort`"
+test "$available2" = "$available"
+guix package -I