gexp: 'gexp->script' does not emit load-path expression when unnecessary.

This removes two elements from %LOAD-PATH and %LOAD-COMPILED-PATH of the
'guix' command and thus further reduces the number of 'stat' calls it
makes.

* guix/gexp.scm (load-path-expression): Return #f when MODULES and
EXTENSIONS are both empty.
(gexp->script): Don't emit anything when SET-LOAD-PATH is #f.
This commit is contained in:
Ludovic Courtès 2019-01-07 23:45:15 +01:00
parent 49c35bbb71
commit efff32452a
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GPG key ID: 090B11993D9AEBB5

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@ -1315,7 +1315,10 @@ (define* (load-path-expression modules #:optional (path %load-path)
#:key (extensions '()))
"Return as a monadic value a gexp that sets '%load-path' and
'%load-compiled-path' to point to MODULES, a list of module names. MODULES
are searched for in PATH."
are searched for in PATH. Return #f when MODULES and EXTENSIONS are empty."
(if (and (null? modules) (null? extensions))
(with-monad %store-monad
(return #f))
(mlet %store-monad ((modules (imported-modules modules
#:module-path path))
(compiled (compiled-modules modules
@ -1338,7 +1341,7 @@ (define* (load-path-expression modules #:optional (path %load-path)
(effective-version)
"/site-ccache"))
'((ungexp-native-splicing extensions)))
%load-compiled-path))))))))
%load-compiled-path)))))))))
(define* (gexp->script name exp
#:key (guile (default-guile))
@ -1362,7 +1365,11 @@ (define* (gexp->script name exp
"#!~a/bin/guile --no-auto-compile~%!#~%"
(ungexp guile))
(write '(ungexp set-load-path) port)
(ungexp-splicing
(if set-load-path
(gexp ((write '(ungexp set-load-path) port)))
(gexp ())))
(write '(ungexp exp) port)
(chmod port #o555))))
#:module-path module-path)))