01/01: build: emacs-build-system: Make the install phase more helpful.

[Christopher Baines]

cbaines pushed a commit to branch master
in repository guix.

commit 81fe131e0fc3c1fcfa29c140071c8cc4cff7cd2f
Author: Christopher Baines <address@hidden>
Date:   Tue Aug 22 18:11:35 2017 +0100

    build: emacs-build-system: Make the install phase more helpful.
    
    Modify the install phase to detect when nothing has been installed, and 
error
    if this happens. This is preferable to continuing, and allowing the next 
phase
    to fail.
    
    Also, when nothing can be found to be installed, print out each file that 
was
    considered, along with the regular expressions that were used to include and
    exclude it.
    
    * gnu/build/emacs-build-system.scm (install-file?): Add additional error
      checking and logging.
---
 guix/build/emacs-build-system.scm | 45 ++++++++++++++++++++++++++++-----------
 1 file changed, 32 insertions(+), 13 deletions(-)

diff --git a/guix/build/emacs-build-system.scm 
b/guix/build/emacs-build-system.scm
index bda699d..202ce53 100644
--- a/guix/build/emacs-build-system.scm
+++ b/guix/build/emacs-build-system.scm
@@ -110,22 +110,41 @@ store in '.el' files."
 
   (define source (getcwd))
 
-  (define (install-file? file stat)
-    (let ((stripped-file (string-trim (string-drop file (string-length 
source)) #\/)))
-      (and (any (cut string-match <> stripped-file) include)
-           (not (any (cut string-match <> stripped-file) exclude)))))
+  (define* (install-file? file stat #:key verbose?)
+    (let* ((stripped-file (string-trim
+                           (string-drop file (string-length source)) #\/)))
+      (define (match-stripped-file action regex)
+        (let ((result (string-match regex stripped-file)))
+          (when (and result verbose?)
+                (format #t "info: ~A ~A as it matches \"~A\"\n"
+                        stripped-file action regex))
+          result))
+
+      (when verbose?
+            (format #t "info: considering installing ~A\n" stripped-file))
+
+      (and (any (cut match-stripped-file "included" <>) include)
+           (not (any (cut match-stripped-file "excluded" <>) exclude)))))
 
   (let* ((out (assoc-ref outputs "out"))
          (elpa-name-ver (store-directory->elpa-name-version out))
-         (target-directory (string-append out %install-suffix "/" 
elpa-name-ver)))
-    (for-each
-     (lambda (file)
-       (let* ((stripped-file (string-drop file (string-length source)))
-              (target-file (string-append target-directory stripped-file)))
-         (format #t "`~a' -> `~a'~%" file target-file)
-         (install-file file (dirname target-file))))
-     (find-files source install-file?)))
-  #t)
+         (target-directory (string-append out %install-suffix "/" 
elpa-name-ver))
+         (files-to-install (find-files source install-file?)))
+    (cond
+     (files-to-install
+      (for-each
+       (lambda (file)
+         (let* ((stripped-file (string-drop file (string-length source)))
+                (target-file (string-append target-directory stripped-file)))
+           (format #t "`~a' -> `~a'~%" file target-file)
+           (install-file file (dirname target-file))))
+       files-to-install)
+      #t)
+     (else
+      (format #t "error: No files found to install.\n")
+      (find-files source (lambda (file stat)
+                           (install-file? file stat #:verbose? #t)))
+      #f))))
 
 (define* (move-doc #:key outputs #:allow-other-keys)
   "Move info files from the ELPA package directory to the info directory."