diff options
Diffstat (limited to 'guix/build/union.scm')
| -rw-r--r-- | guix/build/union.scm | 29 |
1 files changed, 25 insertions, 4 deletions
diff --git a/guix/build/union.scm b/guix/build/union.scm index 275746d83e..077b7fe530 100644 --- a/guix/build/union.scm +++ b/guix/build/union.scm @@ -105,7 +105,22 @@ single leaf." the DIRECTORIES." (define (file-tree dir) ;; Return the contents of DIR as a tree. - (match (file-system-fold (const #t) + + (define (others-have-it? subdir) + ;; Return #t if other elements of DIRECTORIES have SUBDIR. + (let ((subdir (substring subdir (string-length dir)))) + (any (lambda (other) + (and (not (string=? other dir)) + (file-exists? (string-append other "/" subdir)))) + directories))) + + (match (file-system-fold (lambda (subdir stat result) ; enter? + ;; No need to traverse DIR since there's + ;; nothing to union it with. Thus, we avoid + ;; creating a gazillon symlinks (think + ;; share/emacs/24.3, share/texmf, etc.) + (or (string=? subdir dir) + (others-have-it? subdir))) (lambda (file stat result) ; leaf (match result (((siblings ...) rest ...) @@ -117,7 +132,12 @@ the DIRECTORIES." (((leaves ...) (siblings ...) rest ...) `(((,(basename dir) ,@leaves) ,@siblings) ,@rest)))) - (const #f) ; skip + (lambda (dir stat result) ; skip + ;; DIR is not available elsewhere, so treat it + ;; as a leaf. + (match result + (((siblings ...) rest ...) + `((,dir ,@siblings) ,@rest)))) (lambda (file stat errno result) (format (current-error-port) "union-build: ~a: ~a~%" file (strerror errno))) @@ -158,8 +178,9 @@ the DIRECTORIES." (mkdir output) (let loop ((tree (delete-duplicate-leaves (cons "." - (tree-union (append-map (compose tree-leaves file-tree) - directories))) + (tree-union + (append-map (compose tree-leaves file-tree) + (delete-duplicates directories)))) leaf=? resolve-collision)) (dir '())) |