Subject: Re: bug#19219: Package names with digits following dashes

From: Mathieu Lirzin <[email-masked]>
Date: Mon, 21 Dec 2015 19:27:23 +0100

[email-masked] (Ludovic Courtès) writes:

> Mathieu Lirzin <[email-masked]> skribis:
>
>> I had the same issue when trying to create a package named
>> 'rxvt-unicode-256-color'.  I have tried to fix
>> ‘package-name->name+version’ by matching the last hyphen and check if
>> the next character is a number.
>
> Sounds like a reasonable approach (better than what I submitted), but we
> would need test for the various corner cases.  Could you augment the
> test that’s in tests/utils.scm?

The test case contains the example "guile-2.0.6.65-134c9" which
invalidates my proposal.  Here is another idea which identifies the
version part by the presence of dots.  WDYT?

--
Mathieu Lirzin

>From 19d37ea3843d236a3e32127a724a712dba3c58db Mon Sep 17 00:00:00 2001
From: Mathieu Lirzin <[email-masked]>
Date: Mon, 7 Dec 2015 05:20:08 +0100
Subject: [PATCH] utils: Improve 'package-name->name+version' version
 detection.

Fixes <http://bugs.gnu.org/19219>.

* guix/build/utils.scm (package-name->name+version): Use a more generic
heuristic to detect version.  Usage of digits in names is now possible.
* tests/utils.scm ("package-name->name+version"): Add some cases.
---
 guix/build/utils.scm | 29 +++++++++++++++--------------
 tests/utils.scm      |  6 +++++-
 2 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/guix/build/utils.scm b/guix/build/utils.scm
index e3f9edc..0ace2c7 100644
--- a/guix/build/utils.scm
+++ b/guix/build/utils.scm
@@ -100,25 +100,26 @@ is typically a \"PACKAGE-VERSION\" string."
                (+ 34 (string-length (%store-directory)))))
 
 (define (package-name->name+version name)
-  "Given NAME, a package name like \"foo-0.9.1b\", return two values:
-\"foo\" and \"0.9.1b\".  When the version part is unavailable, NAME and
-#f are returned.  The first hyphen followed by a digit is considered to
-introduce the version part."
+  "Given NAME, a package name like \"foo-0.9.1b\", return two values: \"foo\"
+and \"0.9.1b\".  When the version part is unavailable, NAME and #f are
+returned.  The version part must contain a dot to be properly detected."
   ;; See also `DrvName' in Nix.
 
   (define number?
     (cut char-set-contains? char-set:digit <>))
 
-  (let loop ((chars   (string->list name))
-             (prefix '()))
-    (match chars
-      (()
-       (values name #f))
-      ((#\- (? number? n) rest ...)
-       (values (list->string (reverse prefix))
-               (list->string (cons n rest))))
-      ((head tail ...)
-       (loop tail (cons head prefix))))))
+  (let ((lst (reverse (string->list name))))
+    (let loop ((chars lst) (suffix '()) (retry #t) (dots #f))
+      (match chars
+        (()
+         (values name #f))
+        ((#\- rest ...)
+         (cond (dots  (values (list->string (reverse rest))
+                              (list->string suffix)))
+               (retry (loop rest (cons #\- suffix) #f #f))
+               (else  (values name #f))))
+        ((head tail ...)
+         (loop tail (cons head suffix) retry (or dots (char=? #\. head))))))))
 
 (define parallel-job-count
   ;; Number of processes to be passed next to GNU Make's `-j' argument.
diff --git a/tests/utils.scm b/tests/utils.scm
index 04a859f..a7d8900 100644
--- a/tests/utils.scm
+++ b/tests/utils.scm
@@ -68,7 +68,11 @@
          '(("foo" "0.9.1b")
            ("foo-bar" "1.0")
            ("foo-bar2" #f)
-           ("guile" "2.0.6.65-134c9") ; as produced by `git-version-gen'
+           ("emacs" "24.5")
+           ("font-adobe-100-dpi" #f)
+           ("rxvt-unicode-256-color" "9.21")
+           ("guile" "2.0.6.65-134c9") ;as produced by Gnulib 'git-version-gen'
+           ("guile" "2.1.1.75-a147")  ;and with a different hash
            ("nixpkgs" "1.0pre22125_a28fe19")
            ("gtk2" "2.38.0"))))
 
-- 
2.6.3