DEP14 policy for two dots

[Ian Jackson]

Raphael Hertzog writes ("Re: DEP14 policy for two dots"):
> Ok, can you prepare a patch for DEP-14 then? I'll apply it as it looks like
> a reasonable extension.

Attached.  FYI I intend to implement this in dgit.

Thanks,
Ian.

>From 5c63400e9be8cb1532515764a1179730aed550fb Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson at chiark.greenend.org.uk>
Date: Wed, 9 Nov 2016 18:36:23 +0000
Subject: [PATCH] DEP-14: Version -> refname mangling: Escape dots

Signed-off-by: Ian Jackson <ijackson at chiark.greenend.org.uk>
---
 deps/dep14.mdwn | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/deps/dep14.mdwn b/deps/dep14.mdwn
index 4c7ce63..a7328a4 100644
--- a/deps/dep14.mdwn
+++ b/deps/dep14.mdwn
@@ -3,7 +3,7 @@
     Title: Recommended layout for Git packaging repositories
     DEP: 14
     State: DRAFT
-    Date: 2014-11-04
+    Date: 2016-11-09
     Drivers: Raphael Hertzog <hertzog at debian.org>
     URL: http://dep.debian.net/deps/dep14
     Source: http://anonscm.debian.org/viewvc/dep/web/deps/dep14.mdwn
@@ -60,8 +60,26 @@ Version mangling
 
 When a Git tag needs to refer to a specific version of a Debian package,
 the Debian version needs to be mangled to cope with Git's restrictions.
-The colon (`:`) needs to be replaced with a percent (`%`), and the tilde
-(`~`) needs to be replaced with an underscore (`_`).
+This mangling is deterministic and reversible:
+
+ * Each colon (`:`) is replaced with a percent (`%`)
+ * Each tilde (`~`) is replaced with an underscore (`_`)
+ * A hash (`#`) is inserted between each pair of adjacent dots (`..`)
+ * A hash (`#`) is appended if the last character is a dot (`.`)
+ * If the version ends in precisely `.lock`
+   (dot `l` `o` `c` `k`, lowercase, at the end of the version),
+   a hash (`#`) is inserted after the dot, giving `.#lock`.
+
+This can be expressed concisely in the following Perl5 statements:
+
+     y/:~/%_/;
+     s/\.(?=\.|$|lock$)/.#/g;
+
+The reverse transformation is:
+
+ * Each percent (`%`) is replaced with a colon (`:`)
+ * Each underscore (`_`) is replaced with a tilde (`~`)
+ * Each hash (`#`) is deleted
 
 Packaging branches and tags
 ===========================
@@ -274,3 +292,4 @@ Changes
 =======
 
 * 2014-11-05: Initial draft by Raphaël Hertzog.
+* 2016-11-09: Extended version mangling to troublesome dots - Ian Jackson.
-- 
2.10.2



-- 
Ian Jackson <ijackson at chiark.greenend.org.uk>   These opinions are my own.

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