DebianGitRepository: simplify version mangling

'%' is not valid in a Debian version number and we only want single
character replacements for now.

2 files changed, 16 insertions, 11 deletions

diff --git a/docs/chapters/import.sgml b/docs/chapters/import.sgml
index 89d15b83..c42279c9 100644
--- a/docs/chapters/import.sgml
+++ b/docs/chapters/import.sgml
@@ -274,8 +274,9 @@ upstream-tag = v%(version)s
 	  numbers by dots but rather by
 	  underscore(<replaceable>_</replaceable>),
 	  hyphen(<replaceable>-</replaceable>) or anything else. In
-	  order to cope with that you can use version mangling via
-	  substitution. The substitution works as follows:
+	  order to cope with that you can use version mangling of these
+	  characters via substitution. The substitution works as
+	  follows:
 	</para>
 <programlisting>
 [buildpackage]
@@ -292,9 +293,10 @@ upstream-tag = v%(version%.%_)s
 	  &gbp-buildpackage;.
 	</para>
 	<para>
-	  If you need to use the <replaceable>%</replaceable> character in either of the substitution strings,
+	  If you want the substitution to be the <replaceable>%</replaceable> character
 	  you have to escape it. E.g. <replaceable>%(version%-%\%)s</replaceable> will replace <replaceable>-</replaceable> with
 	  <replaceable>%</replaceable>, transforming <replaceable>1-A.B.C</replaceable> to <replaceable>1%A.B.C</replaceable>.
+	  Only a single replacement is supported and it can only replace a single character.
 	</para>
 
 	<para>If you're using &pristine-tar;, you can make &gbp-buildpackage; commit the generated tarball back to the
diff --git a/gbp/deb/git.py b/gbp/deb/git.py
index 80fb23b7..fea919d9 100644
--- a/gbp/deb/git.py
+++ b/gbp/deb/git.py
@@ -27,6 +27,11 @@ import gbp.log
 class DebianGitRepository(GitRepository):
     """A git repository that holds the source of a Debian package"""
 
+    version_mangle_re = (r'%\(version'
+                         '%(?P<M>[^%])'
+                         '%(?P<R>([^%]|\\%))+'
+                         '\)s')
+
     def __init__(self, path):
         super(DebianGitRepository, self).__init__(path)
         self.pristine_tar = DebianPristineTar(self)
@@ -132,8 +137,8 @@ class DebianGitRepository(GitRepository):
         version = version.replace('~', '.')
         return format % dict(version=version)
 
-    @staticmethod
-    def version_to_tag(format, version):
+    @classmethod
+    def version_to_tag(cls, format, version):
         """Generate a tag from a given format and a version
 
         %(version)s provides a clean version that works as a git tag.
@@ -144,7 +149,7 @@ class DebianGitRepository(GitRepository):
 
         %(version%A%B)s provides %(version)s with string 'A' replaced by 'B'.
         This way, simple version mangling is possible via substitution.
-        Inside either substition string, '%' needs to be escaped. See the
+        Inside the substition string, '%' needs to be escaped. See the
         examples below.
 
         >>> DebianGitRepository.version_to_tag("debian/%(version)s", "0:0~0")
@@ -155,13 +160,11 @@ class DebianGitRepository(GitRepository):
         'v1_2_3'
         >>> DebianGitRepository.version_to_tag("%(version%-%\%)s", "0-1.2.3")
         '0%1.2.3'
-        >>> DebianGitRepository.version_to_tag("%(version%\%%.)s", "0%1%2%3")
-        '0.1.2.3'
         """
-        r = re.search(r"%\(version%([^%]+|.*\\%.*)%([^%]+|.*\\%.*)\)s", format)
+        r = re.search(cls.version_mangle_re, format)
         if r:
-            format = re.sub(r"%\(version%([^%]+|.*\\%.*)%([^%]|.*\\%.*)+\)s", "%(version)s", format)
-            version = version.replace(r.group(1).replace('\%', '%'), r.group(2).replace('\%', '%'))
+            format = re.sub(cls.version_mangle_re, "%(version)s", format)
+            version = version.replace(r.group('M'), r.group('R').replace('\%', '%'))
         return format_str(format, dict(version=DebianGitRepository._sanitize_version(version),
                                        hversion=DebianGitRepository._sanitize_version(version).replace('.', '-')))