Merge tag 'debian/1.1' into jessie-bpo

dh-elpa Debian release 1.1

# gpg: Signature made Fri 12 Aug 2016 07:54:38 PM MST
# gpg:                using RSA key 0x0F56D0553B6D411B
# gpg: Good signature from "Sean Whitton <spwhitton@spwhitton.name>" [ultimate]
# Primary key fingerprint: 8DC2 487E 51AB DD90 B5C4  753F 0F56 D055 3B6D 411B

3 files changed, 61 insertions, 9 deletions

diff --git a/debian/changelog b/debian/changelog
index f15aa65..4b911d9 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,10 @@
+dh-elpa (1.1) unstable; urgency=medium
+
+  * Attempt to sanitise versions from DEB_* env vars so that Emacs accepts
+    them as ELPA package version strings.
+
+ -- Sean Whitton <spwhitton@spwhitton.name>  Fri, 12 Aug 2016 19:51:04 -0700
+
 dh-elpa (1.0~bpo8+1) UNRELEASED; urgency=medium
 
   * Rebuild for jessie-backports.
diff --git a/dh-elpa.el b/dh-elpa.el
index 6137ab2..094913e 100644
--- a/dh-elpa.el
+++ b/dh-elpa.el
@@ -108,19 +108,58 @@ DEB_VERSION_UPSTREAM environment variables are set."))
   "Return the package version as found in standard DEB_* environment variables.
 
 Try DEB_UPSTREAM_VERSION first, then DEB_VERSION_UPSTREAM.
-Signal an error if these are both set and they disagree."
+Signal an error if these are both set and they disagree.
+
+Versions taken from environment variables are run through
+`dhelpa-sanitise-version'."
   ;; If one of these environment variables is the empty string, it's
   ;; as good as unset, so we replace that with the nil value.
-  (let ((upstream-version (null-empty-string
-                           (getenv "DEB_UPSTREAM_VERSION")))
-        (version-upstream (null-empty-string
-                           (getenv "DEB_VERSION_UPSTREAM"))))
+  (let* ((upstream-version (null-empty-string
+                            (getenv "DEB_UPSTREAM_VERSION")))
+         (version-upstream (null-empty-string
+                            (getenv "DEB_VERSION_UPSTREAM")))
+         (version (if upstream-version upstream-version version-upstream))
+         (sanitised-version (dhelpa-sanitise-version version)))
+    ;; sanity check #1
     (if (and upstream-version
              version-upstream
              (not (string= upstream-version version-upstream)))
         (error "The DEB_UPSTREAM_VERSION and DEB_VERSION_UPSTREAM
 environment variables are both set, but they disagree.")
-      (if upstream-version upstream-version version-upstream))))
+      ;; sanity check #2
+      (unless (ignore-errors (version-to-list sanitised-version))
+        (error (concat "E: The Debian version " version " cannot be used as an ELPA version.
+See dh_elpa(1) HINTS for how to deal with this.")))
+      ;; if we got this far, return it
+      sanitised-version)))
+
+;;;###autoload
+(defun dhelpa-sanitise-version (version)
+  "Sanitise a Debian version VERSION such that it will work with Emacs.
+
+Our goal is to ensure that ELPA package versions are sorted
+correctly relative to other versions of the package the user
+might have installed in their home directory.
+
+To do this:
+
+- we remove all indication of backporting, since that is a matter
+  of Debian packaging and shouldn't affect the ELPA package
+  content
+
+- we replace '~' with '-' -- Emacs interprets '-rc', '-git' and
+  '-pre' similar to how dpkg interprets '~rc', '~git' and
+  '~pre' (see `version-to-list')
+
+This will not give the right answer in all cases (for example
+'~foo' where 'foo' is not one of the strings Emacs recognises as
+a pre-release).  The Debian package maintainer should patch the
+upstream source to include a proper Package-Version: header in
+such a case."
+  (when version
+    (replace-regexp-in-string
+     "~" "-"
+     (replace-regexp-in-string "~bpo.*$" "" version))))
 
 (defun null-empty-string (str)
   "If STR is a string of length zero, return nil.  Otherwise, return STR."
diff --git a/dh_elpa.in b/dh_elpa.in
index 67cd9d8..5e5828b 100755
--- a/dh_elpa.in
+++ b/dh_elpa.in
@@ -326,9 +326,10 @@ substvars
 
 If dh_elpa can't determine the package version by looking at *.el
 files (usually because upstream has failed to include the proper
-headers), it will fallback to the DEB_UPSTREAM_VERSION and
-DEB_VERSION_UPSTREAM environment variables.  An easy way to set one of
-these is just to prepend the following to your rules file:
+headers or *-pkg.el file), it will fallback to the
+DEB_UPSTREAM_VERSION and DEB_VERSION_UPSTREAM.  An easy way to set one
+of these based on your latest Debian changelog entry is just to
+prepend the following to your rules file:
 
 =over 4
 
@@ -337,3 +338,8 @@ these is just to prepend the following to your rules file:
 
 =back
 
+Certain Debian upstream version strings cannot be translated into
+version strings Emacs will accept (see the docstring for the Emacs
+function `version-to-list' for details).  dh_elpa will error out if
+the version cannot be translated.  You should resort to patching in a
+Package-Version header or adding a *-pkg.el file.