gnu: icedove: Compute a self-contained source.

This refactoring work is to prepare for adding a icedove-l10n package, which
will reuse that source.

* gnu/packages/gnuzilla.scm (comm-source->locales+changset): New procedure.
(thunderbird-source): Rename to...
(thunderbird-comm-source): ... here.
(icedove-source): New variable.
(icedove) [source]: Use it.
[phases]: Remove the prepare-thunderbird-sources and rename-to-icedove phases.

gnu/packages/gnuzilla.scm

@@ -47,6 +47,7 @@ (define-module (gnu packages gnuzilla)
   #:use-module (guix hg-download)
   #:use-module (guix gexp)
   #:use-module (guix store)
+  #:use-module (guix modules)
   #:use-module (guix monads)
   #:use-module (guix utils)
   #:use-module (guix build-system gnu)
@@ -1119,7 +1120,7 @@ (define %icedove-version "102.7.2")
 
 ;; Provides the "comm" folder which is inserted into the icecat source.
 ;; Avoids the duplication of Icecat's source tarball.
-(define thunderbird-source
+(define thunderbird-comm-source
   (origin
     (method hg-fetch)
     (uri (hg-reference
@@ -1130,65 +1131,74 @@ (define thunderbird-source
      (base32
       "071q0pcfvfpzx741ly1sl8anlmzx02h17w4ylfnrkwrpaclq3p6p"))))
 
-(define-public icedove
-  (package
-    (name "icedove")
-    (version %icedove-version)
-    (source icecat-source)
-    (properties
-     `((cpe-name . "thunderbird_esr")))
-    (build-system gnu-build-system)
-    (arguments
-     (list
-      #:tests? #f                             ;no check target
-      #:imported-modules %cargo-utils-modules ;for `generate-all-checksums'
-      #:modules `((guix build utils)          ;find-files
-                  (sxml simple)
-                  (ice-9 regex)
-                  ,@%gnu-build-system-modules)
-      #:phases
-      #~(modify-phases %standard-phases
-          (add-after 'unpack 'prepare-thunderbird-sources
-            (lambda _
+(define (comm-source->locales+changeset source)
+  "Given SOURCE, a checkout of the Thunderbird 'comm' component, return the
+list of languages supported as well as the currently used changeset."
+  (match (update-mozilla-locales
+          (string-append source "/mail/locales/l10n-changesets.json"))
+    (((_ changeset locale) ...)
+     (values locale (first changeset)))))
+
+;;; To find out which changeset to use for the comm-l10n repo, use the
+;;; 'comm-source->locales+changeset' procedure on the thunderbird-comm-source
+;;; checkout directory.  The complete localization data should be released as
+;;; a tarball in the next release (see:
+;;; https://bugzilla.mozilla.org/show_bug.cgi?id=1817086).  When this tarball
+;;; is available, it should replace the complete 'l10n' directory at the root
+;;; of the IceCat source, instead of only the 'calendar', chat and mail
+;;; directories that it provides.
+(define thunderbird-comm-l10n
+  (let* ((changeset "5b6788295358")
+         (version (git-version %icedove-version "0" changeset)))
+    (origin
+      (method hg-fetch)
+      (uri (hg-reference
+            (url "https://hg.mozilla.org/projects/comm-l10n")
+            (changeset changeset)))
+      (file-name (git-file-name "comm-l10n" version))
+      (sha256
+       (base32
+        "1jrsmkscjjllcfawi3788vwm53wn25inbhdis5nk4vfpr7wk5ill")))))
+
+(define icedove-source
+  (let ((name (string-append "icedove-" %icedove-version)))
+    (origin
+      (method computed-origin-method)
+      (file-name (string-append name ".tar.xz"))
+      (sha256 #f)
+      (uri
+       (delay
+         (with-imported-modules (source-module-closure '((guix build utils)))
+           #~(begin
+               (use-modules (guix build utils)
+                            (sxml simple))
+
+               (set-path-environment-variable
+                "PATH" '("bin")
+                (list #+(canonical-package tar)
+                      #+(canonical-package xz)))
+
+               ;; Extract the base Icecat tarball, renaming its top-level
+               ;; directory.
+               (invoke "tar" "--transform" (string-append "s,[^/]*," #$name ",")
+                       "-xf" #$icecat-source)
+               (chdir #$name)
+
+               ;; Merge the Thunderdbird localization data.
+               (copy-recursively #$thunderbird-comm-l10n "l10n")
+
+               ;; Add the Thunderbird-specific "comm" directory..
                (mkdir "comm")
-              (copy-recursively #$thunderbird-source "comm")
-              (delete-file "sourcestamp.txt")))
-          (add-after 'patch-source-shebangs 'patch-cargo-checksums
-            (lambda _
-              (use-modules (guix build cargo-utils))
-              (let ((null-hash "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934\
-ca495991b7852b855"))
-                (for-each (lambda (file)
-                            (format #t "patching checksums in ~a~%" file)
-                            (substitute* file
-                              (("^checksum = \".*\"")
-                               (string-append "checksum = \"" null-hash "\""))))
-                          (find-files "." "Cargo.lock$"))
-                (for-each generate-all-checksums
-                          '("third_party/rust"
-                            "toolkit/library/rust")))))
-          (add-after 'patch-cargo-checksums 'remove-cargo-frozen-flag
-            (lambda _
-              ;; Remove --frozen flag from cargo invokation, otherwise it'll
-              ;; complain that it's not able to change Cargo.lock.
-              ;; https://bugzilla.mozilla.org/show_bug.cgi?id=1726373
-              (substitute* "build/RunCbindgen.py"
-                (("\"--frozen\",") ""))))
-          ;; Fixes issue where each installation directory generates its own
-          ;; profile (see:
-          ;; https://trac.torproject.org/projects/tor/ticket/31457).
-          (add-after 'patch-source-shebangs 'fix-profile-setting
-            (lambda _
-              (substitute* "comm/mail/moz.configure"
-                (("MOZ_DEDICATED_PROFILES, True")
-                 "MOZ_DEDICATED_PROFILES, False"))))
-          (add-after 'prepare-thunderbird-sources 'rename-to-icedove
-            (lambda _
+               (copy-recursively #$thunderbird-comm-source "comm")
+               (delete-file "sourcestamp.txt")
+
+               ;; Adjust the application name.
                (substitute* "comm/mail/confvars.sh"
                  (("MOZ_APP_NAME=thunderbird")
                   "MOZ_APP_NAME=icedove")
                  (("MOZ_UPDATER=1")
                   "MOZ_UPDATER=0"))
+
                ;; Remove branding to comply with Mozilla's trademark policy
                (with-directory-excursion "comm/mail/branding/nightly"
                  (delete-file "content/about-wordmark.svg")
@@ -1244,7 +1254,67 @@ (define-public icedove
                  (("(pref\\(\"extensions.systemAddon.update.enabled\").*" _ m)
                   (string-append m ", false);"))
                  (("(pref\\(\"lightweightThemes.update.enabled\").*" _ m)
-                 (string-append m ", false);")))))
+                  (string-append m ", false);")))
+
+               ;; Step out of the directory and create the tarball.
+               (chdir "..")
+               (format #t "Packing Icedove source tarball...~%")
+               (force-output)
+               (setenv "XZ_DEFAULTS" (string-join (%xz-parallel-args)))
+               (invoke "tar" "cfa" #$output
+                       "--mtime=@315619200" ;1980-01-02 UTC
+                       "--owner=root:0"
+                       "--group=root:0"
+                       "--sort=name"
+                       #$name))))))))
+
+(define-public icedove
+  (package
+    (name "icedove")
+    (version %icedove-version)
+    (source icedove-source)
+    (properties
+     `((cpe-name . "thunderbird_esr")))
+    (build-system gnu-build-system)
+    (arguments
+     (list
+      #:tests? #f                             ;no check target
+      #:imported-modules %cargo-utils-modules ;for `generate-all-checksums'
+      #:modules `((guix build utils)          ;find-files
+                  (sxml simple)
+                  (ice-9 regex)
+                  ,@%gnu-build-system-modules)
+      #:phases
+      #~(modify-phases %standard-phases
+          (add-after 'patch-source-shebangs 'patch-cargo-checksums
+            (lambda _
+              (use-modules (guix build cargo-utils))
+              (let ((null-hash "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934\
+ca495991b7852b855"))
+                (for-each (lambda (file)
+                            (format #t "patching checksums in ~a~%" file)
+                            (substitute* file
+                              (("^checksum = \".*\"")
+                               (string-append "checksum = \"" null-hash "\""))))
+                          (find-files "." "Cargo.lock$"))
+                (for-each generate-all-checksums
+                          '("third_party/rust"
+                            "toolkit/library/rust")))))
+          (add-after 'patch-cargo-checksums 'remove-cargo-frozen-flag
+            (lambda _
+              ;; Remove --frozen flag from cargo invokation, otherwise it'll
+              ;; complain that it's not able to change Cargo.lock.
+              ;; https://bugzilla.mozilla.org/show_bug.cgi?id=1726373
+              (substitute* "build/RunCbindgen.py"
+                (("\"--frozen\",") ""))))
+          ;; Fixes issue where each installation directory generates its own
+          ;; profile (see:
+          ;; https://trac.torproject.org/projects/tor/ticket/31457).
+          (add-after 'patch-source-shebangs 'fix-profile-setting
+            (lambda _
+              (substitute* "comm/mail/moz.configure"
+                (("MOZ_DEDICATED_PROFILES, True")
+                 "MOZ_DEDICATED_PROFILES, False"))))
           (add-after 'build 'neutralize-store-references
             (lambda _
               ;; Mangle the store references to compilers & other build tools in