Versioneer does not work in the Guix build container because:

* VCS information is unavailable
* the build directory does not have the supported "$name-$version" format
* as of 0.21, versioneer has no way to override the discovered values

This patch adds support for extracting version from the
'/tmp/guix-build-foo-0.1.drv-0' style directories created by the daemon.

diff --git a/src/from_parentdir.py b/src/from_parentdir.py
index 69ada9a..e0fac8f 100644
--- a/src/from_parentdir.py
+++ b/src/from_parentdir.py
@@ -15,6 +15,21 @@ def versions_from_parentdir(parentdir_prefix, root, verbose):
             return {"version": dirname[len(parentdir_prefix):],
                     "full-revisionid": None,
                     "dirty": False, "error": None, "date": None}
+        # Guix specific patch: try extracting the version from the build
+        # directory.
+        elif dirname.startswith("guix-build-"):
+            delimiter = dirname.rindex(".drv-")
+            name_and_version = dirname[11:delimiter]
+            if name_and_version.startswith(parentdir_prefix):
+                guix_version = name_and_version[len(parentdir_prefix):]
+            elif name_and_version.startswith("python-{}".format(parentdir_prefix)):
+                guix_version = name_and_version[(7 + len(parentdir_prefix)):]
+            else:
+                break
+            return {"version": guix_version,
+                    "full-revisionid": None,
+                    "dirty": False, "error": None, "date": None}
+
         rootdirs.append(root)
         root = os.path.dirname(root)  # up a level
 
x/log/tests/store-deduplication.scm'>
<input type='hidden' name='id' value='05044a54468e091ead1dfa24662df02cd0929ad8'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=05044a54468e091ead1dfa24662df02cd0929ad8'>root</a>/<a href='/guix/log/tests?id=05044a54468e091ead1dfa24662df02cd0929ad8'>tests</a>/<a href='/guix/log/tests/store-deduplication.scm?id=05044a54468e091ead1dfa24662df02cd0929ad8'>store-deduplication.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/tests/store-deduplication.scm?id=05044a54468e091ead1dfa24662df02cd0929ad8&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2022-12-10 10:56:48 +0100'>2022-12-10</span></td><td><a href='/guix/commit/tests/store-deduplication.scm?id=b129026e2e242e9068158ae6e6fcd8d7c5ea092e'>deduplicate: Use 'sendfile' for small file copies.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/store/deduplication.scm (dump-file/deduplicate): Use 'sendfile'
instead of 'dump-port'.
* tests/store-deduplication.scm ("copy-file/deduplicate, below %deduplication-minimum-size"):
New test.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-11-16 14:34:28 +0100'>2021-11-16</span></td><td><a href='/guix/commit/tests/store-deduplication.scm?id=472a0e82a52a3d5d841e1dfad6b13e26082a5750'>daemon: Do not deduplicate files smaller than 8 KiB.</a><span class='msg-avail'>...<span class='msg-tooltip'>Files smaller than 8 KiB typically represent ~70% of the entries in
/gnu/store/.links but only contribute to ~4% of the space savings
afforded by deduplication.

Not considering these files for deduplication speeds up file insertion
in the store and, more importantly, leaves 'removeUnusedLinks' with
fewer entries to traverse, thereby speeding it up proportionally.

Partly fixes &lt;https://issues.guix.gnu.org/24937&gt;.

* config-daemon.ac: Remove symlink hard link check and CAN_LINK_SYMLINK
definition.
* guix/store/deduplication.scm (%deduplication-minimum-size): New
variable.
(deduplicate)[loop]: Do not recurse when FILE's size is below
%DEDUPLICATION-MINIMUM-SIZE.
(dump-port): New procedure.
(dump-file/deduplicate)[hash]: Turn into...
[dump-and-compute-hash]: ... this thunk.
Call 'deduplicate' only when SIZE is greater than
%DEDUPLICATION-MINIMUM-SIZE; otherwise call 'dump-port'.
* nix/libstore/gc.cc (LocalStore::removeUnusedLinks): Drop files where
st.st_size &lt; deduplicationMinSize.
* nix/libstore/local-store.hh (deduplicationMinSize): New declaration.
* nix/libstore/optimise-store.cc (deduplicationMinSize): New variable.
(LocalStore::optimisePath_): Return when PATH is a symlink or smaller
than 'deduplicationMinSize'.
* tests/derivations.scm ("identical files are deduplicated"): Produce
files bigger than %DEDUPLICATION-MINIMUM-SIZE.
* tests/nar.scm ("restore-file-set with directories (signed, valid)"):
Likewise.
* tests/store-deduplication.scm ("deduplicate, below %deduplication-minimum-size"):
New test.
("deduplicate", "deduplicate, ENOSPC"): Produce files bigger than
%DEDUPLICATION-MINIMUM-SIZE.
* tests/store.scm ("substitute, deduplication"): Likewise.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-12-15 17:32:12 +0100'>2020-12-15</span></td><td><a href='/guix/commit/tests/store-deduplication.scm?id=7530e491b517497b7b8166b5ccecdc3d4cdb468d'>deduplicate: Create the '.links' directory lazily.</a><span class='msg-avail'>...<span class='msg-tooltip'>This avoids repeated (mkdir-p "/gnu/store/.links") calls when
deduplicating lots of files.

* guix/store/deduplication.scm (deduplicate): Remove initial call to
'mkdir-p'.  Add ENOENT case in 'link' exception handler.  Reindent.
* tests/store-deduplication.scm ("deduplicate, ENOSPC"): Check
for (&lt;= links 4) to account for the initial 'link' call.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-12-15 17:32:10 +0100'>2020-12-15</span></td><td><a href='/guix/commit/tests/store-deduplication.scm?id=6a060ff27ff68384d7c90076baa36c349fff689d'>store-copy: 'populate-store' can optionally deduplicate files.</a><span class='msg-avail'>...<span class='msg-tooltip'>Until now deduplication was performed as an additional pass after
copying files, which involve re-traversing all the files that had just
been copied.

* guix/store/deduplication.scm (copy-file/deduplicate): New procedure.
* tests/store-deduplication.scm ("copy-file/deduplicate"): New test.
* guix/build/store-copy.scm (populate-store): Add #:deduplicate?
parameter and honor it.
* tests/gexp.scm ("gexp-&gt;derivation, store copy"): Pass #:deduplicate? #f
to 'populate-store'.
* gnu/build/image.scm (initialize-root-partition): Pass #:deduplicate?
to 'populate-store'.  Pass #:deduplicate? #f to 'register-closure'.
* gnu/build/vm.scm (root-partition-initializer): Likewise.
* gnu/build/install.scm (populate-single-profile-directory): Pass
 #:deduplicate? #f to 'populate-store'.
* gnu/build/linux-initrd.scm (build-initrd): Likewise.
* guix/scripts/pack.scm (self-contained-tarball)[import-module?]: New
procedure.
[build]: Pass it as an argument to 'source-module-closure'.
* guix/scripts/pack.scm (squashfs-image)[build]: Wrap in
'with-extensions'.
* gnu/system/linux-initrd.scm (expression-&gt;initrd)[import-module?]: New
procedure.
[builder]: Pass it to 'source-module-closure'.
* gnu/system/install.scm (cow-store-service-type)[import-module?]: New
procedure.  Pass it to 'source-module-closure'.
</span></span></td><td>Ludovic Courtès</td></tr>