grafts: Allow the replacement to have a different name.

* guix/build/graft.scm (replace-store-references): REPLACEMENT is now
the full string, not just the hash.
(rewrite-directory)[hash-mapping](valid-suffix?): Remove.
(hash+suffix): Rename to...
(hash+rest): ... this.  Change to return the whole string as the second
element of the list.  Adjust 'match-lambda' expression accordingly;
check whether the string length of the origin and replacement match.
* tests/grafts.scm ("graft-derivation, grafted item uses a different
name"): New test.
* doc/guix.texi (Security Updates): Update sentence on the name/version
restriction.

1 files changed, 4 insertions, 4 deletions

diff --git a/doc/guix.texi b/doc/guix.texi
index 73570277f6..9bd8b43582 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -11782,10 +11782,10 @@ minute for an ``average'' package on a recent machine.  Grafting is
 recursive: when an indirect dependency requires grafting, then grafting
 ``propagates'' up to the package that the user is installing.
 
-Currently, the graft and the package it replaces (@var{bash-fixed} and
-@var{bash} in the example above) must have the exact same @code{name}
-and @code{version} fields.  This restriction mostly comes from the fact
-that grafting works by patching files, including binary files, directly.
+Currently, the length of the name and version of the graft and that of
+the package it replaces (@var{bash-fixed} and @var{bash} in the example
+above) must be equal.  This restriction mostly comes from the fact that
+grafting works by patching files, including binary files, directly.
 Other restrictions may apply: for instance, when adding a graft to a
 package providing a shared library, the original shared library and its
 replacement must have the same @code{SONAME} and be binary-compatible.