Fix Bug#30946

* doc/misc/tramp.texi (Multi-hops): Mention host name checks.

* lisp/net/tramp.el (tramp-set-syntax, tramp-dissect-file-name)
(tramp-debug-message, tramp-handle-shell-command):
* lisp/net/tramp-adb.el (tramp-adb-handle-shell-command):
* lisp/net/tramp-archive.el (tramp-archive-file-name-handler)
(tramp-archive-dissect-file-name):
* lisp/net/tramp-gvfs.el (tramp-gvfs-file-name-handler): Adapt callees.

* lisp/net/tramp-compat.el (tramp-compat-user-error): Move defsubst ---

* lisp/net/tramp-sh.el (tramp-compute-multi-hops): Check for proper
host names in multi-hop.  (Bug#30946)

* lisp/net/tramp.el (tramp-user-error): ... here.  Make it a defun.

* test/lisp/net/tramp-tests.el (tramp-test03-file-name-host-rules):
New test.

1 files changed, 4 insertions, 2 deletions

diff --git a/doc/misc/tramp.texi b/doc/misc/tramp.texi
index 31439043435..f0ea073ed09 100644
--- a/doc/misc/tramp.texi
+++ b/doc/misc/tramp.texi
@@ -1408,8 +1408,10 @@ Opening @file{@trampfn{sudo,randomhost.your.domain,}} first connects
 to @samp{randomhost.your.domain} via @code{ssh} under your account
 name, and then performs @code{sudo -u root} on that host.
 
-It is key for the sudo method in the above example to be applied on
-the host after reaching it and not on the local host.
+It is key for the @option{sudo} method in the above example to be
+applied on the host after reaching it and not on the local host.
+@value{tramp} checks therefore, that the host name for such hops
+matches the host name of the previous hop.
 
 @var{host}, @var{user} and @var{proxy} can also take Lisp forms.  These
 forms when evaluated must return either a string or @code{nil}.