[vim/vim] serverlist() fails when there is no connection to the X server (PR #21124)
thinca
Problem
Since patch 9.2.0818 (#20716), serverlist() gives E240: No connection to the X server when the X11 clientserver backend cannot connect to the X server — for example on a Wayland-only system or with $DISPLAY unset. Before that patch it returned an empty result.
Why this is a regression
- It contradicts the documentation.
:help serverlist()says "When there are no servers or the information is not available an empty string is returned", and 9.2.0818 did not update it. - The error was deliberately removed before. Patch 6.0.191: "When no servers are available serverlist() gives an error instead of returning an empty string" → "Don't give an error message". Patch 6.1.349 did the same for
--serverlistwhen the display cannot be opened. - Entry points and backends now disagree. In exactly the situation where the function fails, the
--serverlistcommand line argument still prints an empty list, and the socket backend still returns an empty list. - The return type is broken on the failing path.
rettvis never set, so the result is a Number rather than a String or a List:silent! let r = serverlist() echo type(r) " 0 (Number), r == 0
Solution
Do not give an error when the X server cannot be reached; return an empty string, or an empty List when the "list" option is used.
The "list" option now always results in a List when no server names are available. That is the type inconsistency 9.2.0818 set out to fix — serverlist({'list': 1}) returning a String — and it is fixed for every backend, including a build without +clientserver.
Tests
Test_clientserver_serverlist_without_x11() now checks that a child Vim without $DISPLAY returns '' from serverlist() and [] from serverlist(#{list: v:true}). It fails before the fix and passes after it:
# before
Found errors in Test_clientserver_serverlist_without_x11():
... line 36: Expected 0 but got 1
# after
Executed 1 test
The child process wraps the calls in a try/catch because an error in a sourced script only aborts the failing command: without it the assertion is never reached, v:errors stays empty and the test passes even when serverlist() fails (verified: exit code 0).
The catch /E240:/ workaround that 9.2.0818 added to Test_remote_serverlist() in test_vim9_builtin.vim is no longer needed and is removed, so that test checks the return types again.
🤖 Generated with Claude Code
You can view, comment on, or merge this pull request online at:
https://github.com/vim/vim/pull/21124
Commit Summary
- deb6848 serverlist() fails when there is no connection to the X server
File Changes
(4 files)
- M runtime/doc/builtin.txt (3)
- M src/clientserver.c (17)
- M src/testdir/test_clientserver.vim (18)
- M src/testdir/test_vim9_builtin.vim (12)
Patch Links:
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Christian Brabandt
chrisbra left a comment (vim/vim#21124)thanks
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