Improve completions for ssh by completing from history

CHANGELOG.md

@@ -69,6 +69,7 @@ This section is for changes merged to the `major` branch that are not also merge
   - `brew`
   - `diskutil`
   - `yarn`
+  - `ssh` (#4344)
 
 --
 

share/completions/ssh.fish

@@ -41,3 +41,14 @@ complete -c ssh -s X -d "Enable X11 forwarding"
 complete -c ssh -s L -d "Locally forwarded ports"
 complete -c ssh -s R -d "Remotely forwarded ports"
 complete -c ssh -s D -d "Dynamic port forwarding"
+
+# Also look up hosts from the history
+function __ssh_history_completions --argument limit
+	if string match -q ""
+		set limit 100
+	end
+
+	history --prefix ssh | sed -n "s/.* \([A-Za-z0-9._:-]\+@[A-Za-z0-9._:-]\+\).*/\1/p" | head -n $limit
+end
+
+complete -k -c ssh -a '(__ssh_history_completions 100)' -f