clients to 1 in ci

Before this commit, TLS tests on Ubuntu 22.04 would fail as dropped
connections result with an ECONNABORTED error thrown instead of an empty
read.

.github/workflows/ci.yml

@@ -21,10 +21,10 @@ jobs:
     - name: test-tls
       run: |
         sudo apt-get -y install tcl tcl-tls
-        ./runtest --clients 2 --verbose --tls
+        ./runtest --clients 1 --verbose --tls --config server-threads 3
     - name: cluster-test
       run: |
-        ./runtest-cluster --tls
+        ./runtest-cluster --tls --config server-threads 3
     - name: sentinel test
       run: |
           ./runtest-sentinel

tests/support/keydb.tcl

@@ -66,6 +66,33 @@ proc redis {{server 127.0.0.1} {port 6379} {defer 0} {tls 0} {tlsoptions {}} {re
     interp alias {} ::redis::redisHandle$id {} ::redis::__dispatch__ $id
 }
 
+# On recent versions of tcl-tls/OpenSSL, reading from a dropped connection
+# results with an error we need to catch and mimic the old behavior.
+proc ::redis::redis_safe_read {fd len} {
+    if {$len == -1} {
+        set err [catch {set val [read $fd]} msg]
+    } else {
+        set err [catch {set val [read $fd $len]} msg]
+    }
+    if {!$err} {
+        return $val
+    }
+    if {[string match "*connection abort*" $msg]} {
+        return {}
+    }
+    error $msg
+}
+
+proc ::redis::redis_safe_gets {fd} {
+    if {[catch {set val [gets $fd]} msg]} {
+        if {[string match "*connection abort*" $msg]} {
+            return {}
+        }
+        error $msg
+    }
+    return $val
+}
+
 # This is a wrapper to the actual dispatching procedure that handles
 # reconnection if needed.
 proc ::redis::__dispatch__ {id method args} {
@@ -146,6 +173,10 @@ proc ::redis::__method__read {id fd} {
     ::redis::redis_read_reply $id $fd
 }
 
+proc ::redis::__method__rawread {id fd {len -1}} {
+    return [redis_safe_read $fd $len]
+}
+
 proc ::redis::__method__write {id fd buf} {
     ::redis::redis_write $fd $buf
 }
@@ -192,8 +223,8 @@ proc ::redis::redis_writenl {fd buf} {
 }
 
 proc ::redis::redis_readnl {fd len} {
-    set buf [read $fd $len]
-    read $fd 2 ; # discard CR LF
+    set buf [redis_safe_read $fd $len]
+    redis_safe_read $fd 2 ; # discard CR LF
     return $buf
 }
 
@@ -239,11 +270,11 @@ proc ::redis::redis_read_map {id fd} {
 }
 
 proc ::redis::redis_read_line fd {
-    string trim [gets $fd]
+    string trim [redis_safe_gets $fd]
 }
 
 proc ::redis::redis_read_null fd {
-    gets $fd
+    redis_safe_gets $fd
     return {}
 }
 
@@ -260,7 +291,7 @@ proc ::redis::redis_read_reply {id fd} {
     }
 
     while {1} {
-        set type [read $fd 1]
+        set type [redis_safe_read $fd 1]
         switch -exact -- $type {
             _ {return [redis_read_null $fd]}
             : -

tests/unit/obuf-limits.tcl

@@ -111,7 +111,7 @@ start_server {tags {"obuf-limits"} overrides { server-threads 1 }} {
 
         # Read nothing
         set fd [$rd channel]
-        assert_equal {} [read $fd]
+        assert_equal {} [$rd rawread]
     }
 
     # Note: This test assumes that what's written with one write, will be read by redis in one read.
@@ -151,8 +151,7 @@ start_server {tags {"obuf-limits"} overrides { server-threads 1 }} {
         assert_equal "PONG" [r ping]
         set clients [r client list]
         assert_no_match "*name=multicommands*" $clients
-        set fd [$rd2 channel]
-        assert_equal {} [read $fd]
+        assert_equal {} [$rd2 rawread]
     }
 
     test {Execute transactions completely even if client output buffer limit is enforced} {