patch 8.2.4510: Vim9: shortening commands leads to confusing scriptv8.2.4510

Problem:    Vim9: shortening commands leads to confusing script.
Solution:   In Vim9 script require at least ":cont" for ":continue", "const"
            instead of "cons", "break" instead of "brea", "catch" instead of
            "cat", "else" instead of "el" "elseif" instead of "elsei" "endfor"
            instead of "endfo" "endif" instead of "en" "endtry" instead of
            "endt", "finally" instead of "fina", "throw" instead of "th",
            "while" instead of "wh".

1 files changed, 18 insertions, 7 deletions

diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index 287045bc5d..6b2bdd4e5c 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -3745,16 +3745,27 @@ find_ex_command(
 							    (size_t)len) == 0)
 	    {
 #ifdef FEAT_EVAL
-		if (full != NULL
-			   && cmdnames[(int)eap->cmdidx].cmd_name[len] == NUL)
+		if (full != NULL && cmdnames[eap->cmdidx].cmd_name[len] == NUL)
 		    *full = TRUE;
 #endif
 		break;
 	    }
 
-	// :Print and :mode are not supported in Vim9 script
-	if (vim9 && (eap->cmdidx == CMD_mode || eap->cmdidx == CMD_Print))
-	    eap->cmdidx = CMD_SIZE;
+	// :Print and :mode are not supported in Vim9 script.
+	// Some commands cannot be shortened in Vim9 script.
+	// ":continue" needs at least ":cont", since ":con" looks weird.
+	if (vim9 && eap->cmdidx != CMD_SIZE)
+	{
+	    if (eap->cmdidx == CMD_mode || eap->cmdidx == CMD_Print)
+		eap->cmdidx = CMD_SIZE;
+	    else if (((cmdnames[eap->cmdidx].cmd_argt & EX_WHOLE)
+			  && len < (int)STRLEN(cmdnames[eap->cmdidx].cmd_name))
+		      || (eap->cmdidx == CMD_continue && len < 4))
+	    {
+		semsg(_(e_command_cannot_be_shortened), eap->cmd);
+		eap->cmdidx = CMD_SIZE;
+	    }
+	}
 
 	// Do not recognize ":*" as the star command unless '*' is in
 	// 'cpoptions'.
@@ -3775,8 +3786,8 @@ find_ex_command(
 	    eap->cmdidx = CMD_SIZE;
     }
 
-    // ":fina" means ":finally" for backwards compatibility.
-    if (eap->cmdidx == CMD_final && p - eap->cmd == 4)
+    // ":fina" means ":finally" in legacy script, for backwards compatibility.
+    if (eap->cmdidx == CMD_final && p - eap->cmd == 4 && !vim9)
 	eap->cmdidx = CMD_finally;
 
 #ifdef FEAT_EVAL