patch 9.1.1180: short-description

Problem:  The meaning of <Tab> depends on unspecified behavior
          (after 9.1.1179).
Solution: Return TAB in case bsearch() finds K_TAB.  Rename alt_name to
          pref_name as that's closer to it meaning (zeertzjq).

The man page of bsearch() says:

    The bsearch() function returns a pointer to a matching member of the
    array, or NULL if no match is found.  If there are multiple elements
    that match the key, the element returned is unspecified.

So it's possible that bsearch() finds K_TAB instead of TAB when trying
to get the key code for <Tab>. Actually, it can happen when adding a
single key to end of the table:

closes: #16821

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

diff --git a/src/misc2.c b/src/misc2.c
index 151745ca2..90f108a24 100644
--- a/src/misc2.c
+++ b/src/misc2.c
@@ -1141,7 +1141,8 @@ static struct key_name_entry
     {TRUE, K_XRIGHT, STRING_INIT("xRight"), NULL},
     {TRUE, K_XUP, STRING_INIT("xUp"), NULL},
     {TRUE, K_ZEND, STRING_INIT("zEnd"), NULL},
-    {TRUE, K_ZHOME, STRING_INIT("zHome"), NULL}
+    {TRUE, K_ZHOME, STRING_INIT("zHome"), NULL},
+    {TRUE, -1, STRING_INIT("zzDummyKey"), NULL}
     // NOTE: When adding a long name update MAX_KEY_NAME_LEN.
 };
 #undef STRING_INIT

Meanwhile IDX_KEYNAME_TAB doesn't do anything, as TAB and K_TAB have the
same name.

Signed-off-by: Christian Brabandt <cb@256bit.org>

src/misc2.c

@@ -930,7 +930,6 @@ static char_u modifier_keys_table[] =
 #define IDX_KEYNAME_NL 101
 #define IDX_KEYNAME_SWD 115
 #define IDX_KEYNAME_SWU 118
-#define IDX_KEYNAME_TAB 124
 
 #define STRING_INIT(s) \
     {(char_u *)(s), STRLEN_LITERAL(s)}
@@ -939,7 +938,7 @@ static struct key_name_entry
     int		enabled;	    // is this entry available (TRUE/FALSE)?
     int		key;		    // special key code or ascii value
     string_T	name;		    // name of key
-    string_T	*alt_name;	    // pointer to alternative key name
+    string_T	*pref_name;	    // pointer to preferred key name
 				    // (may be NULL or point to the name in another entry)
 } key_names_table[] =
 // Must be sorted by the 'name.string' field in ascending order because it is used by bsearch()!
@@ -1065,7 +1064,7 @@ static struct key_name_entry
     {TRUE, K_MIDDLERELEASE, STRING_INIT("MiddleRelease"), NULL},
     {TRUE, K_MOUSE, STRING_INIT("Mouse"), NULL},
     {TRUE, K_MOUSEDOWN, STRING_INIT("MouseDown"),
-	&key_names_table[IDX_KEYNAME_SWU].name},		    // OBSOLETE: Use ScrollWheelUP instead
+	&key_names_table[IDX_KEYNAME_SWU].name},		    // OBSOLETE: Use ScrollWheelUp instead
     {TRUE, K_MOUSEMOVE, STRING_INIT("MouseMove"), NULL},
     {TRUE, K_MOUSEUP, STRING_INIT("MouseUp"),
 	&key_names_table[IDX_KEYNAME_SWD].name},		    // OBSELETE: Use ScrollWheelDown instead
@@ -1114,8 +1113,7 @@ static struct key_name_entry
 	K_SNR, STRING_INIT("SNR"), NULL},
     {TRUE, ' ', STRING_INIT("Space"), NULL},
     {TRUE, TAB, STRING_INIT("Tab"), NULL},
-    {TRUE, K_TAB, STRING_INIT("Tab"),
-	&key_names_table[IDX_KEYNAME_TAB].name},
+    {TRUE, K_TAB, STRING_INIT("Tab"), NULL},
     {TRUE, K_UNDO, STRING_INIT("Undo"), NULL},
     {TRUE, K_UP, STRING_INIT("Up"), NULL},
     {
@@ -1325,8 +1323,8 @@ get_special_key_name(int c, int modifiers)
     {
 	string_T    *s;
 
-	if (key_names_table[table_idx].alt_name != NULL)
-	    s = key_names_table[table_idx].alt_name;
+	if (key_names_table[table_idx].pref_name != NULL)
+	    s = key_names_table[table_idx].pref_name;
 	else
 	    s = &key_names_table[table_idx].name;
 
@@ -1801,7 +1799,7 @@ get_special_key_code(char_u *name)
 	target.key = 0;
 	target.name.string = name;
 	target.name.length = 0;
-	target.alt_name = NULL;
+	target.pref_name = NULL;
 
 	entry = (struct key_name_entry *)bsearch(
 	    &target,
@@ -1810,7 +1808,12 @@ get_special_key_code(char_u *name)
 	    sizeof(key_names_table[0]),
 	    cmp_key_name_entry);
 	if (entry != NULL && entry->enabled)
-	    return entry->key;
+	{
+	    int key = entry->key;
+	    // Both TAB and K_TAB have name "Tab", and it's unspecified which
+	    // one bsearch() will return.  TAB is the expected one.
+	    return key == K_TAB ? TAB : key;
+	}
     }
 
     return 0;
@@ -1822,8 +1825,8 @@ get_key_name(int i)
     if (i < 0 || i >= (int)ARRAY_LENGTH(key_names_table))
 	return NULL;
 
-    return (key_names_table[i].alt_name != NULL) ?
-	key_names_table[i].alt_name->string :
+    return (key_names_table[i].pref_name != NULL) ?
+	key_names_table[i].pref_name->string :
 	key_names_table[i].name.string;
 }
 

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1180,
 /**/
     1179,
 /**/