40391: Add WARN_NESTED_VAR option and functions -W.

These are companions to WARN_CREATED_GLOBAL, warning when a variable
from an enclosing scope is altered.

5 files changed, 71 insertions, 31 deletions

diff --git a/Src/builtin.c b/Src/builtin.c
index 7a04a79a7..2fb1a70a4 100644
--- a/Src/builtin.c
+++ b/Src/builtin.c
@@ -46,7 +46,7 @@ static struct builtin builtins[] =
     BUILTIN(".", BINF_PSPECIAL, bin_dot, 1, -1, 0, NULL, NULL),
     BUILTIN(":", BINF_PSPECIAL, bin_true, 0, -1, 0, NULL, NULL),
     BUILTIN("alias", BINF_MAGICEQUALS | BINF_PLUSOPTS, bin_alias, 0, -1, 0, "Lgmrs", NULL),
-    BUILTIN("autoload", BINF_PLUSOPTS, bin_functions, 0, -1, 0, "dmktrRTUwXz", "u"),
+    BUILTIN("autoload", BINF_PLUSOPTS, bin_functions, 0, -1, 0, "dmktrRTUwWXz", "u"),
     BUILTIN("bg", 0, bin_fg, 0, -1, BIN_BG, NULL, NULL),
     BUILTIN("break", BINF_PSPECIAL, bin_break, 0, 1, BIN_BREAK, NULL, NULL),
     BUILTIN("bye", 0, bin_break, 0, 1, BIN_EXIT, NULL, NULL),
@@ -72,7 +72,7 @@ static struct builtin builtins[] =
     BUILTIN("fc", 0, bin_fc, 0, -1, BIN_FC, "aAdDe:EfiIlLmnpPrRt:W", NULL),
     BUILTIN("fg", 0, bin_fg, 0, -1, BIN_FG, NULL, NULL),
     BUILTIN("float", BINF_PLUSOPTS | BINF_MAGICEQUALS | BINF_PSPECIAL | BINF_ASSIGN, (HandlerFunc)bin_typeset, 0, -1, 0, "E:%F:%HL:%R:%Z:%ghlprtux", "E"),
-    BUILTIN("functions", BINF_PLUSOPTS, bin_functions, 0, -1, 0, "kmMtTuUx:z", NULL),
+    BUILTIN("functions", BINF_PLUSOPTS, bin_functions, 0, -1, 0, "kmMtTuUWx:z", NULL),
     BUILTIN("getln", 0, bin_read, 0, -1, 0, "ecnAlE", "zr"),
     BUILTIN("getopts", 0, bin_getopts, 2, -1, 0, NULL, NULL),
     BUILTIN("hash", BINF_MAGICEQUALS, bin_hash, 0, -1, 0, "Ldfmrv", NULL),
@@ -796,8 +796,8 @@ set_pwd_env(void)
 	unsetparam_pm(pm, 0, 1);
     }
 
-    setsparam("PWD", ztrdup(pwd));
-    setsparam("OLDPWD", ztrdup(oldpwd));
+    assignsparam("PWD", ztrdup(pwd), 0);
+    assignsparam("OLDPWD", ztrdup(oldpwd), 0);
 
     pm = (Param) paramtab->getnode(paramtab, "PWD");
     if (!(pm->node.flags & PM_EXPORTED))
@@ -3068,6 +3068,10 @@ bin_functions(char *name, char **argv, Options ops, int func)
 	on |= PM_TAGGED_LOCAL;
     else if (OPT_PLUS(ops,'T'))
 	off |= PM_TAGGED_LOCAL;
+    if (OPT_MINUS(ops,'W'))
+	on |= PM_WARNNESTED;
+    else if (OPT_PLUS(ops,'W'))
+	off |= PM_WARNNESTED;
     roff = off;
     if (OPT_MINUS(ops,'z')) {
 	on |= PM_ZSHSTORED;
diff --git a/Src/exec.c b/Src/exec.c
index 6c8264394..8f4969f52 100644
--- a/Src/exec.c
+++ b/Src/exec.c
@@ -2379,9 +2379,7 @@ addvars(Estate state, Wordcode pc, int addflags)
      * to be restored after the command, since then the assignment
      * is implicitly scoped.
      */
-    flags = (!(addflags & ADDVAR_RESTORE) &&
-	     locallevel > forklevel && isset(WARNCREATEGLOBAL)) ?
-	ASSPM_WARN_CREATE : 0;
+    flags = !(addflags & ADDVAR_RESTORE) ? ASSPM_WARN : 0;
     xtr = isset(XTRACE);
     if (xtr) {
 	printprompt4();
@@ -5431,6 +5429,14 @@ doshfunc(Shfunc shfunc, LinkList doshargs, int noreturnval)
 	    else
 		opts[XTRACE] = 0;
 	}
+	if (flags & PM_WARNNESTED)
+	    opts[WARNNESTEDVAR] = 1;
+	else if (oflags & PM_WARNNESTED) {
+	    if (shfunc->node.nam == ANONYMOUS_FUNCTION_NAME)
+		flags |= PM_WARNNESTED;
+	    else
+		opts[WARNNESTEDVAR] = 0;
+	}
 	ooflags = oflags;
 	/*
 	 * oflags is static, because we compare it on the next recursive
@@ -5549,6 +5555,7 @@ doshfunc(Shfunc shfunc, LinkList doshargs, int noreturnval)
 	    opts[PRINTEXITVALUE] = saveopts[PRINTEXITVALUE];
 	    opts[LOCALOPTIONS] = saveopts[LOCALOPTIONS];
 	    opts[LOCALLOOPS] = saveopts[LOCALLOOPS];
+	    opts[WARNNESTEDVAR] = saveopts[WARNNESTEDVAR];
 	}
 
 	if (opts[LOCALLOOPS]) {
diff --git a/Src/options.c b/Src/options.c
index 4729ba54a..e0b67d205 100644
--- a/Src/options.c
+++ b/Src/options.c
@@ -258,6 +258,7 @@ static struct optname optns[] = {
 {{NULL, "verbose",	      0},			 VERBOSE},
 {{NULL, "vi",		      0},			 VIMODE},
 {{NULL, "warncreateglobal",   OPT_EMULATE},		 WARNCREATEGLOBAL},
+{{NULL, "warnnestedvar",      OPT_EMULATE},		 WARNNESTEDVAR},
 {{NULL, "xtrace",	      0},			 XTRACE},
 {{NULL, "zle",		      OPT_SPECIAL},		 USEZLE},
 {{NULL, "braceexpand",	      OPT_ALIAS}, /* ksh/bash */ -IGNOREBRACES},
diff --git a/Src/params.c b/Src/params.c
index d4904666f..ebdd25225 100644
--- a/Src/params.c
+++ b/Src/params.c
@@ -2849,20 +2849,47 @@ gethkparam(char *s)
     return NULL;
 }
 
+/*
+ * Function behind WARNCREATEGLOBAL and WARNNESTEDVAR option.
+ *
+ * For WARNNESTEDVAR:
+ * Called when the variable is created.
+ * Apply heuristics to see if this variable was just created
+ * globally but in a local context.
+ *
+ * For WARNNESTEDVAR:
+ * Called when the variable already exists and is set.
+ * Apply heuristics to see if this variable is setting
+ * a variable that was created in a less nested function
+ * or globally.
+ */
+
 /**/
 static void
-check_warn_create(Param pm, const char *pmtype)
+check_warn_pm(Param pm, const char *pmtype, int created)
 {
     Funcstack i;
 
-    if (pm->level != 0 || (pm->node.flags & PM_SPECIAL))
+    if (created && isset(WARNCREATEGLOBAL)) {
+	if (locallevel <= forklevel || pm->level != 0)
+	    return;
+    } else if (!created && isset(WARNNESTEDVAR)) {
+	if (pm->level >= locallevel)
+	    return;
+    } else
+	return;
+
+    if (pm->node.flags & PM_SPECIAL)
 	return;
 
     for (i = funcstack; i; i = i->prev) {
 	if (i->tp == FS_FUNC) {
+	    char *msg;
 	    DPUTS(!i->name, "funcstack entry with no name");
-	    zwarn("%s parameter %s created globally in function %s",
-		  pmtype, pm->node.nam, i->name);
+	    msg = created ?
+		"%s parameter %s created globally in function %s" :
+		"%s parameter %s set in enclosing scope in function %s";
+	    zwarn(msg, pmtype, pm->node.nam, i->name);
 	    break;
 	}
     }
@@ -2923,8 +2950,8 @@ assignsparam(char *s, char *val, int flags)
 	/* errflag |= ERRFLAG_ERROR; */
 	return NULL;
     }
-    if (flags & ASSPM_WARN_CREATE)
-	check_warn_create(v->pm, "scalar");
+    if (flags & ASSPM_WARN)
+	check_warn_pm(v->pm, "scalar", flags & ASSPM_WARN_CREATE);
     if (flags & ASSPM_AUGMENT) {
 	if (v->start == 0 && v->end == -1) {
 	    switch (PM_TYPE(v->pm->node.flags)) {
@@ -3005,9 +3032,7 @@ assignsparam(char *s, char *val, int flags)
 mod_export Param
 setsparam(char *s, char *val)
 {
-    return assignsparam(
-	s, val, isset(WARNCREATEGLOBAL) && locallevel > forklevel ?
-	ASSPM_WARN_CREATE : 0);
+    return assignsparam(s, val, ASSPM_WARN);
 }
 
 /**/
@@ -3074,8 +3099,8 @@ assignaparam(char *s, char **val, int flags)
 	    return NULL;
 	}
 
-    if (flags & ASSPM_WARN_CREATE)
-	check_warn_create(v->pm, "array");
+    if (flags & ASSPM_WARN)
+	check_warn_pm(v->pm, "array", flags & ASSPM_WARN_CREATE);
     if (flags & ASSPM_AUGMENT) {
     	if (v->start == 0 && v->end == -1) {
 	    if (PM_TYPE(v->pm->node.flags) & PM_ARRAY) {
@@ -3103,9 +3128,7 @@ assignaparam(char *s, char **val, int flags)
 mod_export Param
 setaparam(char *s, char **aval)
 {
-    return assignaparam(
-	s, aval, isset(WARNCREATEGLOBAL) && locallevel > forklevel ?
-	ASSPM_WARN_CREATE : 0);
+    return assignaparam(s, aval, ASSPM_WARN);
 }
 
 /**/
@@ -3134,7 +3157,7 @@ sethparam(char *s, char **val)
     queue_signals();
     if (!(v = fetchvalue(&vbuf, &s, 1, SCANPM_ASSIGNING))) {
 	createparam(t, PM_HASHED);
-	checkcreate = isset(WARNCREATEGLOBAL) && locallevel > forklevel;
+	checkcreate = 1;
     } else if (!(PM_TYPE(v->pm->node.flags) & PM_HASHED) &&
 	     !(v->pm->node.flags & PM_SPECIAL)) {
 	unsetparam(t);
@@ -3148,8 +3171,7 @@ sethparam(char *s, char **val)
 	    /* errflag |= ERRFLAG_ERROR; */
 	    return NULL;
 	}
-    if (checkcreate)
-	check_warn_create(v->pm, "associative array");
+    check_warn_pm(v->pm, "associative array", checkcreate);
     setarrvalue(v, val);
     unqueue_signals();
     return v->pm;
@@ -3214,8 +3236,9 @@ setnparam(char *s, mnumber val)
 	    unqueue_signals();
 	    return NULL;
 	}
-	if (!was_unset && isset(WARNCREATEGLOBAL) && locallevel > forklevel)
-	    check_warn_create(v->pm, "numeric");
+	check_warn_pm(v->pm, "numeric", !was_unset);
+    } else {
+	check_warn_pm(v->pm, "numeric", 0);
     }
     setnumvalue(v, val);
     unqueue_signals();
@@ -3250,10 +3273,7 @@ setiparam_no_convert(char *s, zlong val)
      */
     char buf[BDIGBUFSIZE];
     convbase(buf, val, 10);
-    return assignsparam(
-	s, ztrdup(buf),
-	isset(WARNCREATEGLOBAL) && locallevel > forklevel ?
-	ASSPM_WARN_CREATE : 0);
+    return assignsparam(s, ztrdup(buf), ASSPM_WARN);
 }
 
 /* Unset a parameter */
diff --git a/Src/zsh.h b/Src/zsh.h
index 7d18333be..d0222605b 100644
--- a/Src/zsh.h
+++ b/Src/zsh.h
@@ -1815,6 +1815,7 @@ struct tieddata {
 #define PM_HIDE		(1<<14)	/* Special behaviour hidden by local        */
 #define PM_CUR_FPATH    (1<<14) /* (function): can use $fpath with filename */
 #define PM_HIDEVAL	(1<<15)	/* Value not shown in `typeset' commands    */
+#define PM_WARNNESTED   (1<<15) /* (function): non-recursive WARNNESTEDVAR  */
 #define PM_TIED 	(1<<16)	/* array tied to colon-path or v.v.         */
 #define PM_TAGGED_LOCAL (1<<16) /* (function): non-recursive PM_TAGGED      */
 
@@ -2016,9 +2017,15 @@ struct paramdef {
  * Flags for assignsparam and assignaparam.
  */
 enum {
+    /* Add to rather than override value */
     ASSPM_AUGMENT = 1 << 0,
+    /* Test for warning if creating global variable in function */
     ASSPM_WARN_CREATE = 1 << 1,
-    ASSPM_ENV_IMPORT = 1 << 2
+    /* Test for warning if using nested variable in function */
+    ASSPM_WARN_NESTED = 1 << 2,
+    ASSPM_WARN = (ASSPM_WARN_CREATE|ASSPM_WARN_NESTED),
+    /* Import from environment, so exercise care evaluating value */
+    ASSPM_ENV_IMPORT = 1 << 3,
 };
 
 /* node for named directory hash table (nameddirtab) */
@@ -2400,6 +2407,7 @@ enum {
     VERBOSE,
     VIMODE,
     WARNCREATEGLOBAL,
+    WARNNESTEDVAR,
     XTRACE,
     USEZLE,
     DVORAK,