From 9d47e8398d299e53ffe4e7ddf3731d2fedae9948 Mon Sep 17 00:00:00 2001
From: "Barton E. Schaefer" <schaefer@zsh.org>
Date: Tue, 13 May 2014 08:16:50 -0700
Subject: 32609: [[ $var ]] behaves as [[ -n $var ]] for bash/ksh compatibility

Also restore ksh [ -t ] compatibility when POSIX_BUILTINS is not set, and
allow operators defined by modules to be called with no arguments, although
this affects only runtime interpretation, not parsing.
---
 ChangeLog         |  8 ++++++++
 Src/parse.c       | 41 ++++++++++++++++++++++++++++-------------
 Test/C02cond.ztst |  8 ++++++++
 3 files changed, 44 insertions(+), 13 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 58e1ffa2d..a50a756c9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2014-05-13  Barton E. Schaefer  <schaefer@zsh.org>
+
+	* 32609: Src/parse.c, Test/CO2cond.ztst: [[ $var ]] behaves as
+	[[ -n $var ]] for bash/ksh compatibility; restore ksh [ -t ]
+	compatibility when POSIX_BUILTINS is not set; allow operators
+	defined by modules to be called with no arguments, although
+	this affects only runtime interpretation, not parsing.
+
 2014-05-09  Peter Stephenson  <p.stephenson@samsung.com>
 
 	* Eric Cook: 32602: Doc/Zsh/grammar.yo: status of try + always
diff --git a/Src/parse.c b/Src/parse.c
index 530a07033..5f1303f1c 100644
--- a/Src/parse.c
+++ b/Src/parse.c
@@ -2068,6 +2068,9 @@ par_cond_2(void)
 	    /* one argument: [ foo ] is equivalent to [ -n foo ] */
 	    s1 = tokstr;
 	    condlex();
+	    /* ksh behavior: [ -t ] means [ -t 1 ]; bash disagrees */
+	    if (unset(POSIXBUILTINS) && !strcmp(s1, "-t"))
+		return par_cond_double(s1, dupstring("1"));
 	    return par_cond_double(dupstring("-n"), s1);
 	}
 	if (testargs[1]) {
@@ -2086,6 +2089,10 @@ par_cond_2(void)
 		return par_cond_triple(s1, s2, s3);
 	    }
 	}
+	/*
+	 * We fall through here on any non-numeric infix operator
+	 * or any other time there are at least two arguments.
+	 */
     }
     if (tok == BANG) {
 	/*
@@ -2114,18 +2121,20 @@ par_cond_2(void)
 	condlex();
 	return r;
     }
+    s1 = tokstr;
+    dble = (s1 && *s1 == '-'
+	    && (condlex != testlex
+		|| strspn(s1+1, "abcdefghknoprstuwxzLONGS") == 1)
+	    && !s1[2]);
     if (tok != STRING) {
-	if (tok && tok != LEXERR && condlex == testlex) {
-	    s1 = tokstr;
+	/* Check first argument for [[ STRING ]] re-interpretation */
+	if (s1 /* tok != DOUTBRACK && tok != DAMPER && tok != DBAR */
+	    && tok != LEXERR && (!dble || condlex == testlex)) {
 	    condlex();
-	    return par_cond_double("-n", s1);
+	    return par_cond_double(dupstring("-n"), s1);
 	} else
 	    YYERROR(ecused);
     }
-    s1 = tokstr;
-    if (condlex == testlex)
-	dble = (*s1 == '-' && strspn(s1+1, "abcdefghknoprstuwxzLONGS") == 1
-		  && !s1[2]);
     condlex();
     if (tok == INANG || tok == OUTANG) {
 	enum lextok xtok = tok;
@@ -2140,15 +2149,21 @@ par_cond_2(void)
 	return 1;
     }
     if (tok != STRING) {
-	if (tok != LEXERR && condlex == testlex) {
-	    if (!dble)
-		return par_cond_double("-n", s1);
-	    else if (!strcmp(s1, "-t"))
-		return par_cond_double(s1, "1");
+	/*
+	 * Check second argument in case semantics e.g. [ = -a = ]
+	 * mean we have to go back and fix up the first one
+	 */
+	if (tok != LEXERR) {
+	    if (!dble || condlex == testlex)
+		return par_cond_double(dupstring("-n"), s1);
+	    else
+		return par_cond_multi(s1, newlinklist());
 	} else
 	    YYERROR(ecused);
     }
-    s2 = tokstr;
+    s2 = tokstr;   
+    if (condlex != testlex)
+	dble = (s2 && *s2 == '-' && !s2[2]);
     incond++;			/* parentheses do globbing */
     condlex();
     incond--;			/* parentheses do grouping */
diff --git a/Test/C02cond.ztst b/Test/C02cond.ztst
index 94fca8b68..69001476c 100644
--- a/Test/C02cond.ztst
+++ b/Test/C02cond.ztst
@@ -349,6 +349,14 @@ F:Failures in these cases do not indicate a problem in the shell.
 >0
 >1
 
+  foo=''
+  [[ $foo ]] || print foo is empty
+  foo=full
+  [[ $foo ]] && print foo is full
+0:bash compatibility with single [[ ... ]] argument
+>foo is empty
+>foo is full
+
 %clean
   # This works around a bug in rm -f in some versions of Cygwin
   chmod 644 unmodish
-- 
cgit 1.4.1