commit bash-20170317 snapshot

CWRU/CWRU.chlog

@@ -13362,3 +13362,90 @@ lib/readline/display.c
 lib/readline/readline.c
 	- bind_arrow_keys_internal: add default key bindings for control-
 	  arrow keys, suggested by Per Bothner <per@bothner.com>
+
+				   3/13
+				   ----
+doc/{bash.1,bashref.texi}
+	- clarify the prompt strings the undergo expansion (PS0, PS1, PS2, and
+	  PS4) before being displayed.  Based on a report from Grisha Levit
+	  <grishalevit@gmail.com>
+
+				   3/14
+				   ----
+input.c
+	- bufstream_ungetc: return EOF if being asked to unget a character to
+	  a NULL buffer
+	- buffered_getchar: check buffered_fd is valid and buffers[buffered_fd]
+	  is non-NULL before trying to dereference. Fixes bug reported by
+	  floyd <floyd@floyd.ch>
+
+execute_cmd.c
+	- execute_null_command: if we fork to execute the command, the subshell
+	  is not interactive
+	- execute_null_command: for safety's sake, if a redirection attached
+	  to a null command affects fd 0 or the fd the shell is reading for
+	  input, and the redirection can potentially change or close that file
+	  descriptor, force a fork so the redirection is done in a subshell
+
+				   3/15
+				   ----
+lib/readline/display.c
+	- update_line: if we have to output some bytes, and we are outputting
+	  the prompt string, make sure we correct _rl_last_c_pos if we are
+	  at the wrap offset -- what if all of the characters in the prompt
+	  are invisible, so the visible length is 0?  Fixes display bug
+	  reported by Grisha Levit <grishalevit@gmail.com>
+
+execute_cmd.c
+	- undo_partial_redirects: new function, performs redirections specified
+	  in redirection_undo_list and disposes of them. Intended to be used
+	  to unwind redirections performed before a redirection error
+	- dispose_partial_redirects: new function, disposes of
+	  redirection_undo_list and nulls the list
+	- execute_command_internal: use undo_partial_redirects
+
+execute_cmd.h
+	- undo_partial_redirects: extern declaration
+	- dispose_partial_redirects: extern declaration
+
+subst.c
+	- exp_jump_to_top_level: if we are throwing an expansion error while
+	  expanding a redirection (expanding_redir != 0), undo any undoable
+	  redirections by calling undo_partial_redirects() so we don't leave
+	  any in place
+
+variables.c
+	- initialize_shell_variables: if SHELLOPTS is in the environment,
+	  unset the readonly attribute on any existing variable with that
+	  name. It may have been created by processing a -o option on the
+	  command line.  Fixes issue reported by Stephane Chazelas
+	  <stephane.chazelas@gmail.com>
+
+				   3/16
+				   ----
+lib/readline/histfile.c
+	- read_history_range: short-circuit and do nothing if the history file
+	  is of 0 size
+	- read_history_range: make sure the buffer is zero-terminated so the
+	  timestamp tests work right for history files of 1 character.  Report
+	  and recommended fix from Denis Martinez <denis.martinez@gmx.com>
+
+lib/readline/complete.c
+	- compute_lcd_of_matches: when trying to compute the common prefix
+	  of a set of matches while performing case-insensitive completion
+	  matching, don't sort the match list unless rl_sort_completion_matches
+	  is non-zero.  Fixes problem reported by Roee Bar <roee@arista.com>
+
+				   3/18
+				   ----
+subst.c
+	- extract_dollar_brace_string: handle process substitution embedded in
+	  a ${...} expansion in the same way as command substitution.  Reported
+	  by D630 <d630@posteo.net>
+
+parse.y
+	- LEX_GTLT: new flag, set by parse_matched_pair when a `<' or '>' is
+	  read
+	- parse_matched_pair: handle an embedded process substitution like an
+	  embedded command substitution if we are parsing an array index or
+	  a dollar-brace expansion.  Reported by D630 <d630@posteo.net>

bashline.c

@@ -3465,6 +3465,7 @@ history_completion_generator (hint_text, state)
 
   while (history_completion_array && history_completion_array[local_index])
     {
+      /* XXX - should this use completion-ignore-case? */
       if (strncmp (text, history_completion_array[local_index++], len) == 0)
 	return (savestring (history_completion_array[local_index - 1]));
     }

doc/bash.1

@@ -5,12 +5,12 @@
 .\"	Case Western Reserve University
 .\"	chet.ramey@case.edu
 .\"
-.\"	Last Change: Sat Mar  4 13:06:51 EST 2017
+.\"	Last Change: Mon Mar 13 12:04:35 EDT 2017
 .\"
 .\" bash_builtins, strip all but Built-Ins section
 .if \n(zZ=1 .ig zZ
 .if \n(zY=1 .ig zY
-.TH BASH 1 "2017 March 4" "GNU Bash 4.4"
+.TH BASH 1 "2017 March 13" "GNU Bash 4.4"
 .\"
 .\" There's some problem with having a `@'
 .\" in a tagged paragraph with the BSD man macros.
@@ -2436,6 +2436,7 @@ The value of this parameter is expanded as with
 and the value is printed before each command
 .B bash
 displays during an execution trace.  The first character of
+the expanded value of
 .SM
 .B PS4
 is replicated multiple times, as necessary, to indicate multiple
@@ -5120,9 +5121,16 @@ when it is ready to read a command, and the secondary prompt
 when it needs more input to complete a command.
 .B Bash
 displays
+.SM
 .B PS0
 after it reads a command but before executing it.
 .B Bash
+displays
+.SM
+.B PS4
+as described above
+before tracing each command when the \fB\-x\fP option is enabled.
+.B Bash
 allows these prompt strings to be customized by inserting a number of
 backslash-escaped special characters that are decoded as follows:
 .RS

doc/bashref.texi

@@ -5458,6 +5458,8 @@ sequences that are expanded before @env{PS1} is displayed.
 
 @item PS2
 The secondary prompt string.  The default value is @samp{> }.
+@env{PS2} is expanded in the same way as @env{PS1} before being
+displayed.
 
 @end vtable
 
@@ -6079,10 +6081,11 @@ The value of this variable is used as the prompt for the
 @code{select} command prompts with @samp{#? }
 
 @item PS4
-The value is the prompt printed before the command line is echoed
-when the @option{-x} option is set (@pxref{The Set Builtin}).
-The first character of @env{PS4} is replicated multiple times, as
-necessary, to indicate multiple levels of indirection.
+The value of this parameter is expanded like @var{PS1}
+and the expanded value is the prompt printed before the command line
+is echoed when the @option{-x} option is set (@pxref{The Set Builtin}).
+The first character of the expanded value is replicated multiple times,
+as necessary, to indicate multiple levels of indirection.
 The default is @samp{+ }.
 
 @item PWD
@@ -6571,7 +6574,10 @@ signals @code{SIGTTIN}, @code{SIGTTOU}, and @code{SIGTSTP}.
 Bash expands and displays @env{PS1} before reading the first line
 of a command, and expands and displays @env{PS2} before reading the
 second and subsequent lines of a multi-line command.
-Bash displays @env{PS0} after it reads a command but before executing it.
+Bash expands and displays @env{PS0} after it reads a command but before
+executing it.
+See @ref{Controlling the Prompt}, for a complete list of prompt
+string escape sequences.
 
 @item
 Bash executes the value of the @env{PROMPT_COMMAND} variable as a command
@@ -7233,7 +7239,8 @@ has a non-null value, then the
 value is executed just as if it had been typed on the command line.
 
 In addition, the following table describes the special characters which
-can appear in the prompt variables @env{PS1} to @env{PS4}:
+can appear in the prompt variables @env{PS0}, @env{PS1}, @env{PS2}, and
+@env{PS4}:
 
 @table @code
 @item \a
@@ -8434,7 +8441,7 @@ If Readline is not enabled, this option has no effect.
 
 @item --enable-prompt-string-decoding
 Turn on the interpretation of a number of backslash-escaped characters
-in the @env{$PS1}, @env{$PS2}, @env{$PS3}, and @env{$PS4} prompt
+in the @env{$PS0}, @env{$PS1}, @env{$PS2}, and @env{$PS4} prompt
 strings.  See @ref{Controlling the Prompt}, for a complete list of prompt
 string escape sequences.
 

doc/version.texi

@@ -2,10 +2,10 @@
 Copyright (C) 1988-2017 Free Software Foundation, Inc.
 @end ignore
 
-@set LASTCHANGE Sat Mar  4 13:06:24 EST 2017
+@set LASTCHANGE Mon Mar 13 11:48:21 EDT 2017
 
 @set EDITION 4.4
 @set VERSION 4.4
 
-@set UPDATED 4 March 2017
+@set UPDATED 13 March 2017
 @set UPDATED-MONTH March 2017

execute_cmd.c

@@ -449,6 +449,16 @@ cleanup_redirects (list)
   dispose_redirects (list);
 }
 
+void
+undo_partial_redirects ()
+{
+  if (redirection_undo_list)
+    {
+      cleanup_redirects (redirection_undo_list);
+      redirection_undo_list = (REDIRECT *)NULL;
+    }
+}
+
 #if 0
 /* Function to unwind_protect the redirections for functions and builtins. */
 static void
@@ -469,6 +479,16 @@ dispose_exec_redirects ()
     }
 }
 
+void
+dispose_partial_redirects ()
+{
+  if (redirection_undo_list)
+    {
+      dispose_redirects (redirection_undo_list);
+      redirection_undo_list = (REDIRECT *)NULL;
+    }
+}
+
 #if defined (JOB_CONTROL)
 /* A function to restore the signal mask to its proper value when the shell
    is interrupted or errors occur while creating a pipeline. */
@@ -728,8 +748,7 @@ execute_command_internal (command, asynchronous, pipe_in, pipe_out,
      redirection.)  */
   if (do_redirections (command->redirects, RX_ACTIVE|RX_UNDOABLE) != 0)
     {
-      cleanup_redirects (redirection_undo_list);
-      redirection_undo_list = (REDIRECT *)NULL;
+      undo_partial_redirects ();
       dispose_exec_redirects ();
 #if defined (PROCESS_SUBSTITUTION)
       if (saved_fifo)
@@ -742,8 +761,7 @@ execute_command_internal (command, asynchronous, pipe_in, pipe_out,
     {
       /* XXX - why copy here? */
       my_undo_list = (REDIRECT *)copy_redirects (redirection_undo_list);
-      dispose_redirects (redirection_undo_list);
-      redirection_undo_list = (REDIRECT *)NULL;
+      dispose_partial_redirects ();
     }
   else
     my_undo_list = (REDIRECT *)NULL;
@@ -752,8 +770,7 @@ execute_command_internal (command, asynchronous, pipe_in, pipe_out,
     {
       /* XXX - why copy here? */
       exec_undo_list = (REDIRECT *)copy_redirects (exec_redirection_undo_list);
-      dispose_redirects (exec_redirection_undo_list);
-      exec_redirection_undo_list = (REDIRECT *)NULL;
+      dispose_exec_redirects ();
     }
   else
     exec_undo_list = (REDIRECT *)NULL;
@@ -1034,10 +1051,7 @@ execute_command_internal (command, asynchronous, pipe_in, pipe_out,
     }
 
   if (my_undo_list)
-    {
-      do_redirections (my_undo_list, RX_ACTIVE);
-      dispose_redirects (my_undo_list);
-    }
+    cleanup_redirects (my_undo_list);
 
   if (exec_undo_list)
     dispose_redirects (exec_undo_list);
@@ -3873,7 +3887,11 @@ execute_null_command (redirects, pipe_in, pipe_out, async)
   REDIRECT *rd;
 
   for (forcefork = 0, rd = redirects; rd; rd = rd->next)
-    forcefork += rd->rflags & REDIR_VARASSIGN;
+    {
+      forcefork += rd->rflags & REDIR_VARASSIGN;
+      /* Safety */
+      forcefork += (rd->redirector.dest == 0 || fd_is_bash_input (rd->redirector.dest)) && (INPUT_REDIRECT (rd->instruction) || TRANSLATE_REDIRECT (rd->instruction) || rd->instruction == r_close_this);
+    }
 
   if (forcefork || pipe_in != NO_PIPE || pipe_out != NO_PIPE || async)
     {
@@ -3890,6 +3908,8 @@ execute_null_command (redirects, pipe_in, pipe_out, async)
 	  coproc_closeall ();
 #endif
 
+	  interactive = 0;			/* XXX */
+
 	  subshell_environment = 0;
 	  if (async)
 	    subshell_environment |= SUBSHELL_ASYNC;
@@ -5041,8 +5061,7 @@ execute_builtin_or_function (words, builtin, var, redirects,
 
   if (do_redirections (redirects, RX_ACTIVE|RX_UNDOABLE) != 0)
     {
-      cleanup_redirects (redirection_undo_list);
-      redirection_undo_list = (REDIRECT *)NULL;
+      undo_partial_redirects ();
       dispose_exec_redirects ();
 #if defined (PROCESS_SUBSTITUTION)
       free (ofifo_list);
@@ -5109,11 +5128,7 @@ execute_builtin_or_function (words, builtin, var, redirects,
       discard_unwind_frame ("saved-redirects");
     }
 
-  if (redirection_undo_list)
-    {
-      cleanup_redirects (redirection_undo_list);
-      redirection_undo_list = (REDIRECT *)NULL;
-    }
+  undo_partial_redirects ();
 
 #if defined (PROCESS_SUBSTITUTION)
   /* Close any FIFOs created by this builtin or function. */

execute_cmd.h

@@ -68,7 +68,10 @@ extern int execute_command __P((COMMAND *));
 extern int execute_command_internal __P((COMMAND *, int, int, int, struct fd_bitmap *));
 extern int shell_execve __P((char *, char **, char **));
 extern void setup_async_signals __P((void));
-extern void dispose_exec_redirects __P ((void));
+
+extern void undo_partial_redirects __P((void));
+extern void dispose_partial_redirects __P((void));
+extern void dispose_exec_redirects __P((void));
 
 extern int execute_shell_function __P((SHELL_VAR *, WORD_LIST *));
 

include/stdc.h

@@ -36,6 +36,16 @@
 #  endif
 #endif
 
+/* New definition to use, moving away from __P since it's part of a reserved
+   namespace */
+#if !defined (PARAMS)
+#  if defined (__STDC__) || defined (__GNUC__) || defined (__cplusplus) || defined (PROTOTYPES)
+#    define PARAMS(protos) protos
+#  else 
+#    define PARAMS(protos) ()
+#  endif
+#endif
+
 /* Fortify, at least, has trouble with this definition */
 #if defined (HAVE_STRINGIZE)
 #  define CPP_STRING(x) #x

input.c

@@ -525,7 +525,7 @@ bufstream_ungetc(c, bp)
      int c;
      BUFFERED_STREAM *bp;
 {
-  if (c == EOF || bp->b_inputp == 0)
+  if (c == EOF || bp == 0 || bp->b_inputp == 0)
     return (EOF);
 
   bp->b_buffer[--bp->b_inputp] = c;
@@ -556,6 +556,9 @@ buffered_getchar ()
 {
   CHECK_TERMSIG;
 
+  if (bash_input.location.buffered_fd < 0 || buffers[bash_input.location.buffered_fd] == 0)
+    return EOF;
+
 #if !defined (DJGPP)
   return (bufstream_getc (buffers[bash_input.location.buffered_fd]));
 #else

lib/readline/complete.c

@@ -1422,7 +1422,8 @@ compute_lcd_of_matches (char **match_list, int matches, const char *text)
 	    }
 
 	  /* sort the list to get consistent answers. */
-	  qsort (match_list+1, matches, sizeof(char *), (QSFUNC *)_rl_qsort_string_compare);
+	  if (rl_sort_completion_matches)
+	    qsort (match_list+1, matches, sizeof(char *), (QSFUNC *)_rl_qsort_string_compare);
 
 	  si = strlen (text);
 	  lx = (si <= low) ? si : low;	/* check shorter of text and matches */
@@ -2644,7 +2645,7 @@ rl_filename_completion_function (const char *text, int state)
    hit the end of the match list, we restore the original unmatched text,
    ring the bell, and reset the counter to zero. */
 int
-rl_old_menu_complete (int count, invoking_key)
+rl_old_menu_complete (int count, int invoking_key)
 {
   rl_compentry_func_t *our_func;
   int matching_filenames, found_quote;
@@ -2947,7 +2948,7 @@ rl_menu_complete (int count, int ignore)
 }
 
 int
-rl_backward_menu_complete (int count, key)
+rl_backward_menu_complete (int count, int key)
 {
   /* Positive arguments to backward-menu-complete translate into negative
      arguments for menu-complete, and vice versa. */

lib/readline/display.c

@@ -2075,7 +2075,7 @@ dumb_update:
 		  _rl_last_c_pos += _rl_col_width (nfd, 0, bytes_to_insert, 1);
 		  if (current_line == 0 && wrap_offset &&
 			displaying_prompt_first_line &&
-			_rl_last_c_pos > wrap_offset &&
+			_rl_last_c_pos >= wrap_offset &&	/* XXX was > */
 			((nfd - new) <= prompt_last_invisible))
 		    {
 		      _rl_last_c_pos -= wrap_offset;

lib/readline/histfile.c

@@ -292,6 +292,9 @@ read_history_range (const char *filename, int from, int to)
       goto error_and_exit;
     }
 
+  if (file_size == 0)
+    return 0;	/* don't waste time if we don't have to */
+
 #ifdef HISTORY_USE_MMAP
   /* We map read/write and private so we can change newlines to NULs without
      affecting the underlying object. */
@@ -338,6 +341,7 @@ read_history_range (const char *filename, int from, int to)
 
   /* Start at beginning of file, work to end. */
   bufend = buffer + chars_read;
+  *bufend = '\0';		/* null-terminate buffer for timestamp checks */
   current_line = 0;
 
   /* Heuristic: the history comment character rarely changes, so assume we

lib/readline/readline.c

@@ -1300,6 +1300,10 @@ bind_arrow_keys_internal (Keymap map)
   rl_bind_keyseq_if_unbound ("\033[1;5D", rl_backward_word);
   rl_bind_keyseq_if_unbound ("\033[3;5~", rl_kill_word);
 
+  /* Key bindings for alt-arrow keys */
+  rl_bind_keyseq_if_unbound ("\033[1;3C", rl_forward_word);
+  rl_bind_keyseq_if_unbound ("\033[1;3D", rl_backward_word);
+
 #if defined (__MINGW32__)
   rl_bind_keyseq_if_unbound ("\340H", rl_get_previous_history);
   rl_bind_keyseq_if_unbound ("\340P", rl_get_next_history);

parse.y

@@ -1,6 +1,6 @@
 /* parse.y - Yacc grammar for bash. */
 
-/* Copyright (C) 1989-2015 Free Software Foundation, Inc.
+/* Copyright (C) 1989-2017 Free Software Foundation, Inc.
 
    This file is part of GNU Bash, the Bourne Again SHell.
 
@@ -116,15 +116,7 @@ typedef void *alias_t;
 extern int extended_glob;
 #endif
 
-extern int eof_encountered;
-extern int no_line_editing, running_under_emacs;
-extern int current_command_number;
-extern int sourcelevel, parse_and_execute_level;
-extern pid_t last_command_subst_pid;
-extern char *dist_version;
-extern int patch_level;
 extern int dump_translatable_strings, dump_po_strings;
-extern sh_builtin_func_t *last_shell_builtin, *this_shell_builtin;
 
 #if !defined (errno)
 extern int errno;
@@ -3335,18 +3327,19 @@ tokword:
 #define P_DOLBRACE	0x0040	/* parsing a ${...} construct */
 
 /* Lexical state while parsing a grouping construct or $(...). */
-#define LEX_WASDOL	0x001
-#define LEX_CKCOMMENT	0x002
-#define LEX_INCOMMENT	0x004
-#define LEX_PASSNEXT	0x008
-#define LEX_RESWDOK	0x010
-#define LEX_CKCASE	0x020
-#define LEX_INCASE	0x040
-#define LEX_INHEREDOC	0x080
-#define LEX_HEREDELIM	0x100		/* reading here-doc delimiter */
-#define LEX_STRIPDOC	0x200		/* <<- strip tabs from here doc delim */
-#define LEX_QUOTEDDOC	0x400		/* here doc with quoted delim */
-#define LEX_INWORD	0x800
+#define LEX_WASDOL	0x0001
+#define LEX_CKCOMMENT	0x0002
+#define LEX_INCOMMENT	0x0004
+#define LEX_PASSNEXT	0x0008
+#define LEX_RESWDOK	0x0010
+#define LEX_CKCASE	0x0020
+#define LEX_INCASE	0x0040
+#define LEX_INHEREDOC	0x0080
+#define LEX_HEREDELIM	0x0100		/* reading here-doc delimiter */
+#define LEX_STRIPDOC	0x0200		/* <<- strip tabs from here doc delim */
+#define LEX_QUOTEDDOC	0x0400		/* here doc with quoted delim */
+#define LEX_INWORD	0x0800
+#define LEX_GTLT	0x1000
 
 #define COMSUB_META(ch)		((ch) == ';' || (ch) == '&' || (ch) == '|')
 
@@ -3377,7 +3370,7 @@ parse_matched_pair (qc, open, close, lenp, flags)
      int open, close;
      int *lenp, flags;
 {
-  int count, ch, tflags;
+  int count, ch, prevch, tflags;
   int nestlen, ttranslen, start_lineno;
   char *ret, *nestret, *ttrans;
   int retind, retsize, rflags;
@@ -3399,8 +3392,10 @@ parse_matched_pair (qc, open, close, lenp, flags)
   retind = 0;
 
   start_lineno = line_number;
+  ch = EOF;		/* just in case */
   while (count)
     {
+      prevch = ch;
       ch = shell_getc (qc != '\'' && (tflags & (LEX_PASSNEXT)) == 0);
 
       if (ch == EOF)
@@ -3594,6 +3589,12 @@ parse_matched_pair (qc, open, close, lenp, flags)
 	    }
 	  else if ((flags & (P_ARRAYSUB|P_DOLBRACE)) && (tflags & LEX_WASDOL) && (ch == '(' || ch == '{' || ch == '['))	/* ) } ] */
 	    goto parse_dollar_word;
+#if defined (PROCESS_SUBSTITUTION)
+	  /* XXX - technically this should only be recognized at the start of
+	     a word */
+	  else if ((flags & (P_ARRAYSUB|P_DOLBRACE)) && (tflags & LEX_GTLT) && (ch == '('))	/* ) */
+	    goto parse_dollar_word;
+#endif
 	}
       /* Parse an old-style command substitution within double quotes as a
 	 single word. */
@@ -3625,6 +3626,12 @@ parse_dollar_word:
 
 	  FREE (nestret);
 	}
+#if defined (PROCESS_SUBSTITUTION)
+      if MBTEST((ch == '<' || ch == '>') && (tflags & LEX_GTLT) == 0)
+	tflags |= LEX_GTLT;
+      else
+	tflags &= ~LEX_GTLT;
+#endif
       if MBTEST(ch == '$' && (tflags & LEX_WASDOL) == 0)
 	tflags |= LEX_WASDOL;
       else

subst.c

@@ -1563,6 +1563,20 @@ extract_dollar_brace_string (string, sindex, quoted, flags)
 	  continue;
 	}
 
+#if defined (PROCESS_SUBSTITUTION)
+      /* Technically this should only work at the start of a word */
+      if ((string[i] == '<' || string[i] == '>') && string[i+1] == LPAREN)
+	{
+	  si = i + 2;
+	  t = extract_process_subst (string, (string[i] == '<' ? "<(" : ">)"), &si, flags|SX_NOALLOC);
+
+	  CHECK_STRING_OVERRUN (i, si, slen, c);
+
+	  i = si + 1;
+	  continue;
+	}
+#endif
+
       /* Pass the contents of double-quoted strings through verbatim. */
       if (c == '"')
 	{
@@ -10281,6 +10295,8 @@ exp_jump_to_top_level (v)
 
   /* Cleanup code goes here. */
   expand_no_split_dollar_star = 0;	/* XXX */
+  if (expanding_redir)
+    undo_partial_redirects ();
   expanding_redir = 0;
   assigning_in_environment = 0;
 

variables.c

@@ -412,7 +412,10 @@ initialize_shell_variables (env, privmode)
 #endif
 	{
 	  ro = 0;
-	  if (posixly_correct && STREQ (name, "SHELLOPTS"))
+	  /* If we processed a command-line option that caused SHELLOPTS to be
+	     set, it may already be set (and read-only) by the time we process
+	     the shell's environment. */
+	  if (/* posixly_correct &&*/ STREQ (name, "SHELLOPTS"))
 	    {
 	      temp_var = find_variable ("SHELLOPTS");
 	      ro = temp_var && readonly_p (temp_var);
@@ -585,8 +588,9 @@ initialize_shell_variables (env, privmode)
 #endif /* HISTORY */
 
 #if defined (READLINE) && defined (STRICT_POSIX)
-  /* POSIXLY_CORRECT will only be 1 here if the shell was compiled
-     -DSTRICT_POSIX */
+  /* POSIXLY_CORRECT will be 1 here if the shell was compiled
+     -DSTRICT_POSIX or if POSIXLY_CORRECT was supplied in the shell's
+     environment */
   if (interactive_shell && posixly_correct && no_line_editing == 0)
     rl_prefer_env_winsize = 1;
 #endif /* READLINE && STRICT_POSIX */