new option to auto-close varassign redirs; fixed some new parser error reporting issues

CWRU/CWRU.chlog

@@ -10603,3 +10603,44 @@ builtins/evalstring.c
 	  command, rewind the input string here before returning, instead of
 	  guessing where to rewind it in the caller
 
+				   6/22
+				   ----
+
+redir.c
+	- do_redirection_internal: if VARASSIGN_REDIR_AUTOCLOSE is non-zero,
+	  add a redirect to automatically close {var}<fn and other styles of
+	  varassign redirection. It's zero by default
+
+builtins/shopt.def
+	- varredir_close: new shell option, mirrors the value of
+	  varassign_redir_autoclose. Suggested multiple times by multiple
+	  people
+
+doc/{bash.1,bashref.texi}
+	- varredir_close: document new shell option (the name is tentative)
+
+				   6/24
+				   ----
+
+parse.y
+	- yylex: if read_token returns a value < 0, return YYerror to the
+	  parser
+	- parse_comsub: if the current_token is not shell_eof_token when
+	  yyparse returns, return an error to read_token_word instead of
+	  trying to keep parsing. Fixes interactive-only (?) bug reported by
+	  Koichi Murase <myoga.murase@gmail.com>
+
+parser.h
+	- PST_NOERROR: don't print error messages in yyerror(), just reset
+	  the parser and return
+
+parse.y
+	- yyerror: if parser_state & PST_NOERROR, don't print an error message
+	- xparse_dolparen: if the flags includes SX_COMPLETE, add PST_NOERROR
+	  to parser_state, to inhibit error messages. Fixes bug with adding
+	  lines with incomplete command substitutions to the history list
+	  reported by Koichi Murase <myoga.murase@gmail.com>
+
+subst.c
+	- skip_matched_pair: make sure to pass the SX_COMPLETE flag to
+	  extract_delimited_string

MANIFEST

@@ -1509,6 +1509,7 @@ tests/vredir4.sub	f
 tests/vredir5.sub	f
 tests/vredir6.sub	f
 tests/vredir7.sub	f
+tests/vredir8.sub	f
 tests/misc/dev-tcp.tests	f
 tests/misc/perf-script	f
 tests/misc/perftest	f

builtins/shopt.def

@@ -93,6 +93,7 @@ extern int lastpipe_opt;
 extern int inherit_errexit;
 extern int localvar_inherit;
 extern int localvar_unset;
+extern int varassign_redir_autoclose;
 
 #if defined (EXTENDED_GLOB)
 extern int extended_glob;
@@ -249,6 +250,7 @@ static struct {
 #if defined (SYSLOG_HISTORY) && defined (SYSLOG_SHOPT)
   { "syslog_history", &syslog_history, (shopt_set_func_t *)NULL },
 #endif
+  { "varredir_close", &varassign_redir_autoclose, (shopt_set_func_t *)NULL },
   { "xpg_echo", &xpg_echo, (shopt_set_func_t *)NULL },
   { (char *)0, (int *)0, (shopt_set_func_t *)NULL }
 };
@@ -357,6 +359,7 @@ reset_shopt_options ()
   glob_ignore_case = match_ignore_case = 0;
   print_shift_error = 0;
   source_uses_path = promptvars = 1;
+  varassign_redir_autoclose = 0;
 
 #if defined (JOB_CONTROL)
   check_jobs_at_exit = 0;

doc/bash.1

@@ -589,12 +589,12 @@ The
 variable may be used to specify the format of
 the time information.
 .PP
-Each command in a pipeline is executed as a separate process (i.e., in a
-subshell).
+Each command in a pipeline is executed in a \fIsubshell\fP, which is a
+separate process.
 See
 .SM
 \fBCOMMAND EXECUTION ENVIRONMENT\fP
-for a description of a subshell environment.
+for a description of subshells and a subshell environment.
 If the \fBlastpipe\fP option is enabled using the \fBshopt\fP builtin
 (see the description of \fBshopt\fP below),
 the last element of a pipeline may be run by the shell process
@@ -673,10 +673,10 @@ the rest of the command by one or more newlines, and may be followed by a
 newline in place of a semicolon.
 .TP
 (\fIlist\fP)
-\fIlist\fP is executed in a subshell environment (see
+\fIlist\fP is executed in a subshell (see
 .SM
 \fBCOMMAND EXECUTION ENVIRONMENT\fP
-below).
+below for a description of a subshell environment).
 Variable assignments and builtin
 commands that affect the shell's environment do not remain in effect
 after the command completes.  The return status is the exit status of
@@ -1278,10 +1278,7 @@ is evaluated as an arithmetic expression even if the $((...)) expansion is
 not used (see
 .B "Arithmetic Expansion"
 below).
-Word splitting is not performed, with the exception
-of \fB"$@"\fP as explained below under
-.BR "Special Parameters" .
-Pathname expansion is not performed.
+Word splitting and pathname expansion are not performed.
 Assignment statements may also appear as arguments to the
 .BR alias ,
 .BR declare ,
@@ -1435,7 +1432,7 @@ builtin command, or those set by the shell itself
 option).
 .TP
 .B $
-Expands to the process ID of the shell.  In a () subshell, it
+Expands to the process ID of the shell. In a subshell, it
 expands to the process ID of the current shell, not the
 subshell.
 .TP
@@ -3950,7 +3947,8 @@ by {\fIvarname\fP}, the value of \fIvarname\fP defines the file
 descriptor to close.
 If {\fIvarname\fP} is supplied, the redirection persists beyond
 the scope of the command, allowing the shell programmer to manage
-the file descriptor himself.
+the file descriptor's lifetime manually.
+The \fBvarredir_close\fP shell option manages this behavior.
 .PP
 In the following descriptions, if the file descriptor number is
 omitted, and the first character of the redirection operator is
@@ -4503,7 +4501,8 @@ or
 will list the function names only
 (and optionally the source file and line number, if the \fBextdebug\fP
 shell option is enabled).
-Functions may be exported so that subshells
+Functions may be exported so that child shell processes
+(those created when executing a separate shell invocation)
 automatically have them defined with the
 .B \-f
 option to the
@@ -4892,8 +4891,9 @@ to the command are set to the arguments given, if any.
 If this execution fails because the file is not in executable
 format, and the file is not a directory, it is assumed to be
 a \fIshell script\fP, a file
-containing shell commands.  A subshell is spawned to execute
-it.  This subshell reinitializes itself, so
+containing shell commands, and the shell creates a 
+to execute it.
+This subshell reinitializes itself, so
 that the effect is as if a new shell had been invoked
 to handle the script, with the exception that the locations of
 commands remembered by the parent (see
@@ -4949,8 +4949,8 @@ of \fB$$\fP, and the value of
 When a simple command other than a builtin or shell function
 is to be executed, it
 is invoked in a separate execution environment that consists of
-the following.  Unless otherwise noted, the values are inherited
-from the shell.
+the following.
+Unless otherwise noted, the values are inherited from the shell.
 .if n .sp 1
 .IP \(bu
 the shell's open files, plus any modifications and additions specified
@@ -4969,6 +4969,8 @@ shell's parent, and traps ignored by the shell are ignored
 A command invoked in this separate environment cannot affect the
 shell's execution environment.
 .PP
+A \fIsubshell\fP is a copy of the shell process.
+.PP
 Command substitution, commands grouped with parentheses,
 and asynchronous commands are invoked in a
 subshell environment that is a duplicate of the shell environment,
@@ -10398,6 +10400,13 @@ If set, the
 to find the directory containing the file supplied as an argument.
 This option is enabled by default.
 .TP 8
+.B varredir_close
+If set, the shell automatically closes file descriptors assigned using the
+\fI{varname}\fP redirection syntax (see
+.SM
+.B REDIRECTION
+above) instead of leaving them open when the command completes.
+.TP 8
 .B xpg_echo
 If set, the \fBecho\fP builtin expands backslash-escape sequences
 by default.

doc/bashref.info

@@ -703,8 +703,8 @@ information.
    If the pipeline is not executed asynchronously (*note Lists::), the
 shell waits for all commands in the pipeline to complete.
 
-   Each command in a pipeline is executed in its own subshell, which is
-a separate process (*note Command Execution Environment::).  If the
+   Each command in a pipeline is executed in its own "subshell", which
+is a separate process (*note Command Execution Environment::).  If the
 'lastpipe' option is enabled using the 'shopt' builtin (*note The Shopt
 Builtin::), the last element of a pipeline may be run by the shell
 process when job control is not active.
@@ -1176,9 +1176,9 @@ list may be redirected to a single stream.
 '()'
           ( LIST )
 
-     Placing a list of commands between parentheses causes a subshell
-     environment to be created (*note Command Execution Environment::),
-     and each of the commands in LIST to be executed in that subshell.
+     Placing a list of commands between parentheses forces the shell to
+     create a subshell (*note Command Execution Environment::), and each
+     of the commands in LIST is executed in that subshell environment.
      Since the LIST is executed in a subshell, variable assignments do
      not remain in effect after the subshell completes.
 
@@ -1423,7 +1423,8 @@ been shadowed will become visible.
 the 'declare' ('typeset') builtin command (*note Bash Builtins::).  The
 '-F' option to 'declare' or 'typeset' will list the function names only
 (and optionally the source file and line number, if the 'extdebug' shell
-option is enabled).  Functions may be exported so that subshells
+option is enabled).  Functions may be exported so that child shell
+processes (those created when executing a separate shell invocation)
 automatically have them defined with the '-f' option to the 'export'
 builtin (*note Bourne Shell Builtins::).
 
@@ -1584,9 +1585,8 @@ only be referenced; assignment to them is not allowed.
      shell itself (such as the '-i' option).
 
 '$'
-     ($$) Expands to the process ID of the shell.  In a '()' subshell,
-     it expands to the process ID of the invoking shell, not the
-     subshell.
+     ($$) Expands to the process ID of the shell.  In a subshell, it
+     expands to the process ID of the invoking shell, not the subshell.
 
 '!'
      ($!)  Expands to the process ID of the job most recently placed
@@ -2382,6 +2382,14 @@ the following sub-patterns:
 '!(PATTERN-LIST)'
      Matches anything except one of the given patterns.
 
+   When matching filenames, the 'dotglob' shell option determines the
+set of filenames that are tested: when 'dotglob' is enabled, the set of
+filenames includes all files beginning with '.', but the filenames '.'
+and '..' must be matched by a pattern or sub-pattern that begins with a
+dot; when it is disabled, the set does not include any filenames
+beginning with "."  unless the pattern or sub-pattern begins with a '.'.
+As above, '.' only has a special meaning when matching filenames.
+
    Complicated extended pattern matching against long strings is slow,
 especially when the patterns contain alternations and the strings
 contain multiple matches.  Using separate matches against shorter
@@ -2421,7 +2429,8 @@ file descriptor greater than 10 and assign it to {VARNAME}.  If >&- or
 <&- is preceded by {VARNAME}, the value of VARNAME defines the file
 descriptor to close.  If {VARNAME} is supplied, the redirection persists
 beyond the scope of the command, allowing the shell programmer to manage
-the file descriptor's lifetime manually.
+the file descriptor's lifetime manually.  The 'varredir_close' shell
+option manages this behavior (*note The Shopt Builtin::).
 
    In the following descriptions, if the file descriptor number is
 omitted, and the first character of the redirection operator is '<', the
@@ -2805,6 +2814,8 @@ inherited from the shell.
    A command invoked in this separate environment cannot affect the
 shell's execution environment.
 
+   A "subshell" is a copy of the shell process.
+
    Command substitution, commands grouped with parentheses, and
 asynchronous commands are invoked in a subshell environment that is a
 duplicate of the shell environment, except that traps caught by the
@@ -2960,8 +2971,8 @@ parameters are unset.
 
    A shell script may be made executable by using the 'chmod' command to
 turn on the execute bit.  When Bash finds such a file while searching
-the '$PATH' for a command, it spawns a subshell to execute it.  In other
-words, executing
+the '$PATH' for a command, it creates a subshell to execute it.  In
+other words, executing
      filename ARGUMENTS
 is equivalent to executing
      bash filename ARGUMENTS
@@ -4871,6 +4882,12 @@ This builtin allows you to change additional shell optional behavior.
           find the directory containing the file supplied as an
           argument.  This option is enabled by default.
 
+     'varredir_close'
+          If set, the shell automatically closes file descriptors
+          assigned using the '{varname}' redirection syntax (*note
+          Redirections::) instead of leaving them open when the command
+          completes.
+
      'xpg_echo'
           If set, the 'echo' builtin expands backslash-escape sequences
           by default.
@@ -11590,21 +11607,21 @@ D.3 Parameter and Variable Index
 [index]
 * Menu:
 
-* !:                                     Special Parameters.  (line  56)
+* !:                                     Special Parameters.  (line  55)
 * #:                                     Special Parameters.  (line  39)
 * $:                                     Special Parameters.  (line  51)
-* $!:                                    Special Parameters.  (line  57)
+* $!:                                    Special Parameters.  (line  56)
 * $#:                                    Special Parameters.  (line  40)
 * $$:                                    Special Parameters.  (line  52)
 * $*:                                    Special Parameters.  (line  10)
 * $-:                                    Special Parameters.  (line  47)
-* $0:                                    Special Parameters.  (line  62)
+* $0:                                    Special Parameters.  (line  61)
 * $?:                                    Special Parameters.  (line  43)
 * $@:                                    Special Parameters.  (line  23)
 * $_:                                    Bash Variables.      (line  14)
 * *:                                     Special Parameters.  (line   9)
 * -:                                     Special Parameters.  (line  46)
-* 0:                                     Special Parameters.  (line  61)
+* 0:                                     Special Parameters.  (line  60)
 * ?:                                     Special Parameters.  (line  42)
 * @:                                     Special Parameters.  (line  22)
 * _:                                     Bash Variables.      (line  13)
@@ -12215,118 +12232,118 @@ Node: Shell Commands23773
 Node: Reserved Words24711
 Node: Simple Commands25467
 Node: Pipelines26121
-Node: Lists29078
-Node: Compound Commands30873
-Node: Looping Constructs31885
-Node: Conditional Constructs34380
-Node: Command Grouping48670
-Node: Coprocesses50145
-Node: GNU Parallel52808
-Node: Shell Functions53725
-Node: Shell Parameters60945
-Node: Positional Parameters65396
-Node: Special Parameters66298
-Node: Shell Expansions69522
-Node: Brace Expansion71649
-Node: Tilde Expansion74383
-Node: Shell Parameter Expansion77004
-Node: Command Substitution92133
-Node: Arithmetic Expansion93488
-Node: Process Substitution94420
-Node: Word Splitting95540
-Node: Filename Expansion97484
-Node: Pattern Matching100084
-Node: Quote Removal104202
-Node: Redirections104497
-Node: Executing Commands114071
-Node: Simple Command Expansion114741
-Node: Command Search and Execution116695
-Node: Command Execution Environment119073
-Node: Environment122059
-Node: Exit Status123722
-Node: Signals125506
-Node: Shell Scripts127473
-Node: Shell Builtin Commands130485
-Node: Bourne Shell Builtins132523
-Node: Bash Builtins153984
-Node: Modifying Shell Behavior184498
-Node: The Set Builtin184843
-Node: The Shopt Builtin195256
-Node: Special Builtins210217
-Node: Shell Variables211196
-Node: Bourne Shell Variables211633
-Node: Bash Variables213737
-Node: Bash Features246552
-Node: Invoking Bash247565
-Node: Bash Startup Files253578
-Node: Interactive Shells258681
-Node: What is an Interactive Shell?259091
-Node: Is this Shell Interactive?259740
-Node: Interactive Shell Behavior260555
-Node: Bash Conditional Expressions264068
-Node: Shell Arithmetic268710
-Node: Aliases271654
-Node: Arrays274267
-Node: The Directory Stack280276
-Node: Directory Stack Builtins281060
-Node: Controlling the Prompt285320
-Node: The Restricted Shell288285
-Node: Bash POSIX Mode290882
-Node: Shell Compatibility Mode302155
-Node: Job Control308811
-Node: Job Control Basics309271
-Node: Job Control Builtins314273
-Node: Job Control Variables319673
-Node: Command Line Editing320829
-Node: Introduction and Notation322500
-Node: Readline Interaction324123
-Node: Readline Bare Essentials325314
-Node: Readline Movement Commands327097
-Node: Readline Killing Commands328057
-Node: Readline Arguments329975
-Node: Searching331019
-Node: Readline Init File333205
-Node: Readline Init File Syntax334466
-Node: Conditional Init Constructs355746
-Node: Sample Init File359942
-Node: Bindable Readline Commands363066
-Node: Commands For Moving364270
-Node: Commands For History366321
-Node: Commands For Text371315
-Node: Commands For Killing374964
-Node: Numeric Arguments377997
-Node: Commands For Completion379136
-Node: Keyboard Macros383327
-Node: Miscellaneous Commands384014
-Node: Readline vi Mode389953
-Node: Programmable Completion390860
-Node: Programmable Completion Builtins398640
-Node: A Programmable Completion Example409335
-Node: Using History Interactively414582
-Node: Bash History Facilities415266
-Node: Bash History Builtins418271
-Node: History Interaction423279
-Node: Event Designators426899
-Node: Word Designators428253
-Node: Modifiers430013
-Node: Installing Bash431824
-Node: Basic Installation432961
-Node: Compilers and Options436219
-Node: Compiling For Multiple Architectures436960
-Node: Installation Names438653
-Node: Specifying the System Type439471
-Node: Sharing Defaults440187
-Node: Operation Controls440860
-Node: Optional Features441818
-Node: Reporting Bugs452618
-Node: Major Differences From The Bourne Shell453893
-Node: GNU Free Documentation License470743
-Node: Indexes495920
-Node: Builtin Index496374
-Node: Reserved Word Index503201
-Node: Variable Index505649
-Node: Function Index522141
-Node: Concept Index535925
+Node: Lists29080
+Node: Compound Commands30875
+Node: Looping Constructs31887
+Node: Conditional Constructs34382
+Node: Command Grouping48672
+Node: Coprocesses50150
+Node: GNU Parallel52813
+Node: Shell Functions53730
+Node: Shell Parameters61021
+Node: Positional Parameters65472
+Node: Special Parameters66374
+Node: Shell Expansions69588
+Node: Brace Expansion71715
+Node: Tilde Expansion74449
+Node: Shell Parameter Expansion77070
+Node: Command Substitution92199
+Node: Arithmetic Expansion93554
+Node: Process Substitution94486
+Node: Word Splitting95606
+Node: Filename Expansion97550
+Node: Pattern Matching100150
+Node: Quote Removal104758
+Node: Redirections105053
+Node: Executing Commands114713
+Node: Simple Command Expansion115383
+Node: Command Search and Execution117337
+Node: Command Execution Environment119715
+Node: Environment122750
+Node: Exit Status124413
+Node: Signals126197
+Node: Shell Scripts128164
+Node: Shell Builtin Commands131177
+Node: Bourne Shell Builtins133215
+Node: Bash Builtins154676
+Node: Modifying Shell Behavior185190
+Node: The Set Builtin185535
+Node: The Shopt Builtin195948
+Node: Special Builtins211158
+Node: Shell Variables212137
+Node: Bourne Shell Variables212574
+Node: Bash Variables214678
+Node: Bash Features247493
+Node: Invoking Bash248506
+Node: Bash Startup Files254519
+Node: Interactive Shells259622
+Node: What is an Interactive Shell?260032
+Node: Is this Shell Interactive?260681
+Node: Interactive Shell Behavior261496
+Node: Bash Conditional Expressions265009
+Node: Shell Arithmetic269651
+Node: Aliases272595
+Node: Arrays275208
+Node: The Directory Stack281217
+Node: Directory Stack Builtins282001
+Node: Controlling the Prompt286261
+Node: The Restricted Shell289226
+Node: Bash POSIX Mode291823
+Node: Shell Compatibility Mode303096
+Node: Job Control309752
+Node: Job Control Basics310212
+Node: Job Control Builtins315214
+Node: Job Control Variables320614
+Node: Command Line Editing321770
+Node: Introduction and Notation323441
+Node: Readline Interaction325064
+Node: Readline Bare Essentials326255
+Node: Readline Movement Commands328038
+Node: Readline Killing Commands328998
+Node: Readline Arguments330916
+Node: Searching331960
+Node: Readline Init File334146
+Node: Readline Init File Syntax335407
+Node: Conditional Init Constructs356687
+Node: Sample Init File360883
+Node: Bindable Readline Commands364007
+Node: Commands For Moving365211
+Node: Commands For History367262
+Node: Commands For Text372256
+Node: Commands For Killing375905
+Node: Numeric Arguments378938
+Node: Commands For Completion380077
+Node: Keyboard Macros384268
+Node: Miscellaneous Commands384955
+Node: Readline vi Mode390894
+Node: Programmable Completion391801
+Node: Programmable Completion Builtins399581
+Node: A Programmable Completion Example410276
+Node: Using History Interactively415523
+Node: Bash History Facilities416207
+Node: Bash History Builtins419212
+Node: History Interaction424220
+Node: Event Designators427840
+Node: Word Designators429194
+Node: Modifiers430954
+Node: Installing Bash432765
+Node: Basic Installation433902
+Node: Compilers and Options437160
+Node: Compiling For Multiple Architectures437901
+Node: Installation Names439594
+Node: Specifying the System Type440412
+Node: Sharing Defaults441128
+Node: Operation Controls441801
+Node: Optional Features442759
+Node: Reporting Bugs453559
+Node: Major Differences From The Bourne Shell454834
+Node: GNU Free Documentation License471684
+Node: Indexes496861
+Node: Builtin Index497315
+Node: Reserved Word Index504142
+Node: Variable Index506590
+Node: Function Index523082
+Node: Concept Index536866
 
 End Tag Table
 

doc/bashref.texi

@@ -798,7 +798,7 @@ the time information.
 If the pipeline is not executed asynchronously (@pxref{Lists}), the
 shell waits for all commands in the pipeline to complete.
 
-Each command in a pipeline is executed in its own subshell, which is a
+Each command in a pipeline is executed in its own @dfn{subshell}, which is a
 separate process (@pxref{Command Execution Environment}).
 If the @code{lastpipe} option is enabled using the @code{shopt} builtin
 (@pxref{The Shopt Builtin}),
@@ -1368,11 +1368,11 @@ commands in the list may be redirected to a single stream.
 ( @var{list} )
 @end example
 
-Placing a list of commands between parentheses causes a subshell
-environment to be created (@pxref{Command Execution Environment}), and each
-of the commands in @var{list} to be executed in that subshell.  Since the
-@var{list} is executed in a subshell, variable assignments do not remain in
-effect after the subshell completes. 
+Placing a list of commands between parentheses forces the shell to create
+a subshell (@pxref{Command Execution Environment}), and each
+of the commands in @var{list} is executed in that subshell environment.
+Since the @var{list} is executed in a subshell, variable assignments do not
+remain in effect after the subshell completes. 
 
 @item @{@}
 @rwindex @{
@@ -1665,7 +1665,8 @@ The @option{-F} option to @code{declare} or @code{typeset}
 will list the function names only
 (and optionally the source file and line number, if the @code{extdebug}
 shell option is enabled).
-Functions may be exported so that subshells
+Functions may be exported so that child shell processes
+(those created when executing a separate shell invocation)
 automatically have them defined with the
 @option{-f} option to the @code{export} builtin
 (@pxref{Bourne Shell Builtins}).
@@ -1712,9 +1713,7 @@ If the variable has its @code{integer}
 attribute set, then @var{value} 
 is evaluated as an arithmetic expression even if the @code{$((@dots{}))}
 expansion is not used (@pxref{Arithmetic Expansion}).
-Word splitting is not performed, with the exception
-of @code{"$@@"} as explained below.
-Filename expansion is not performed.
+Word splitting and filename expansion are not performed.
 Assignment statements may also appear as arguments to the
 @code{alias}, 
 @code{declare}, @code{typeset}, @code{export}, @code{readonly},
@@ -1863,7 +1862,7 @@ builtin command, or those set by the shell itself
 
 @item $
 @vindex $$
-($$) Expands to the process @sc{id} of the shell.  In a @code{()} subshell, it
+($$) Expands to the process @sc{id} of the shell.  In a subshell, it
 expands to the process @sc{id} of the invoking shell, not the subshell.
 
 @item !
@@ -2844,6 +2843,8 @@ descriptor to close.
 If @{@var{varname}@} is supplied, the redirection persists beyond
 the scope of the command, allowing the shell programmer to manage
 the file descriptor's lifetime manually.
+The @code{varredir_close} shell option manages this behavior
+(@pxref{The Shopt Builtin}).
 
 In the following descriptions, if the file descriptor number is
 omitted, and the first character of the redirection operator is
@@ -3306,6 +3307,8 @@ shell's parent, and traps ignored by the shell are ignored
 A command invoked in this separate environment cannot affect the
 shell's execution environment.
 
+A @dfn{subshell} is a copy of the shell process.
+
 Command substitution, commands grouped with parentheses,
 and asynchronous commands are invoked in a
 subshell environment that is a duplicate of the shell environment,
@@ -3471,7 +3474,7 @@ are unset.
 
 A shell script may be made executable by using the @code{chmod} command
 to turn on the execute bit.  When Bash finds such a file while
-searching the @env{$PATH} for a command, it spawns a subshell to
+searching the @env{$PATH} for a command, it creates a subshell to
 execute it.  In other words, executing
 @example
 filename @var{arguments}
@@ -5674,6 +5677,11 @@ If set, the @code{.} (@code{source}) builtin uses the value of @env{PATH}
 to find the directory containing the file supplied as an argument.
 This option is enabled by default.
 
+@item varredir_close
+If set, the shell automatically closes file descriptors assigned using the
+@code{@{varname@}} redirection syntax (@pxref{Redirections}) instead of
+leaving them open when the command completes.
+
 @item xpg_echo
 If set, the @code{echo} builtin expands backslash-escape sequences
 by default.

parse.y

@@ -2900,6 +2900,9 @@ yylex ()
       return (current_token);
     }
 
+  if (current_token < 0)
+    current_token = YYerror;
+
   return (current_token);
 }
 
@@ -4085,10 +4088,11 @@ itrace("parse_comsub: need_here_doc = %d after yyparse()?", need_here_doc);
     }
 
   if (current_token != shell_eof_token)
-{
+    {
 itrace("current_token (%d) != shell_eof_token (%c)", current_token, shell_eof_token);
-    token_to_read = current_token;
-}
+      token_to_read = current_token;
+      return (&matched_pair_error);
+    }
 
   restore_parser_state (&ps);
 
@@ -4161,6 +4165,8 @@ xparse_dolparen (base, string, indp, flags)
   /*(*/
   parser_state |= PST_CMDSUBST|PST_EOFTOKEN;	/* allow instant ')' */ /*(*/
   shell_eof_token = ')';
+  if (flags & SX_COMPLETE)
+    parser_state |= PST_NOERROR;
 
   token_to_read = DOLPAREN;			/* let's trick the parser */
 
@@ -4219,7 +4225,8 @@ xparse_dolparen (base, string, indp, flags)
   if (base[*indp] != ')' && (flags & SX_NOLONGJMP) == 0)
     {
       /*(*/
-      parser_error (start_lineno, _("unexpected EOF while looking for matching `%c'"), ')');
+      if ((flags & SX_NOERROR) == 0)
+	parser_error (start_lineno, _("unexpected EOF while looking for matching `%c'"), ')');
       jump_to_top_level (DISCARD);
     }
 
@@ -5878,7 +5885,8 @@ int
 yyerror (msg)
      const char *msg;
 {
-  report_syntax_error ((char *)NULL);
+  if ((parser_state & PST_NOERROR) == 0)
+    report_syntax_error ((char *)NULL);
   reset_parser ();
   return (0);
 }

parser.h

@@ -49,6 +49,7 @@
 #define PST_COMMENT	0x100000	/* parsing a shell comment; used by aliases */
 #define PST_ENDALIAS	0x200000	/* just finished expanding and consuming an alias */
 #define PST_NOEXPAND	0x400000	/* don't expand anything in read_token_word; for command substitution */
+#define PST_NOERROR	0x800000	/* don't print error messages in yyerror */
 
 /* Definition of the delimiter stack.  Needed by parse.y and bashhist.c. */
 struct dstack {

patchlevel.h

@@ -25,6 +25,6 @@
    regexp `^#define[ 	]*PATCHLEVEL', since that's what support/mkversion.sh
    looks for to find the patch level (for the sccs version string). */
 
-#define PATCHLEVEL 4
+#define PATCHLEVEL 8
 
 #endif /* _PATCHLEVEL_H_ */

redir.c

@@ -1,6 +1,6 @@
 /* redir.c -- Functions to perform input and output redirection. */
 
-/* Copyright (C) 1997-2020 Free Software Foundation, Inc.
+/* Copyright (C) 1997-2021 Free Software Foundation, Inc.
 
    This file is part of GNU Bash, the Bourne Again SHell.
 
@@ -88,6 +88,7 @@ extern int errno;
 #define SHELL_FD_BASE	10
 
 int expanding_redir;
+int varassign_redir_autoclose = 0;
 
 extern REDIRECT *redirection_undo_list;
 extern REDIRECT *exec_redirection_undo_list;
@@ -949,10 +950,15 @@ do_redirection_internal (redirect, flags, fnp)
 	      REDIRECTION_ERROR (redirector, r, fd);
 	    }
 
-	  if ((flags & RX_UNDOABLE) && (redirect->rflags & REDIR_VARASSIGN) == 0)
+	  if ((flags & RX_UNDOABLE) && ((redirect->rflags & REDIR_VARASSIGN) == 0 || varassign_redir_autoclose))
 	    {
-	      /* Only setup to undo it if the thing to undo is active. */
-	      if ((fd != redirector) && (fcntl (redirector, F_GETFD, 0) != -1))
+	      /* Only setup to undo it if the thing to undo is active. We want
+		 to autoclose if we are doing a varassign redirection and the
+		 varredir_close shell option is set, and we can't test
+		 redirector in this case since we just assigned it above. */		 
+	      if (fd != redirector && (redirect->rflags & REDIR_VARASSIGN) && varassign_redir_autoclose)
+		r = add_undo_close_redirect (redirector);	      
+	      else if ((fd != redirector) && (fcntl (redirector, F_GETFD, 0) != -1))
 		r = add_undo_redirect (redirector, ri, -1);
 	      else
 		r = add_undo_close_redirect (redirector);
@@ -1066,10 +1072,14 @@ do_redirection_internal (redirect, flags, fnp)
 
 	  if (flags & RX_ACTIVE)
 	    {
-	      if ((flags & RX_UNDOABLE) && (redirect->rflags & REDIR_VARASSIGN) == 0)
+	      if ((flags & RX_UNDOABLE) && ((redirect->rflags & REDIR_VARASSIGN) == 0 || varassign_redir_autoclose))
 	        {
-		  /* Only setup to undo it if the thing to undo is active. */
-		  if ((fd != redirector) && (fcntl (redirector, F_GETFD, 0) != -1))
+		  /* Only setup to undo it if the thing to undo is active.
+		     Close if the right option is set and we are doing a
+		     varassign redirection. */
+		  if (fd != redirector && (redirect->rflags & REDIR_VARASSIGN) && varassign_redir_autoclose)
+		    r = add_undo_close_redirect (redirector);	      
+		  else if ((fd != redirector) && (fcntl (redirector, F_GETFD, 0) != -1))
 		    r = add_undo_redirect (redirector, ri, -1);
 		  else
 		    r = add_undo_close_redirect (redirector);
@@ -1127,10 +1137,14 @@ do_redirection_internal (redirect, flags, fnp)
 
       if ((flags & RX_ACTIVE) && (redir_fd != redirector))
 	{
-	  if ((flags & RX_UNDOABLE) && (redirect->rflags & REDIR_VARASSIGN) == 0)
+	  if ((flags & RX_UNDOABLE) && ((redirect->rflags & REDIR_VARASSIGN) == 0 || varassign_redir_autoclose))
 	    {
-	      /* Only setup to undo it if the thing to undo is active. */
-	      if (fcntl (redirector, F_GETFD, 0) != -1)
+	      /* Only setup to undo it if the thing to undo is active.
+		 Close if the right option is set and we are doing a
+		 varassign redirection. */
+	      if ((redirect->rflags & REDIR_VARASSIGN) && varassign_redir_autoclose)
+		r = add_undo_close_redirect (redirector);	      
+	      else if (fcntl (redirector, F_GETFD, 0) != -1)
 		r = add_undo_redirect (redirector, ri, redir_fd);
 	      else
 		r = add_undo_close_redirect (redirector);
@@ -1219,7 +1233,6 @@ do_redirection_internal (redirect, flags, fnp)
 	    }
 
 	  r = 0;
-	  /* XXX - only if REDIR_VARASSIGN not set? */
 	  if (flags & RX_UNDOABLE)
 	    {
 	      if (fcntl (redirector, F_GETFD, 0) != -1)

subst.c

@@ -1961,7 +1961,7 @@ skip_to_delim (string, start, delims, flags)
 	    CQ_RETURN(si);
 
 	  if (string[i+1] == LPAREN)
-	    temp = extract_delimited_string (string, &si, "$(", "(", ")", SX_NOALLOC|SX_COMMAND); /* ) */
+	    temp = extract_delimited_string (string, &si, "$(", "(", ")", SX_NOALLOC|SX_COMMAND|completeflag); /* ) */
 	  else
 	    temp = extract_dollar_brace_string (string, &si, 0, SX_NOALLOC);
 	  CHECK_STRING_OVERRUN (i, si, slen, c);

subst.h

@@ -1,6 +1,6 @@
 /* subst.h -- Names of externally visible functions in subst.c. */
 
-/* Copyright (C) 1993-2017 Free Software Foundation, Inc.
+/* Copyright (C) 1993-2021 Free Software Foundation, Inc.
 
    This file is part of GNU Bash, the Bourne Again SHell.
 
@@ -71,6 +71,7 @@
 #define SX_WORD		0x0200	/* extracting word in ${param op word} */
 #define SX_COMPLETE	0x0400	/* extracting word for completion */
 #define SX_STRIPDQ	0x0800	/* strip double quotes when extracting double-quoted string */
+#define SX_NOERROR	0x1000	/* don't print parser error messages */
 
 /* Remove backslashes which are quoting backquotes from STRING.  Modifies
    STRING, and returns a pointer to it. */
@@ -314,6 +315,7 @@ extern char *cond_expand_word PARAMS((WORD_DESC *, int));
 #define SD_COMPLETE	0x100	/* skip_to_delim during completion */
 #define SD_HISTEXP	0x200	/* skip_to_delim during history expansion */
 #define SD_ARITHEXP	0x400	/* skip_to_delim during arithmetic expansion */
+#define SD_NOERROR	0x800	/* don't print error messages */
 
 extern int skip_to_delim PARAMS((char *, int, char *, int));
 

tests/comsub-eof.right

@@ -5,7 +5,6 @@ hi
 hi
 ./comsub-eof3.sub: line 4: warning: here-document at line 1 delimited by end-of-file (wanted `EOF')
 ./comsub-eof3.sub: line 5: unexpected EOF while looking for matching `)'
-./comsub-eof3.sub: line 5: unexpected EOF while looking for matching `)'
 ./comsub-eof4.sub: line 3: warning: here-document at line 1 delimited by end-of-file (wanted `EOF')
 contents
 ./comsub-eof5.sub: line 4: warning: here-document at line 2 delimited by end-of-file (wanted `)')

tests/posixexp.right

@@ -286,4 +286,3 @@ argv[1] = <"A">
 argv[1] = <A>
 argv[1] = <A>
 ./posixexp.tests: line 97: unexpected EOF while looking for matching `}'
-./posixexp.tests: line 98: syntax error: unexpected end of file

tests/shopt.right

@@ -53,6 +53,7 @@ shopt -s promptvars
 shopt -u restricted_shell
 shopt -u shift_verbose
 shopt -s sourcepath
+shopt -u varredir_close
 shopt -u xpg_echo
 --
 shopt -u huponexit
@@ -112,6 +113,7 @@ shopt -u nullglob
 shopt -u progcomp_alias
 shopt -u restricted_shell
 shopt -u shift_verbose
+shopt -u varredir_close
 shopt -u xpg_echo
 --
 autocd         	off
@@ -154,6 +156,7 @@ nullglob       	off
 progcomp_alias 	off
 restricted_shell	off
 shift_verbose  	off
+varredir_close 	off
 xpg_echo       	off
 --
 set +o allexport

tests/vredir.right

@@ -98,3 +98,4 @@ swizzle ()
     exec {stdin}<&${fd[0]}-;
     exec {stdout}>&${fd[1]}-
 }
+./vredir8.sub: line 12: $fd: Bad file descriptor

tests/vredir.tests

@@ -57,5 +57,6 @@ ${THIS_SH} ./vredir5.sub
 ${THIS_SH} ./vredir6.sub
 
 ${THIS_SH} ./vredir7.sub
+${THIS_SH} ./vredir8.sub
 
 exit 0

tests/vredir8.sub

@@ -0,0 +1,13 @@
+# test varredir_close
+
+: {fd}<>/dev/null
+
+echo redir 1 >&$fd
+exec {fd}>&-
+
+shopt -s varredir_close
+
+: {fd}<>/dev/tty
+
+echo redir 2 >&$fd
+exec {fd}>&-