b8c0bc18f0
Reverts this:
commit 0e6f661e23
Date: Fri Feb 15 15:02:15 2008 +0000
ash: handle "A=1 A=2 B=$A; echo $B". closes bug 947.
A different fix from upstream has been imported by previous six commits.
Last seven commits, cumulative:
function old new delta
poplocalvars - 314 +314
mklocal - 288 +288
pushlocalvars - 48 +48
evalcommand 1372 1408 +36
unwindlocalvars - 22 +22
ash_main 1022 1029 +7
setvar 167 172 +5
localvar_stack - 4 +4
setvareq 303 302 -1
evalcase 271 269 -2
subevalvar 1202 1198 -4
localvars 4 - -4
cmdenviron 4 - -4
expandarg 984 973 -11
evalvar 589 574 -15
argstr 1164 1141 -23
dotcmd 335 303 -32
bltinlookup 51 5 -46
varvalue 709 596 -113
evalfun 456 270 -186
localcmd 364 44 -320
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(add/remove: 5/2 grow/shrink: 3/11 up/down: 724/-761) Total: -37 bytes
text data bss dec hex filename
915353 485 6888 922726 e1466 busybox_old
915320 485 6880 922685 e143d busybox_unstripped
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
http://www.opengroup.org/onlinepubs/9699919799/ Open Group Base Specifications Issue 7 http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap01.html Shell & Utilities It says that any of the standard utilities may be implemented as a regular shell built-in. It gives a list of utilities which are usually implemented that way (and some of them can only be implemented as built-ins, like "alias"): alias bg cd command false fc fg getopts jobs kill newgrp pwd read true umask unalias wait http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html Shell Command Language It says that shell must implement special built-ins. Special built-ins differ from regular ones by the fact that variable assignments done on special builtin are *PRESERVED*. That is, VAR=VAL special_builtin; echo $VAR should print VAL. (Another distinction is that an error in special built-in should abort the shell, but this is not such a critical difference, and moreover, at least bash's "set" does not follow this rule, which is even codified in autoconf configure logic now...) List of special builtins: . file : [argument...] break [n] continue [n] eval [argument...] exec [command [argument...]] exit [n] export name[=word]... export -p readonly name[=word]... readonly -p return [n] set [-abCefhmnuvx] [-o option] [argument...] set [+abCefhmnuvx] [+o option] [argument...] set -- [argument...] set -o set +o shift [n] times trap n [condition...] trap [action condition...] unset [-fv] name... In practice, no one uses this obscure feature - none of these builtins gives any special reasons to play such dirty tricks. However. This section also says that *function invocation* should act similar to special built-in. That is, variable assignments done on function invocation should be preserved after function invocation. This is significant: it is not unthinkable to want to run a function with some variables set to special values. But because of the above, it does not work: variable will "leak" out of the function.