[git commit] ash: eval: Variable assignments on functions are no longer persistent
Denys Vlasenko
vda.linux at googlemail.com
Sun Aug 5 09:14:11 UTC 2018
commit: https://git.busybox.net/busybox/commit/?id=9abf53beb48b40e98d50fd35f445d6474af3a494
branch: https://git.busybox.net/busybox/commit/?id=refs/heads/master
Upstream commit:
Date: Wed, 4 Apr 2018 17:54:01 +0800
eval: Variable assignments on functions are no longer persistent
Dirk Fieldhouse <fieldhouse at gmx.net> wrote:
> In POSIX.1-2017 ("simultaneously IEEE Std 1003.1â„¢-2017 and The Open
> Group Technical Standard Base Specifications, Issue 7")
> <http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_09>,
> we read under '2.9.1 Simple Commands'
>
> "Variable assignments shall be performed as follows:
> ...
> - If the command name is a standard utility implemented as a function
> (see XBD Utility), the effect of variable assignments shall be as if the
> utility was not implemented as a function.
> ...
> - If the command name is a function that is not a standard utility
> implemented as a function, variable assignments shall affect the current
> execution environment during the execution of the function. It is
> unspecified:
>
> * Whether or not the variable assignments persist after the
> completion of the function
>
> * Whether or not the variables gain the export attribute during
> the execution of the function
>
> * Whether or not export attributes gained as a result of the
> variable assignments persist after the completion of the function (if
> variable assignments persist after the completion of the function)"
POSIX used to require the current dash behaviour. However, you're
right that this is no longer the case.
This patch will remove the persistence of the variable assignment.
I have considered the exporting the variables during the function
execution but have decided against it because:
1) It makes the code bigger.
2) dash has never done this in the past.
3) You cannot use this portably anyway.
Reported-by: Dirk Fieldhouse <fieldhouse at gmx.net>
Signed-off-by: Herbert Xu <herbert at gondor.apana.org.au>
function old new delta
evalcommand 1606 1635 +29
evalcase 313 317 +4
evalfun 280 268 -12
pushlocalvars 48 - -48
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 2/1 up/down: 33/-60) Total: -27 bytes
Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
shell/ash.c | 3 ---
shell/ash_test/ash-misc/env_and_func.right | 2 +-
shell/ash_test/ash-misc/env_and_func.tests | 2 +-
shell/ash_test/ash-vars/var_leak.right | 2 +-
shell/ash_test/ash-vars/var_leak.tests | 4 +---
shell/hush_test/hush-misc/env_and_func.tests | 2 +-
6 files changed, 5 insertions(+), 10 deletions(-)
diff --git a/shell/ash.c b/shell/ash.c
index 5c431c9ff..6cda7251e 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -9600,9 +9600,7 @@ evalfun(struct funcnode *func, int argc, char **argv, int flags)
shellparam.optind = 1;
shellparam.optoff = -1;
#endif
- pushlocalvars();
evaltree(func->n.ndefun.body, flags & EV_TESTED);
- poplocalvars(0);
funcdone:
INT_OFF;
funcline = savefuncline;
@@ -10235,7 +10233,6 @@ evalcommand(union node *cmd, int flags)
goto readstatus;
case CMDFUNCTION:
- poplocalvars(1);
/* See above for the rationale */
dowait(DOWAIT_NONBLOCK, NULL);
if (evalfun(cmdentry.u.func, argc, argv, flags))
diff --git a/shell/ash_test/ash-misc/env_and_func.right b/shell/ash_test/ash-misc/env_and_func.right
index 5fc3488ae..4a1545058 100644
--- a/shell/ash_test/ash-misc/env_and_func.right
+++ b/shell/ash_test/ash-misc/env_and_func.right
@@ -1,2 +1,2 @@
var=val
-var=val
+var=old
diff --git a/shell/ash_test/ash-misc/env_and_func.tests b/shell/ash_test/ash-misc/env_and_func.tests
index 3efef1a41..1c63eafd8 100755
--- a/shell/ash_test/ash-misc/env_and_func.tests
+++ b/shell/ash_test/ash-misc/env_and_func.tests
@@ -3,6 +3,6 @@ f() { echo "var=$var"; }
# bash: POSIXLY_CORRECT behavior is to "leak" new variable values
# out of function invocations (similar to "special builtins" behavior);
# but in "bash mode", they don't leak.
-# hush does not "leak" values. ash does.
+# hush does not "leak" values. ash used to, but now does not.
var=val f
echo "var=$var"
diff --git a/shell/ash_test/ash-vars/var_leak.right b/shell/ash_test/ash-vars/var_leak.right
index 01a5e3263..764680086 100644
--- a/shell/ash_test/ash-vars/var_leak.right
+++ b/shell/ash_test/ash-vars/var_leak.right
@@ -1,4 +1,4 @@
should be empty: ''
should be empty: ''
should be not empty: 'val2'
-should be not empty: 'val3'
+should be empty: ''
diff --git a/shell/ash_test/ash-vars/var_leak.tests b/shell/ash_test/ash-vars/var_leak.tests
index 5242e24eb..adf66692e 100755
--- a/shell/ash_test/ash-vars/var_leak.tests
+++ b/shell/ash_test/ash-vars/var_leak.tests
@@ -15,9 +15,7 @@ VAR=''
VAR=val2 exec 2>&1
echo "should be not empty: '$VAR'"
-# ash follows the "function call is a special builtin" rule here
-# (bash does not do it)
f() { true; }
VAR=''
VAR=val3 f
-echo "should be not empty: '$VAR'"
+echo "should be empty: '$VAR'"
diff --git a/shell/hush_test/hush-misc/env_and_func.tests b/shell/hush_test/hush-misc/env_and_func.tests
index 3efef1a41..1c63eafd8 100755
--- a/shell/hush_test/hush-misc/env_and_func.tests
+++ b/shell/hush_test/hush-misc/env_and_func.tests
@@ -3,6 +3,6 @@ f() { echo "var=$var"; }
# bash: POSIXLY_CORRECT behavior is to "leak" new variable values
# out of function invocations (similar to "special builtins" behavior);
# but in "bash mode", they don't leak.
-# hush does not "leak" values. ash does.
+# hush does not "leak" values. ash used to, but now does not.
var=val f
echo "var=$var"
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