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											     BASH PATCH REPORT

											     =================


								Bash-Release:	5.0

								Patch-ID:	bash50-010


								Bug-Reported-by:	Thorsten Glaser <tg@mirbsd.de>

								Bug-Reference-ID:	<156622962831.19438.16374961114836556294.reportbug@tglase.lan.tarent.de>

								Bug-Reference-URL:	https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=935115


								Bug-Description:


								Bash-5.0 changed the way assignment statements preceding special builtins

								and shell functions were handled in posix mode. They automatically created

								or modified global variables instead of modifying existing local variables

								as in bash-4.4.


								The bash-4.4 posix-mode semantics were buggy, and resulted in creating

								local variables where they were not intended and modifying global variables

								and local variables simultaneously.


								The bash-5.0 changes were intended to fix this issue, but did not preserve

								enough backwards compatibility. The posix standard also changed what it

								required in these cases, so bash-5.0 is not bound by the strict conformance

								requirements that existed in previous issues of the standard.


								This patch modifies the bash-5.0 posix mode behavior in an effort to restore

								some backwards compatibility and rationalize the behavior in the presence of

								local variables. It


								1. Changes the assignment semantics to be more similar to standalone assignment

								   statements: assignments preceding a function call or special builtin while

								   executing in a shell function will modify the value of a local variable

								   with the same name for the duration of the function's execution;


								2. Changes assignments preceding shell function calls or special builtins

								   from within a shell function to no longer create or modify global variables

								   in the presence of a local variable with the same name;


								3. Assignment statements preceding a shell function call or special builtin

								   at the global scope continue to modify the (global) calling environment,

								   but are unaffected by assignments preceding function calls or special

								   builtins within a function, as described in item 2. This is also similar

								   to the behavior of a standalone assignment statement.


								Patch (apply with `patch -p0'):


								*** a/variables.c	2018-12-18 11:07:21.000000000 -0500

								--- b/variables.c	2019-08-22 10:53:44.000000000 -0400

								***************

								*** 4461,4467 ****


								  /* Take a variable from an assignment statement preceding a posix special

								!    builtin (including `return') and create a global variable from it. This

								!    is called from merge_temporary_env, which is only called when in posix

								!    mode. */

								  static void

								  push_posix_temp_var (data)

								--- 4461,4467 ----


								  /* Take a variable from an assignment statement preceding a posix special

								!    builtin (including `return') and create a variable from it as if a

								!    standalone assignment statement had been performed. This is called from

								!    merge_temporary_env, which is only called when in posix mode. */

								  static void

								  push_posix_temp_var (data)

								***************

								*** 4473,4486 ****

								    var = (SHELL_VAR *)data;


								!   binding_table = global_variables->table;

								!   if (binding_table == 0)

								!     binding_table = global_variables->table = hash_create (VARIABLES_HASH_BUCKETS);

								!

								!   v = bind_variable_internal (var->name, value_cell (var), binding_table, 0, ASS_FORCE|ASS_NOLONGJMP);


								    /* global variables are no longer temporary and don't need propagating. */

								!   var->attributes &= ~(att_tempvar|att_propagate);

								    if (v)

								!     v->attributes |= var->attributes;


								    if (find_special_var (var->name) >= 0)

								--- 4473,4497 ----

								    var = (SHELL_VAR *)data;


								!   /* Just like do_assignment_internal(). This makes assignments preceding

								!      special builtins act like standalone assignment statements when in

								!      posix mode, satisfying the posix requirement that this affect the

								!      "current execution environment." */

								!   v = bind_variable (var->name, value_cell (var), ASS_FORCE|ASS_NOLONGJMP);

								!

								!   /* If this modifies an existing local variable, v->context will be non-zero.

								!      If it comes back with v->context == 0, we bound at the global context.

								!      Set binding_table appropriately. It doesn't matter whether it's correct

								!      if the variable is local, only that it's not global_variables->table */

								!   binding_table = v->context ? shell_variables->table : global_variables->table;


								    /* global variables are no longer temporary and don't need propagating. */

								!   if (binding_table == global_variables->table)

								!     var->attributes &= ~(att_tempvar|att_propagate);

								!

								    if (v)

								!     {

								!       v->attributes |= var->attributes;

								!       v->attributes &= ~att_tempvar;	/* not a temp var now */

								!     }


								    if (find_special_var (var->name) >= 0)

								***************

								*** 4576,4587 ****

								  {

								    int i;


								    tempvar_list = strvec_create (HASH_ENTRIES (temporary_env) + 1);

								    tempvar_list[tvlist_ind = 0] = 0;

								!

								!   hash_flush (temporary_env, pushf);

								!   hash_dispose (temporary_env);

								    temporary_env = (HASH_TABLE *)NULL;


								    tempvar_list[tvlist_ind] = 0;


								--- 4587,4601 ----

								  {

								    int i;

								+   HASH_TABLE *disposer;


								    tempvar_list = strvec_create (HASH_ENTRIES (temporary_env) + 1);

								    tempvar_list[tvlist_ind = 0] = 0;

								!

								!   disposer = temporary_env;

								    temporary_env = (HASH_TABLE *)NULL;


								+   hash_flush (disposer, pushf);

								+   hash_dispose (disposer);

								+

								    tempvar_list[tvlist_ind] = 0;


								*** a/tests/varenv.right	2018-12-17 15:39:48.000000000 -0500

								--- b/tests/varenv.right	2019-08-22 16:05:25.000000000 -0400

								***************

								*** 147,153 ****

								  outside: declare -- var="one"

								  inside: declare -x var="value"

								! outside: declare -x var="value"

								! inside: declare -- var="local"

								! outside: declare -x var="global"

								  foo=<unset> environment foo=

								  foo=foo environment foo=foo

								--- 147,153 ----

								  outside: declare -- var="one"

								  inside: declare -x var="value"

								! outside: declare -- var="outside"

								! inside: declare -x var="global"

								! outside: declare -- var="outside"

								  foo=<unset> environment foo=

								  foo=foo environment foo=foo

								*** a/patchlevel.h	2016-06-22 14:51:03.000000000 -0400

								--- b/patchlevel.h	2016-10-01 11:01:28.000000000 -0400

								***************

								*** 26,30 ****

								     looks for to find the patch level (for the sccs version string). */


								! #define PATCHLEVEL 9


								  #endif /* _PATCHLEVEL_H_ */

								--- 26,30 ----

								     looks for to find the patch level (for the sccs version string). */


								! #define PATCHLEVEL 10


								  #endif /* _PATCHLEVEL_H_ */