bash-5.0-003 and assignment-preceding-builtin.patch
OBS-URL: https://build.opensuse.org/package/show/Base:System/bash?expand=0&rev=288
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Dr. Werner Fink
Git OBS Bridge
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assignment-preceding-builtin.patch
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137
assignment-preceding-builtin.patch
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From: Chet Ramey
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Subject: Re: [bug-bash] bash-5.0: problem with variable scoping in posix-mode
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> > Description:
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> >
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> > There is a problem with variable scoping when variable is created from
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> > assignment statement preceding function call in posix-mode. See an
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> > example below.
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> >
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> >
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> > Repeat-By:
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> >
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> > $ cat test.sh
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> > #!/bin/sh
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> >
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> > myecho() {
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> > echo $var
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> > }
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> >
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> > foo() {
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> > local var="foo: FAIL"
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> > var="foo: bar" myecho
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> > }
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> >
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> > foo
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> >
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> > $ bash test.sh
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> > foo: bar
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> > $ bash --posix test.sh
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> > foo: FAIL
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>
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> This is a consequence of a combination of two POSIX features. First, POSIX
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> requires assignment statements preceding special builtins to create global
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> variables (POSIX has no local variables) that persist in the shell context
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> after the special builtin completes. Second, POSIX requires* that
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> assignment statements preceding function calls have the same variable-
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> assignment behavior as special builtins.
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>
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> So the variable assignment preceding the function call creates a global
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> variable, and the local variable is found before that global when `myecho'
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> is executed according to the standard bash dynamic scoping rules. If you
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> add an `echo $var' after the call to foo, you'll see this behavior.
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>
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> (*) The most recent version of the standard has removed this requirement
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> for shell functions, and I will change that behavior for the next release
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> of bash. Until then, the old behavior persists.
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This behavior is not quite backwards-compatible with bash-4.4. Here is a
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patch that implements a portion of the proposed bash-5.1 behavior. It
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changes the variable assignment semantics so that variable assignments
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preceding builtins and shell functions act more like standalone assignment
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statements and modify the "current execution environment" (in POSIX terms)
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instead of unconditionally modifying the global variable scope.
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This means that assignments preceding shell functions and special builtins
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will modify existing local variables and modifications to local variables
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will not propagate to the calling environment, and will create global
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variables if there is not an existing local variable with that name. This
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is compatible with other POSIX shells that implement local variables.
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It is not completely compatible with bash-4.4, since the bash-4.4 behavior
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wasn't fully POSIX-conformant and had variable scoping bugs as well.
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The original discussion concerning this is at
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http://lists.gnu.org/archive/html/bug-bash/2018-05/msg00002.html
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Chet
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---
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variables.c | 35 ++++++++++++++++++++++++++++++-----
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1 file changed, 30 insertions(+), 5 deletions(-)
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--- variables.c
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+++ variables.c 2019-03-21 08:21:21.777597991 +0000
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@@ -4507,16 +4507,38 @@ push_posix_temp_var (data)
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var = (SHELL_VAR *)data;
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+#if 1 /* TAG:bash-5.1 */
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+ /* Just like do_assignment_internal(). This makes assignments preceding
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+ special builtins act like standalone assignment statements when in
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+ posix mode, satisfying the posix requirement that this affect the
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+ "current execution environment." */
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+ v = bind_variable (var->name, value_cell (var), ASS_FORCE|ASS_NOLONGJMP);
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+
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+ /* If this modifies an existing local variable, v->context will be non-zero.
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+ If it comes back with v->context == 0, we bound at the global context.
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+ Set binding_table appropriately. It doesn't matter whether it's correct
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+ if the variable is local, only that it's not global_variables->table */
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+ binding_table = v->context ? shell_variables->table : global_variables->table;
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+#else
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binding_table = global_variables->table;
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if (binding_table == 0)
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binding_table = global_variables->table = hash_create (VARIABLES_HASH_BUCKETS);
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v = bind_variable_internal (var->name, value_cell (var), binding_table, 0, ASS_FORCE|ASS_NOLONGJMP);
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+#endif
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/* global variables are no longer temporary and don't need propagating. */
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- var->attributes &= ~(att_tempvar|att_propagate);
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+ if (binding_table == global_variables->table)
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+ var->attributes &= ~(att_tempvar|att_propagate);
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+
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if (v)
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- v->attributes |= var->attributes;
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+ {
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+ v->attributes |= var->attributes;
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+ v->attributes &= ~att_tempvar; /* not a temp var now */
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+#if 0 /* TAG:bash-5.1 code doesn't need this, disable for bash-5.1 */
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+ v->context = (binding_table == global_variables->table) ? 0 : shell_variables->scope;
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+#endif
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+ }
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if (find_special_var (var->name) >= 0)
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tempvar_list[tvlist_ind++] = savestring (var->name);
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@@ -4610,14 +4632,17 @@ dispose_temporary_env (pushf)
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sh_free_func_t *pushf;
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{
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int i;
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+ HASH_TABLE *disposer;
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tempvar_list = strvec_create (HASH_ENTRIES (temporary_env) + 1);
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tempvar_list[tvlist_ind = 0] = 0;
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-
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- hash_flush (temporary_env, pushf);
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- hash_dispose (temporary_env);
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+
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+ disposer = temporary_env;
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temporary_env = (HASH_TABLE *)NULL;
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+ hash_flush (disposer, pushf);
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+ hash_dispose (disposer);
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+
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tempvar_list[tvlist_ind] = 0;
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array_needs_making = 1;
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@ -1,3 +1,3 @@
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version https://git-lfs.github.com/spec/v1
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oid sha256:33cf9f650dd932d8a2fdf23073741d7e2b2816b6d396fa7190fcfefa5d034315
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size 4261
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oid sha256:eb4d73ccda613827fd57d051e1e747336ed8eecd1d8169d6e3aa9a458d18ce74
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size 4459
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12
bash.changes
12
bash.changes
@ -1,3 +1,15 @@
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-------------------------------------------------------------------
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Thu Mar 21 08:24:11 UTC 2019 - Dr. Werner Fink <werner@suse.de>
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- Add patch assignment-preceding-builtin.patch from upstream
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mailing list. Note that this break backward behaviour with
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bash-4.4 but implies that POSIX mode is more correct
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-------------------------------------------------------------------
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Thu Mar 21 07:57:41 UTC 2019 - Dr. Werner Fink <werner@suse.de>
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- Replace the temporary patch with official bash50-003
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-------------------------------------------------------------------
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Mon Mar 11 07:20:37 UTC 2019 - Dr. Werner Fink <werner@suse.de>
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@ -72,6 +72,8 @@ Patch47: bash-4.3-perl522.patch
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Patch48: bash-4.3-extra-import-func.patch
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# PATCH-EXTEND-SUSE Allow root to clean file system if filled up
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Patch49: bash-4.3-pathtemp.patch
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# PATCH-EXTEND-UPSTREAM bash-5.0: problem with variable scoping in posix-mode
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Patch100: assignment-preceding-builtin.patch
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BuildRequires: audit-devel
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BuildRequires: autoconf
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BuildRequires: bison
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@ -235,6 +237,7 @@ done
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%patch48 -b .eif
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%endif
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%patch49 -p0 -b .pthtmp
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%patch100 -p0 -b .posix
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%patch0 -p0 -b .0
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# This has to be always the same version as included in the bash its self
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