Bug 1309296 - Bash3 to bash4 behavior change on here doc inside comsub - $( ... )
Summary: Bash3 to bash4 behavior change on here doc inside comsub - $( ... )
Keywords:
Status: CLOSED WONTFIX
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: bash
Version: 6.7
Hardware: All
OS: All
medium
medium
Target Milestone: rc
: ---
Assignee: Siteshwar Vashisht
QA Contact: BaseOS QE - Apps
URL:
Whiteboard:
Depends On:
Blocks: 1269194 1460933
TreeView+ depends on / blocked
 
Reported: 2016-02-17 12:10 UTC by Paulo Andrade
Modified: 2019-10-10 11:14 UTC (History)
0 users

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
: 1460933 (view as bug list)
Environment:
Last Closed: 2017-06-13 07:49:45 UTC
Target Upstream Version:


Attachments (Terms of Use)
comsub-eof.sh (99 bytes, text/plain)
2016-02-17 12:10 UTC, Paulo Andrade
no flags Details
bash-4.2-heredoc-paren-delim.patch (1.78 KB, patch)
2016-02-17 12:13 UTC, Paulo Andrade
no flags Details | Diff

Description Paulo Andrade 2016-02-17 12:10:38 UTC
Created attachment 1127918 [details]
comsub-eof.sh

In rhel5, the test case would work and not produce any
warnings. In rhel6 or newer it fails.

  Some users have scripts that rely on this behavior, that
did work on previous versions of bash, and works with old
and current versions of ksh.

  This is an inconsistency of $() versus ``, as with back
tildes it works with current bash version.

  The attached test case is bash/tests/comsub-eof4.sub and
bash/tests/comsub-eof5.sub that explicitly test for the
failure. *But* in bash/parse.y there is also a comment
about supporting this feature:

"""
      /* XXX -- possibly allow here doc to be delimited by ending right
	 paren. */
      if ((tflags & LEX_INHEREDOC) && ch == close && count == 1)
	{
	  int tind;
/*itrace("parse_comsub: in here doc, ch == close, retind - firstind = %d hdlen = %d retind = %d", retind-lex_firstind, hdlen, retind);*/
	  tind = lex_firstind;
	  while ((tflags & LEX_STRIPDOC) && ret[tind] == '\t')
"""

Comment 1 Paulo Andrade 2016-02-17 12:13:37 UTC
Created attachment 1127922 [details]
bash-4.2-heredoc-paren-delim.patch

This patch, built and tested on rhel7 corrects the issue.

Note that while the patch should be fully functional, and
tests quite a lot of the parser state, it should be possible
to write a simpler one, but I preferred to make a chain of
tests to avoid it being triggered on non matching conditions.


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