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Problem Report 0705 Details

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Report 0705 Actions

    Problem Report Number 0705
    Submitter's Classification Specification problem
    State Resolved
    Resolution Permanent Interpretation (PIN)
    Problem Resolution ID PIN.X.0098
    Raised 1970-01-01 08:00
    Updated 2003-03-13 08:00
    Published 1997-02-24 08:00
    Product Standard Commands and Utilities V2 (UNIX 95)
    Certification Program The Open Brand certification program
    Test Suite VSC version 4.1.5
    Test Identification POSIX.upe/ex 1013-1014
    Specification Commands and Utilities Issue 4 Version 2
    Location in Spec See Problem Text
    Problem Summary PIN4C.00016 This test may fail on implementations that implement historical ed compatible behavior.
    Problem Text

    Commands and Utilities, Issue 4, Version 2, p. 318, defines edcompatible as
    follows:

    edcompatible, ed
    [Default off]
    Causes the presence of g and c suffixes on substitute commands to be
    remembered, and toggled by repeating suffixes.

    Precise definitions of "remembered" and "toggled" are omitted, and no rules are
    supplied to govern their operation. VSC tests 1013 and 1014 test edcompatible
    and, perhaps not surprisingly given the loose definition, verify a different
    interpretation of the definitions than ours.

    We assert the historical behavior of the "remembered" function of edcompatible,
    which matches the behavior of our implementation, is summarized as follows:

    If edcompatible is set, and a substitute command is executed without a search
    pattern or options, then the search pattern and options specified in the pre-
    vious substitute command are used. In the case where no previous substitute
    command was issued, an error condition results.

    For example:

    Given a file with the contents:

    1 foo foo foo
    2 foo foo foo
    3 foo foo foo
    4 foo foo foo

    historically, the following behavior would be exhibited with edcompatible set:

    :set edcompatible
    :1s/foo/BAR/g # Replace all occurences of "foo" on line 1 with "BAR"
    BAR BAR BAR
    :2
    foo foo foo
    :s # Substitute, applying /foo/BAR/g from the previous cmd
    BAR BAR BAR # Replace all occurences of "foo" on line 2 with "BAR"
    :1,$
    BAR BAR BAR
    BAR BAR BAR
    foo foo foo
    foo foo foo
    :4s/foo/baz/ # Execute a new search command, with a new pattern and
    baz foo foo # a null option. The new remembered pattern and option
    # will be set to /foo/baz/

    We believe the historical behavior and our understanding of "toggled" is
    summarized by the following:

    If a single option on the substitute command is repeated, each additional
    specification of that option toggles it, turning it on or off. Option tog-
    gling applies only to a single command line; each command line is treated
    independently with respect to toggling.

    Historically, toggling occurs independently of the edcompatible setting.

    For example:

    For the line:

    1 foo foo foo

    a table of commands and their effect on that line follows:

    command result toggled state of global option
    --------------- ------------- ------------------------------
    :s/foo/BAR/g 1 BAR BAR BAR global scope on
    :s/foo/BAR/gg 1 BAR foo foo global scope off
    :s/foo/BAR/ggg 1 BAR BAR BAR global scope on
    :s/foo/BAR/gggg 1 BAR foo foo global scope off



    In VSC Test 1013, the original contents of the target file is:

    here is a file
    and another line

    The following commands are applied with edcompatible set:

    1,$s/e/X/g
    1,$s/i/Y/


    Given the historical behavior, one would expect the following result:

    Command 1:

    hXrX is a filX
    and anothXr linX

    Command 2:

    HXrX Ys a filX
    and anothXr lYnX

    Instead, the result expected by VSC is:

    hXrX Ys a fYlX
    and anothXr lYnX

    In other words, VSC expects the /g option to be remembered and applied during
    the execution of the second command, causing the 'i' in filX to be replaced
    with a 'Y'. This differs with the historical implementation of ex, which does
    carry over the g option when a search pattern is specified.

    In VSC Test 1014, the original contents of the target file is:

    here is a file
    and another line

    The substitute commands, also applied with edcompatible set, are:

    1,$s/e/X/g
    1,$s/a/Z/g

    Historically, this would produce:

    Command 1:

    hXrX is a filX
    and anothXr linX

    Command 2:

    hXrX is Z filX
    Znd ZnothXr linX

    Instead, the test expects:

    hXrX is Z filX
    Znd anothXr linX

    >From this behavior, one assumes the test expects the global option in the second
    command, which remembers the global option as having been set and remembered as
    a result of the first substitution command, to be toggled off. This would cause
    the second 'a' in the second line to not be replaced. In other words, it ex-
    pects option toggling to be applied over two commands, instead of being restric-
    ted to a single command.

    Given the specification is non-specific and the expected results diverge from
    historical practice, we feel the specification should be clarified, and the
    tests altered to verify the new definition. In the meantime, we feel a TSD
    should be issued to grandfather those implementations which conform to histori-
    cal practice.
    Test Output
    520|1 1 15471 1 1|Assertion #1013 (C): Test edcompatible set option with c/g
    520|1 1 15471 1 11|Standard output isn't the same as file 'ex_exp_1'
    520|1 1 15471 1 12|diff of "out.stdout" and "ex_exp_1":
    520|1 1 15471 1 13|*** out.stdout Fri Jan 10 14:42:22 1997
    520|1 1 15471 1 14|--- ex_exp_1 Fri Jan 10 14:41:49 1997
    520|1 1 15471 1 15|***************
    520|1 1 15471 1 16|*** 1,2 ****
    520|1 1 15471 1 17|! hXrX Ys a filX
    520|1 1 15471 1 18| and anothXr lYnX
    520|1 1 15471 1 19|--- 1,2 ----
    520|1 1 15471 1 20|! hXrX Ys a fYlX
    520|1 1 15471 1 21| and anothXr lYnX
    220|1 1 1 14:42:25|FAIL

    520|1 1 15739 1 1|Assertion #1014 (C): Test edcompatible set option without c/g
    520|1 1 15739 1 11|Standard output isn't the same as file 'ex_exp_1'
    520|1 1 15739 1 12|diff of "out.stdout" and "ex_exp_1":
    520|1 1 15739 1 13|*** out.stdout Fri Jan 10 14:43:23 1997
    520|1 1 15739 1 14|--- ex_exp_1 Fri Jan 10 14:42:51 1997
    520|1 1 15739 1 15|***************
    520|1 1 15739 1 16|*** 1,2 ****
    520|1 1 15739 1 17| hXrX is Z filX
    520|1 1 15739 1 18|! Znd ZnothXr linX
    520|1 1 15739 1 19|--- 1,2 ----
    520|1 1 15739 1 20| hXrX is Z filX
    520|1 1 15739 1 21|! Znd anothXr linX
    220|1 1 1 14:43:26|FAIL

    Review Information

    Review Type TSMA Review
    Start Date null
    Completed null
    Status Complete
    Review Recommendation No Resolution Given
    Review Response
    A permanent interpretation is recommended after review.

    The issue here is the definition of edcompatible:

    edcompatible, ed
    [Default off]
    Causes the presence of g and c suffixes on substitute commands to be
    remembered, and toggled by repeating suffixes.

    The test interprets "toggled by repeating suffixes" as a single
    occurance of the g suffix repeated on different substitution commands
    such as

    s/foo/bar/g
    s/me/you/g

    so that the g option becomes implicit on future substitution commands
    until the g suffix is specified again to toggle the behavior. For
    example,

    s/a/A/g explicit global substitution
    s/b/B/ implicit global subsitution
    s/c/C/g toggle g switch, no global substitution
    s/d/D/ no global substitution

    The submitter contrasts the current test to historial practice.
    While historical practice is not normative, we believe this claim
    is correct. Since it is possible to interpret the spec as
    mandating either behavior we think it likely that the historical
    behavior was intended and that the test is wrong.

    However, the spec is not clear and many implementations have
    branded after changing thier behavior to pass the current test.
    To fix the test then force these implementations to change
    once again seems unreasonable to us. Especially since we believe
    this issue to have little, if any noticable effect to anyone.

    Review Type Expert Group Review
    Start Date null
    Completed null
    Status Complete
    Review Resolution No Resolution Given
    Review Conclusion
    The specification is not clear on the definition of edcompatible.
    A Permanent Interpretation should be granted.

    Review Type SA Review
    Start Date null
    Completed null
    Status Complete
    Review Resolution Permanent Interpretation (PIN)
    Review Conclusion
    A Permanent Interpretation is granted.

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