[PATCH v2] sparse-checkout: be consistent with end of options markers

From: Elijah Newren <newren@gmail.com>

93851746 (parse-options: decouple "--end-of-options" and "--", 2023-12-06) updated the world order to make callers of parse-options that set PARSE_OPT_KEEP_UNKNOWN_OPT responsible for deciding what to do with "--end-of-options" they may see after parse_options() returns.

This made a previous bug in sparse-checkout more visible; namely, that

  git sparse-checkout [add|set] --[no-]cone --end-of-options ...

would simply treat "--end-of-options" as one of the paths to include in the sparse-checkout. But this was already problematic before; namely,

  git sparse-checkout [add|set| --[no-]cone --sikp-checks ...

would not give an error on the mis-typed "--skip-checks" but instead simply treat "--sikp-checks" as a path or pattern to include in the sparse-checkout, which is highly unfriendly.

This behavior began when the command was converted to parse-options in 7bffca95ea (sparse-checkout: add '--stdin' option to set subcommand, 2019-11-21). Back then it was just called KEEP_UNKNOWN. Later it was renamed to KEEP_UNKNOWN_OPT in 99d86d60e5 (parse-options: PARSE_OPT_KEEP_UNKNOWN only applies to --options, 2022-08-19) to clarify that it was only about dashed options; we always keep non-option arguments. Looking at that original patch, both Peff and I think that the author was simply confused about the mis-named option, and really just wanted to keep the non-option arguments. We never should have used the flag all along (and the other cases were cargo-culted within the file).

Remove the erroneous PARSE_OPT_KEEP_UNKNOWN_OPT flag now to fix this bug. Note that this does mean that anyone who might have been using

  git sparse-checkout [add|set] [--[no-]cone] --foo --bar

to request paths or patterns '--foo' and '--bar' will now have to use

  git sparse-checkout [add|set] [--[no-]cone] -- --foo --bar

That makes sparse-checkout more consistent with other git commands, provides users much friendlier error messages and behavior, and is consistent with the all-caps warning in git-sparse-checkout.txt that this command "is experimental...its behavior...will likely change". :-)

Signed-off-by: Elijah Newren <newren@gmail.com>
---
    [RFC] sparse-checkout: be consistent with end of options markers
    
    Follow-up to thread over at
    https://lore.kernel.org/git/CABPp-BF9XZeESHdxdcZ91Vsn5tKqQ6_3tC11e7t9vTFp=uufbg@mail.gmail.com/,
    making end of options markers in git-sparse-checkout consistent with how
    other git commands behave.
    
    Changes since v1:
    
     * Added some testcases

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1625%2Fgitgitgadget%2Fsparse-checkout-end-of-options-consistency-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1625/gitgitgadget/sparse-checkout-end-of-options-consistency-v2
Pull-Request: https://github.com/git/git/pull/1625

Range-diff vs v1:

 1:  c19156919a6 ! 1:  448146637a9 sparse-checkout: be consistent with end of options markers
     @@ Commit message
          simply treat "--sikp-checks" as a path or pattern to include in the
          sparse-checkout, which is highly unfriendly.
      
     -    This behavior begain when the command was converted to parse-options in
     +    This behavior began when the command was converted to parse-options in
          7bffca95ea (sparse-checkout: add '--stdin' option to set subcommand,
          2019-11-21).  Back then it was just called KEEP_UNKNOWN. Later it was
          renamed to KEEP_UNKNOWN_OPT in 99d86d60e5 (parse-options:
     @@ Commit message
      
          That makes sparse-checkout more consistent with other git commands,
          provides users much friendlier error messages and behavior, and is
     -    consistent with the all-capps warning in git-sparse-checkout.txt that
     +    consistent with the all-caps warning in git-sparse-checkout.txt that
          this command "is experimental...its behavior...will likely change".  :-)
      
          Signed-off-by: Elijah Newren <newren@gmail.com>
     @@ builtin/sparse-checkout.c: static int sparse_checkout_check_rules(int argc, cons
       
       	if (check_rules_opts.rules_file && check_rules_opts.cone_mode < 0)
       		check_rules_opts.cone_mode = 1;
     +
     + ## t/t1091-sparse-checkout-builtin.sh ##
     +@@ t/t1091-sparse-checkout-builtin.sh: test_expect_success 'cone mode: set with nested folders' '
     + 
     + test_expect_success 'cone mode: add independent path' '
     + 	git -C repo sparse-checkout set deep/deeper1 &&
     +-	git -C repo sparse-checkout add folder1 &&
     ++	git -C repo sparse-checkout add --end-of-options folder1 &&
     + 	cat >expect <<-\EOF &&
     + 	/*
     + 	!/*/
     +@@ t/t1091-sparse-checkout-builtin.sh: test_expect_success 'by default, cone mode will error out when passed files' '
     + 	grep ".gitignore.*is not a directory" error
     + '
     + 
     ++test_expect_success 'error on mistyped command line options' '
     ++	test_must_fail git -C repo sparse-checkout add --sikp-checks .gitignore 2>error &&
     ++
     ++	grep "unknown option.*sikp-checks" error
     ++'
     ++
     + test_expect_success 'by default, non-cone mode will warn on individual files' '
     + 	git -C repo sparse-checkout reapply --no-cone &&
     + 	git -C repo sparse-checkout add .gitignore 2>warning &&

 builtin/sparse-checkout.c          | 9 +++------
 t/t1091-sparse-checkout-builtin.sh | 8 +++++++-
 2 files changed, 10 insertions(+), 7 deletions(-)