Fix -h and -help flags to show help instead of requiring arguments

[Copilot]

Fix -h and -help flags to show help instead of requiring arguments

sqlcmd -h returns "Missing argument" error because -h expects an integer for header count. Additionally, -? requires quoting in zsh due to glob expansion, making help discovery difficult.

Changes

Argument preprocessing in cmd/sqlcmd/sqlcmd.go:

• Added preprocessHelpFlags() that converts -h to -? when not followed by a number
• Converts -help to --help (avoids shell parsing issues)
• Preserves -h <number> for backward compatibility with header count flag
• NEW: Consumes non-numeric, non-flag arguments after -h to prevent "Unknown command" errors

// Before: sqlcmd -h → "Missing argument" error
//         sqlcmd -h abc → "Unknown command: abc" error
// After:  sqlcmd -h → shows help
//         sqlcmd -h abc → shows help (consumes 'abc')
//         sqlcmd -h -E → shows help (preserves '-E' flag)
//         sqlcmd -h 10 → sets header count (unchanged)
//         sqlcmd -help → shows help

Test coverage in cmd/sqlcmd/sqlcmd_test.go:

• Conversion logic tests (7 cases)
• End-to-end parsing tests (3 cases)
• Validates both help behavior and backward compatibility

Verification

✅ All tests pass
✅ sqlcmd -h abc now shows help (instead of "Unknown command" error)
✅ sqlcmd -h -E shows help and preserves -E flag
✅ Backward compatibility maintained: sqlcmd -h 10 still sets header count

Original prompt

---

This section details on the original issue you should resolve

<issue_title>sqlcmd -? and sqlcmd -h are not working as expected</issue_title>
<issue_description>I am on macOS, zsh shell.

~ % sqlcmd -h
Sqlcmd: '-h': Missing argument. Enter '-?' for help.

~ % sqlcmd -?
zsh: no matches found: -?

sqlcmd --help gives the expected output.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes sqlcmd -? and sqlcmd -h are not working as expected #604

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[Copilot]

Pull request overview

This PR fixes the behavior of the -h and -help flags to show help instead of requiring arguments, addressing issue #604 where sqlcmd -h returned a "Missing argument" error and sqlcmd -? requires quoting in zsh due to glob expansion.

Changes:

• Added preprocessHelpFlags() function that converts -h to -? when not followed by a number, preserving backward compatibility with -h <number> for setting header count
• Converts -help to --help to avoid shell parsing issues (since -help would be parsed as -h elp)
• Added comprehensive test coverage for the new conversion logic and end-to-end parsing behavior

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
cmd/sqlcmd/sqlcmd.go	Implements preprocessHelpFlags() function with logic to detect numeric vs non-numeric arguments following -h, and integrates it into the argument preprocessing pipeline
cmd/sqlcmd/sqlcmd_test.go	Adds 10 new test cases covering conversion logic (7 tests in TestConvertOsArgs) and end-to-end parsing behavior (3 tests in TestValidCommandLineToArgsConversion)

[dlevy-msft-sql]

@copilot fix the review items

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.

[dlevy-msft-sql]

Replaced by cleaner implementation in #707