feat: add -f codepage flag for input/output encoding

[dlevy-msft-sql]

Summary

Implements the -f flag from ODBC sqlcmd for specifying input and output file code pages.

Changes

• cmd/sqlcmd/sqlcmd.go: Added CodePage and ListCodePages fields, -f/--code-page flag, validation, and runtime application
• pkg/sqlcmd/codepage.go: Comprehensive codepage support with parsing and encoding conversion
• pkg/sqlcmd/codepage_test.go: Unit tests for codepage parsing and supported encodings
• pkg/sqlcmd/commands.go: Updated :R command to respect codepage settings when reading files
• pkg/sqlcmd/sqlcmd.go: Added CodePage field to Sqlcmd struct
• cmd/sqlcmd/sqlcmd_test.go: Command line argument tests for valid and invalid codepage values
• README.md: Documentation with format examples

Usage

# Single codepage for both input and output
sqlcmd -S server -f 65001 -i script.sql -o results.txt

# Different codepages for input and output
sqlcmd -S server -f i:1252,o:65001 -i windows_script.sql -o utf8_results.txt

# List all supported codepages
sqlcmd --list-codepages

Supported Codepages

• Unicode: 65001 (UTF-8), 1200 (UTF-16LE), 1201 (UTF-16BE)
• Windows: 874, 1250-1258
• OEM/DOS: 437, 850, etc.
• ISO-8859: 28591-28606
• CJK: 932 (Shift-JIS), 936 (GB2312), 949 (Korean), 950 (Big5)
• EBCDIC: 37, 1047, 1140

Testing

• All existing tests pass
• Added command line argument parsing tests
• Added unit tests for codepage parsing and validation

Improves ODBC sqlcmd compatibility.

[dlevy-msft-sql]

Supersedes #627

[Copilot]

Pull request overview

This PR adds configurable input/output code page handling to the legacy sqlcmd CLI, improving compatibility with ODBC sqlcmd and enabling legacy-encoding workflows.

Changes:

• Introduces a central code page registry and parsing logic (-f / --code-page) with support for many Windows, OEM, ISO-8859, CJK, and EBCDIC encodings and a --list-codepages listing mode.
• Wires code page settings through the legacy CLI into the core Sqlcmd engine so :R, :OUT, and :ERROR commands correctly decode input files and encode output/error files according to the configured code pages.
• Adds comprehensive unit tests for code page parsing/lookup and CLI argument validation, plus README documentation and examples for the new functionality.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
pkg/sqlcmd/sqlcmd_test.go	Adds tests to verify IncludeFile decodes input files correctly under various input code pages (Windows-1252, UTF-16LE/BE with and without BOM).
pkg/sqlcmd/sqlcmd.go	Extends Sqlcmd with a CodePage field and updates IncludeFile to select an appropriate io.Reader based on configured input code page or BOM auto-detection.
pkg/sqlcmd/commands_test.go	Adds tests confirming :OUT and :ERROR commands honor the configured output code page when writing to files.
pkg/sqlcmd/commands.go	Introduces a transformWriteCloser helper and updates :OUT/:ERROR commands to encode output using the selected code page while ensuring underlying files are closed correctly.
pkg/sqlcmd/codepage_windows.go	Implements Windows-specific encoding.Encoding support backed by MultiByteToWideChar/WideCharToMultiByte for system-installed code pages not in the built-in registry.
pkg/sqlcmd/codepage_test.go	Adds tests for ParseCodePage, GetEncoding, SupportedCodePages, and Windows-specific fallback behavior, including round-trip checks for a Windows-only EBCDIC code page.
pkg/sqlcmd/codepage_other.go	Provides a non-Windows implementation of getSystemCodePageEncoding that surfaces a clear error for unsupported system code pages.
pkg/sqlcmd/codepage.go	Defines the cross-platform code page registry, CodePageSettings, parsing/validation logic for -f, and a SupportedCodePages API used by the CLI.
cmd/sqlcmd/sqlcmd_test.go	Extends CLI argument tests to cover -f / --code-page, --list-codepages, and various invalid code page argument combinations.
cmd/sqlcmd/sqlcmd.go	Adds CodePage and ListCodePages arguments, validates and stores parsed CodePageSettings, applies them to the Sqlcmd instance, and implements --list-codepages output formatting.
README.md	Documents the new -f flag, describes supported code pages, provides usage examples, and explains --list-codepages and default BOM auto-detection behavior.

[Copilot]

Pull request overview

Copilot reviewed 11 out of 11 changed files in this pull request and generated 4 comments.

[Copilot]

Pull request overview

Copilot reviewed 11 out of 11 changed files in this pull request and generated no new comments.

[shueybubbles]

lizer.Errorf

there's no localizable content in the format string so don't need to use localizer

[shueybubbles]

", "Code", "Name", "Description")

does this string need to be localizable?

[shueybubbles]

%s'%s': Unknown command. Enter '--help' for command help

does this string need to be localizable?

[shueybubbles]

  		err = localizer.Errorf("The -L parameter can not be used in combination with other parameters.")

should list code pages get the same exclusivity treatment as list servers?

---

Refers to: cmd/sqlcmd/sqlcmd.go:150 in a672f7f. [](commit_id = a672f7f, deletion_comment = False)

[shueybubbles]