feat: round out ODBC sqlcmd compatibility with missing features and fixes #623

dlevy-msft-sql · 2026-01-25T01:11:54Z

Summary

This PR adds several missing features and fixes to improve compatibility with the original ODBC-based sqlcmd, making go-sqlcmd a more complete drop-in replacement.

New Features

:HELP\ command - Display available sqlcmd commands
-p\ flag - Print performance statistics after each batch
-j\ flag - Print raw error messages without info/warning formatting
*:PERFTRACE file* - Redirect timing output to a file
*:SERVERLIST* - List available SQL Server instances on the network
*Multi-line \EXIT(query)* - Interactive mode now prompts for continuation when parentheses are unbalanced

Bug Fixes

Fixed -p\ statistics format to match ODBC sqlcmd output
Fixed potential panic on empty args slice in command parser

Breaking Change

⚠️ -u\ Unicode output no longer writes a BOM (Byte Order Mark)

Previously, go-sqlcmd wrote a UTF-16LE BOM (\FF FE) at the start of Unicode output files. This behavior differed from ODBC sqlcmd, which never wrote a BOM.

This change aligns go-sqlcmd with ODBC sqlcmd behavior. If you have scripts or processes that depend on the BOM being present in -u\ output files, you may need to adjust them.

ODBC sqlcmd Compatibility Improvements

Feature	Before	After	ODBC sqlcmd
-u\ output BOM	Wrote BOM	No BOM	No BOM ✓
-p\ statistics format	Different	Matches	Matches ✓
-r\ without argument	Required arg	Defaults to 0	Defaults to 0 ✓
\EXIT(query)\ multi-line	Not supported	Supported	Supported ✓
:HELP\ command	Missing	Available	Available ✓
:SERVERLIST\ command	Missing	Available	Available ✓

Testing

Added unit tests for all new features
Added integration tests for -p\ and -j\ flags
All existing tests pass

- Change from 'CPU time / elapsed time' to ODBC format: - Network packet size (bytes) - Transaction count (xacts) - Clock Time (total, avg, xacts per sec) - Move timing from runQuery() to goCommand()/exitCommand() for proper aggregate timing across 'GO n' executions - Add PrintPerformanceStatistics() method for ODBC-compatible output - Update README.md documentation - Add unit tests for statistics format

- Add pkg/sqlcmd/server_discovery.go with shared ListServers() function - Add :SERVERLIST interactive command (same functionality as -L flag) - Refactor -L flag to use shared ListServers() function - Remove duplicate listLocalServers() and parseInstances() from cmd/sqlcmd - Add :SERVERLIST to :HELP command output - Add test for :SERVERLIST command - Update README documentation

- Fix potential panic in helpCommand when args is empty non-nil slice - Fix potential panic in serverlistCommand when args is empty non-nil slice - Fix golangci-lint S1009 warning in perftraceCommand (redundant nil check)

- Add unit tests for parseInstanceData and FormatServerList in server_discovery_test.go - Add integration test for -j flag (raw errors output) in format_test.go - Add DefaultBrowserTimeout constant for server discovery - Add DefaultPacketSize constant for performance statistics - Improve PrintPerformanceStatistics documentation with output format details

- TestPrintStatisticsIntegration: executes real query and verifies stats output - TestRawErrorsIntegration: triggers real SQL error and verifies raw error format

- EXIT(query) now prompts for continuation when parentheses are unbalanced - Continuation prompt shows ' -> ' to indicate more input expected - Handles nested parentheses and quoted strings correctly - Works only in interactive mode (file-based scripts still require single line) - Adds isExitParenBalanced() helper to track paren/quote state - Adds readExitContinuation() to read additional lines until balanced - Updates README to remove the EXIT limitation from breaking changes

- Changed from UseBOM to IgnoreBOM for UTF-16LE output - ODBC sqlcmd does not write a BOM, so neither should go-sqlcmd - Updated test data files to expect no BOM - Removes this item from breaking changes documentation

Copilot

Pull request overview

This PR enhances go-sqlcmd to improve compatibility with the original ODBC-based sqlcmd by adding several missing features and fixing behavioral differences. The changes focus on making go-sqlcmd a more complete drop-in replacement for ODBC sqlcmd.

Changes:

Added new interactive commands (:HELP, :PERFTRACE, :SERVERLIST) for better usability
Implemented -p flag for performance statistics and -j flag for raw error output
Enhanced EXIT(query) to support multi-line input in interactive mode
Fixed Unicode output to match ODBC sqlcmd by removing BOM (breaking change)
Refactored server discovery code into a reusable package

Reviewed changes

Copilot reviewed 11 out of 13 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
pkg/sqlcmd/commands.go	Added `:HELP`, `:PERFTRACE`, `:SERVERLIST` commands; enhanced EXIT command for multi-line support; integrated performance statistics
pkg/sqlcmd/sqlcmd.go	Added `PrintStatistics` flag, `perftrace` writer, and `PrintPerformanceStatistics` method
pkg/sqlcmd/format.go	Added `rawErrors` flag to support `-j` flag for raw error output without formatting
pkg/sqlcmd/server_discovery.go	New file implementing server discovery functionality (refactored from cmd/sqlcmd/sqlcmd.go)
pkg/sqlcmd/server_discovery_test.go	New comprehensive tests for server discovery and formatting
pkg/sqlcmd/commands_test.go	Added tests for new commands (help, perftrace, serverlist) and multi-line EXIT functionality
pkg/sqlcmd/sqlcmd_test.go	Added integration tests for `-p` and `-j` flags
pkg/sqlcmd/format_test.go	Added tests for raw errors formatter option
cmd/sqlcmd/sqlcmd.go	Integrated new flags; removed duplicate server listing code in favor of refactored package
cmd/sqlcmd/testdata/unicodeout*.txt	Updated test expectations for BOM removal
README.md	Documented new features and removed obsolete BOM documentation
CHANGELOG.md	New file documenting all changes including breaking changes

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Copilot · 2026-01-25T03:26:04Z

pkg/sqlcmd/server_discovery.go

+					if len(instdict) == 0 {
+						break
+					}
+					results[strings.ToUpper(instdict["InstanceName"])] = instdict


Potential panic if the instance data doesn't contain "InstanceName" key. The code accesses instdict["InstanceName"] without checking if it exists first. While this may work in practice if SQL Server always returns this field, it's safer to check for existence to prevent panics.

Consider checking: if instanceName, ok := instdict["InstanceName"]; ok { results[strings.ToUpper(instanceName)] = instdict }

Copilot · 2026-01-25T03:26:04Z

pkg/sqlcmd/server_discovery.go

+		instdict := map[string]string{}
+		gotName := false
+		var name string
+		for _, token := range tokens {
+			if gotName {
+				instdict[name] = token
+				gotName = false
+			} else {
+				name = token
+				if len(name) == 0 {
+					if len(instdict) == 0 {
+						break
+					}
+					results[strings.ToUpper(instdict["InstanceName"])] = instdict
+					instdict = map[string]string{}


Variable naming inconsistency: instdict should be instDict to follow Go naming conventions (camelCase). This would be consistent with other variables in the function like gotName and outS.

Suggested change

instdict := map[string]string{}

gotName := false

var name string

for _, token := range tokens {

if gotName {

instdict[name] = token

gotName = false

} else {

name = token

if len(name) == 0 {

if len(instdict) == 0 {

break

}

results[strings.ToUpper(instdict["InstanceName"])] = instdict

instdict = map[string]string{}

instDict := map[string]string{}

gotName := false

var name string

for _, token := range tokens {

if gotName {

instDict[name] = token

gotName = false

} else {

name = token

if len(name) == 0 {

if len(instDict) == 0 {

break

}

results[strings.ToUpper(instDict["InstanceName"])] = instDict

instDict = map[string]string{}

dlevy-msft-sql · 2026-01-25T04:29:32Z

Closing in favor of smaller, focused PRs:

Implement -R flag for regional settings #628: -R regional settings
Implement :serverlist command #630: :serverlist command
Implement -p flag for print statistics #631: -p print statistics
Implement :perftrace command #632: :perftrace command

Remaining features from this PR will be split into separate PRs:

:help command
Multi-line EXIT(query)
-u BOM removal (breaking change)
-r default fix

dlevy-msft-sql added 12 commits January 24, 2026 16:28

Add :help command to display available sqlcmd commands

bf38142

Add -p flag for printing performance statistics after each batch

66d49c0

Add -j flag for printing raw error messages without formatting

0dcaa1b

Add :perftrace command to redirect timing output to file

f00e646

fix: prevent panic on empty args slice and fix linter warning

e7b839d

- Fix potential panic in helpCommand when args is empty non-nil slice - Fix potential panic in serverlistCommand when args is empty non-nil slice - Fix golangci-lint S1009 warning in perftraceCommand (redundant nil check)

test: add real integration tests for -p and -j flags

ae10879

- TestPrintStatisticsIntegration: executes real query and verifies stats output - TestRawErrorsIntegration: triggers real SQL error and verifies raw error format

fix: match ODBC sqlcmd -u behavior by not writing BOM

24475d5

- Changed from UseBOM to IgnoreBOM for UTF-16LE output - ODBC sqlcmd does not write a BOM, so neither should go-sqlcmd - Updated test data files to expect no BOM - Removes this item from breaking changes documentation

docs: add CHANGELOG.md with release notes for round-out features

05982b9

dlevy-msft-sql requested a review from Copilot January 25, 2026 03:21

Copilot started reviewing on behalf of dlevy-msft-sql January 25, 2026 03:21 View session

dlevy-msft-sql added this to the ODBC SQLCMD Interchangeability milestone Jan 25, 2026

Copilot AI reviewed Jan 25, 2026

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dlevy-msft-sql closed this Jan 25, 2026

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feat: round out ODBC sqlcmd compatibility with missing features and fixes #623

feat: round out ODBC sqlcmd compatibility with missing features and fixes #623

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feat: round out ODBC sqlcmd compatibility with missing features and fixes #623

feat: round out ODBC sqlcmd compatibility with missing features and fixes #623

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dlevy-msft-sql commented Jan 25, 2026

Summary

New Features

Bug Fixes

Breaking Change

ODBC sqlcmd Compatibility Improvements

Testing

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Pull request overview

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