From f5b5d2c53ac9edd8d28e8caecf1bb44d04ad9d7d Mon Sep 17 00:00:00 2001
From: Oliver Tan <otan@cockroachlabs.com>
Date: Fri, 9 Dec 2022 18:15:29 -0500
Subject: [PATCH] clisqlshell: correctly handle sending zero input for COPY

Release note (bug fix): Previously, empty COPY commands would not escape
after an EOF character or error if encountering a `\.` with no input.
This is now resolved.
---
 pkg/cli/clisqlclient/copy.go            | 11 +++++++----
 pkg/cli/clisqlshell/sql.go              |  6 ++++--
 pkg/cli/interactive_tests/test_copy.tcl | 16 ++++++++++++++++
 3 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/pkg/cli/clisqlclient/copy.go b/pkg/cli/clisqlclient/copy.go
index 733aaaefeba6..7e2b57d72fee 100644
--- a/pkg/cli/clisqlclient/copy.go
+++ b/pkg/cli/clisqlclient/copy.go
@@ -96,10 +96,13 @@ func (c *CopyFromState) Commit(ctx context.Context, cleanupFunc func(), lines st
 	return func(ctx context.Context, conn Conn) (Rows, bool, error) {
 		defer cleanupFunc()
 		rows, isMulti, err := func() (Rows, bool, error) {
-			for _, l := range strings.Split(lines, "\n") {
-				_, err := c.copyFromer.CopyData(ctx, l)
-				if err != nil {
-					return nil, false, err
+			// Do not send anything if it is just an empty string.
+			if lines != "" {
+				for _, l := range strings.Split(lines, "\n") {
+					_, err := c.copyFromer.CopyData(ctx, l)
+					if err != nil {
+						return nil, false, err
+					}
 				}
 			}
 			r, err := c.copyFromer.Exec(nil)
diff --git a/pkg/cli/clisqlshell/sql.go b/pkg/cli/clisqlshell/sql.go
index a31814774380..756fb8666a85 100644
--- a/pkg/cli/clisqlshell/sql.go
+++ b/pkg/cli/clisqlshell/sql.go
@@ -974,6 +974,7 @@ func (c *cliState) doStartLine(nextState cliStateEnum) cliStateEnum {
 	c.atEOF = false
 	c.partialLines = c.partialLines[:0]
 	c.partialStmtsLen = 0
+	c.concatLines = ""
 
 	c.useContinuePrompt = false
 
@@ -1243,7 +1244,8 @@ func (c *cliState) doHandleCliCmd(loopState, nextState cliStateEnum) cliStateEnu
 
 	case `\.`:
 		if c.inCopy() {
-			c.concatLines += "\n" + `\.`
+			c.partialLines = append(c.partialLines, `\.`)
+			c.partialStmtsLen++
 			return cliRunStatement
 		}
 		return c.invalidSyntax(errState)
@@ -1602,7 +1604,7 @@ func (c *cliState) doPrepareStatementLine(
 		(c.inCopy() && (strings.HasSuffix(c.concatLines, "\n"+`\.`) || c.atEOF)) ||
 		// We're always at the end of a statement if EOF is reached in the
 		// single statement mode.
-		c.singleStatement && c.atEOF
+		(c.singleStatement && c.atEOF)
 	if c.atEOF {
 		// Definitely no more input expected.
 		if !endOfStmt {
diff --git a/pkg/cli/interactive_tests/test_copy.tcl b/pkg/cli/interactive_tests/test_copy.tcl
index de3362ba7d60..1a0713bd2aa4 100644
--- a/pkg/cli/interactive_tests/test_copy.tcl
+++ b/pkg/cli/interactive_tests/test_copy.tcl
@@ -28,6 +28,22 @@ eexpect "could not parse"
 
 end_test
 
+start_test "check EMPTY copy"
+
+send "COPY t FROM STDIN;\r"
+eexpect ">>"
+send_eof
+eexpect "COPY 0"
+eexpect root@
+
+send "COPY t FROM STDIN;\r"
+eexpect ">>"
+send "\\.\r"
+eexpect "COPY 0"
+eexpect root@
+
+end_test
+
 start_test "multi statement with COPY"
 send "SELECT 1; COPY t FROM STDIN CSV;\r"
 eexpect "COPY together with other statements in a query string is not supported"