Merge pull request cockroachdb#19364 from knz/20171019-help-user

cli/sql: help users who enter a single '?' further
petermattis · Oct 20, 2017 · b18e300 · b18e300
2 parents ac51df3 + b8e8dfa
commit b18e300
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Showing 3 changed files with 28 additions and 6 deletions.
diff --git a/pkg/cli/interactive_tests/test_contextual_help.tcl b/pkg/cli/interactive_tests/test_contextual_help.tcl
@@ -62,6 +62,18 @@ eexpect "See also"
 eexpect root@
 end_test
 
+start_test "Check that a useful reminder is given if the user mistakenly uses a single ?."
+send "select ?\r"
+eexpect "Note:"
+eexpect JSON
+eexpect "use '??'"
+eexpect " ->"
+# restore the normal state
+send ";\r"
+eexpect HINT
+eexpect root@
+end_test
+
 
 start_test "Check that ??-tab works."
 send "select ??\t"

diff --git a/pkg/cli/sql.go b/pkg/cli/sql.go
@@ -327,15 +327,19 @@ func (c *cliState) handleUnset(args []string, nextState, errState cliStateEnum)
 	return nextState
 }
 
-func isEndOfStatement(fullStmt string) (isEmpty, isEnd bool) {
+func checkTokens(fullStmt string) (isEmpty bool, lastTok int) {
 	sc := parser.MakeScanner(fullStmt)
 	isEmpty = true
 	var last int
 	sc.Tokens(func(t int) {
 		isEmpty = false
 		last = t
 	})
-	return isEmpty, last == ';' || last == parser.HELPTOKEN
+	return isEmpty, last
+}
+
+func isEndOfStatement(lastTok int) bool {
+	return lastTok == ';' || lastTok == parser.HELPTOKEN
 }
 
 // handleHelp prints SQL help.
@@ -849,7 +853,8 @@ func (c *cliState) doPrepareStatementLine(
 		return startState
 	}
 
-	isEmpty, endsWithSemi := isEndOfStatement(c.concatLines)
+	isEmpty, lastTok := checkTokens(c.concatLines)
+	endOfStmt := isEndOfStatement(lastTok)
 	if c.partialStmtsLen == 0 && isEmpty {
 		// More whitespace, or comments. Still nothing to do. However
 		// if the syntax was non-trivial to arrive here,
@@ -861,14 +866,18 @@ func (c *cliState) doPrepareStatementLine(
 	}
 	if c.atEOF {
 		// Definitely no more input expected.
-		if !endsWithSemi {
+		if !endOfStmt {
 			fmt.Fprintf(stderr, "missing semicolon at end of statement: %s\n", c.concatLines)
 			c.exitErr = fmt.Errorf("last statement was not executed: %s", c.concatLines)
 			return cliStop
 		}
 	}
 
-	if !endsWithSemi {
+	if !endOfStmt {
+		if lastTok == '?' {
+			fmt.Fprintf(c.ins.Stdout(),
+				"Note: a single '?' is a JSON operator. If you want contextual help, use '??'.\n")
+		}
 		return contState
 	}
 

diff --git a/pkg/cli/sql_test.go b/pkg/cli/sql_test.go
@@ -190,10 +190,11 @@ func TestIsEndOfStatement(t *testing.T) {
 	}
 
 	for _, test := range tests {
-		isEmpty, isEnd := isEndOfStatement(test.in)
+		isEmpty, lastTok := checkTokens(test.in)
 		if isEmpty != test.isEmpty {
 			t.Errorf("%q: isEmpty expected %v, got %v", test.in, test.isEmpty, isEmpty)
 		}
+		isEnd := isEndOfStatement(lastTok)
 		if isEnd != test.isEnd {
 			t.Errorf("%q: isEnd expected %v, got %v", test.in, test.isEnd, isEnd)
 		}