psql: Fix some scan-build warnings

A repeated complaint was that scan-build thought that if the \timing
setting changes during processing of a query, the post-processing
might read garbage time values.  This is probably not possible right
now, but it's not entirely inconceivable given the code structure.  So
silence this warning with small restructuring that makes this more
robust.  The other warnings were a few dead stores that are easy to
remove.

Discussion: https://www.postgresql.org/message-id/2570e2ae-fa0f-aac9-f72f-bb59a9983a20@enterprisedb.com

src/bin/psql/common.c

@@ -594,6 +594,7 @@ PSQLexec(const char *query)
 int
 PSQLexecWatch(const char *query, const printQueryOpt *opt, FILE *printQueryFout)
 {
+	bool		timing = pset.timing;
 	PGresult   *res;
 	double		elapsed_msec = 0;
 	instr_time	before;
@@ -608,7 +609,7 @@ PSQLexecWatch(const char *query, const printQueryOpt *opt, FILE *printQueryFout)
 
 	SetCancelConn(pset.db);
 
-	if (pset.timing)
+	if (timing)
 		INSTR_TIME_SET_CURRENT(before);
 
 	res = PQexec(pset.db, query);
@@ -621,7 +622,7 @@ PSQLexecWatch(const char *query, const printQueryOpt *opt, FILE *printQueryFout)
 		return 0;
 	}
 
-	if (pset.timing)
+	if (timing)
 	{
 		INSTR_TIME_SET_CURRENT(after);
 		INSTR_TIME_SUBTRACT(after, before);
@@ -674,7 +675,7 @@ PSQLexecWatch(const char *query, const printQueryOpt *opt, FILE *printQueryFout)
 	fflush(fout);
 
 	/* Possible microtiming output */
-	if (pset.timing)
+	if (timing)
 		PrintTiming(elapsed_msec);
 
 	return 1;
@@ -1192,6 +1193,7 @@ PrintQueryResults(PGresult *results)
 bool
 SendQuery(const char *query)
 {
+	bool		timing = pset.timing;
 	PGresult   *results;
 	PGTransactionStatusType transaction_status;
 	double		elapsed_msec = 0;
@@ -1300,7 +1302,7 @@ SendQuery(const char *query)
 		instr_time	before,
 					after;
 
-		if (pset.timing)
+		if (timing)
 			INSTR_TIME_SET_CURRENT(before);
 
 		results = PQexec(pset.db, query);
@@ -1309,7 +1311,7 @@ SendQuery(const char *query)
 		ResetCancelConn();
 		OK = ProcessResult(&results);
 
-		if (pset.timing)
+		if (timing)
 		{
 			INSTR_TIME_SET_CURRENT(after);
 			INSTR_TIME_SUBTRACT(after, before);
@@ -1400,7 +1402,7 @@ SendQuery(const char *query)
 	ClearOrSaveResult(results);
 
 	/* Possible microtiming output */
-	if (pset.timing)
+	if (timing)
 		PrintTiming(elapsed_msec);
 
 	/* check for events that may occur during query execution */
@@ -1471,6 +1473,7 @@ sendquery_cleanup:
 static bool
 DescribeQuery(const char *query, double *elapsed_msec)
 {
+	bool		timing = pset.timing;
 	PGresult   *results;
 	bool		OK;
 	instr_time	before,
@@ -1478,7 +1481,7 @@ DescribeQuery(const char *query, double *elapsed_msec)
 
 	*elapsed_msec = 0;
 
-	if (pset.timing)
+	if (timing)
 		INSTR_TIME_SET_CURRENT(before);
 
 	/*
@@ -1550,7 +1553,7 @@ DescribeQuery(const char *query, double *elapsed_msec)
 			results = PQexec(pset.db, buf.data);
 			OK = AcceptResult(results);
 
-			if (pset.timing)
+			if (timing)
 			{
 				INSTR_TIME_SET_CURRENT(after);
 				INSTR_TIME_SUBTRACT(after, before);
@@ -1591,6 +1594,7 @@ ExecQueryUsingCursor(const char *query, double *elapsed_msec)
 	PGresult   *results;
 	PQExpBufferData buf;
 	printQueryOpt my_popt = pset.popt;
+	bool		timing = pset.timing;
 	FILE	   *fout;
 	bool		is_pipe;
 	bool		is_pager = false;
@@ -1610,7 +1614,7 @@ ExecQueryUsingCursor(const char *query, double *elapsed_msec)
 	my_popt.topt.stop_table = false;
 	my_popt.topt.prior_records = 0;
 
-	if (pset.timing)
+	if (timing)
 		INSTR_TIME_SET_CURRENT(before);
 
 	/* if we're not in a transaction, start one */
@@ -1640,7 +1644,7 @@ ExecQueryUsingCursor(const char *query, double *elapsed_msec)
 	if (!OK)
 		goto cleanup;
 
-	if (pset.timing)
+	if (timing)
 	{
 		INSTR_TIME_SET_CURRENT(after);
 		INSTR_TIME_SUBTRACT(after, before);
@@ -1682,13 +1686,13 @@ ExecQueryUsingCursor(const char *query, double *elapsed_msec)
 
 	for (;;)
 	{
-		if (pset.timing)
+		if (timing)
 			INSTR_TIME_SET_CURRENT(before);
 
 		/* get fetch_count tuples at a time */
 		results = PQexec(pset.db, fetch_cmd);
 
-		if (pset.timing)
+		if (timing)
 		{
 			INSTR_TIME_SET_CURRENT(after);
 			INSTR_TIME_SUBTRACT(after, before);
@@ -1802,7 +1806,7 @@ ExecQueryUsingCursor(const char *query, double *elapsed_msec)
 	}
 
 cleanup:
-	if (pset.timing)
+	if (timing)
 		INSTR_TIME_SET_CURRENT(before);
 
 	/*
@@ -1828,7 +1832,7 @@ cleanup:
 		ClearOrSaveResult(results);
 	}
 
-	if (pset.timing)
+	if (timing)
 	{
 		INSTR_TIME_SET_CURRENT(after);
 		INSTR_TIME_SUBTRACT(after, before);

src/bin/psql/copy.c

@@ -660,7 +660,6 @@ handleCopyIn(PGconn *conn, FILE *copystream, bool isbinary, PGresult **res)
 				if (PQputCopyData(conn, buf, buflen) <= 0)
 				{
 					OK = false;
-					copydone = true;
 					break;
 				}
 

src/bin/psql/describe.c

@@ -635,7 +635,6 @@ describeFunctions(const char *functypes, const char *func_pattern,
 				appendPQExpBufferStr(&buf, "p.prokind = 'w'\n");
 			else
 				appendPQExpBufferStr(&buf, "p.proiswindow\n");
-			needs_or = true;
 		}
 		appendPQExpBufferStr(&buf, "      )\n");
 	}