Add test for early backend startup errors

The new test tests the libpq fallback behavior on an early error,
which was fixed in the previous commit.

This adds an IS_INJECTION_POINT_ATTACHED() macro, to allow writing
injected test code alongside the normal source code. In principle, the
new test could've been implemented by an extra test module with a
callback that sets the FrontendProtocol global variable, but I think
it's more clear to have the test code right where the injection point
is, because it has pretty intimate knowledge of the surrounding
context it runs in.

Reviewed-by: Michael Paquier
Discussion: https://www.postgresql.org/message-id/CAOYmi%2Bnwvu21mJ4DYKUa98HdfM_KZJi7B1MhyXtnsyOO-PB6Ww%40mail.gmail.com

1 files changed, 14 insertions, 0 deletions

diff --git a/src/backend/utils/misc/injection_point.c b/src/backend/utils/misc/injection_point.c
index 8ab5bc63276..80bc32b0e08 100644
--- a/src/backend/utils/misc/injection_point.c
+++ b/src/backend/utils/misc/injection_point.c
@@ -570,3 +570,17 @@ InjectionPointCached(const char *name)
 	elog(ERROR, "Injection points are not supported by this build");
 #endif
 }
+
+/*
+ * Test if an injection point is defined.
+ */
+bool
+IsInjectionPointAttached(const char *name)
+{
+#ifdef USE_INJECTION_POINTS
+	return InjectionPointCacheRefresh(name) != NULL;
+#else
+	elog(ERROR, "Injection points are not supported by this build");
+	return false;				/* silence compiler */
+#endif
+}