5 files changed, 17 insertions, 0 deletions
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 7b030463013..bff949a40bc 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -9194,6 +9194,9 @@ reapply_stacked_values(struct config_generic *variable,
 	}
 }
 
+/*
+ * Functions for extensions to call to define their custom GUC variables.
+ */
 void
 DefineCustomBoolVariable(const char *name,
 						 const char *short_desc,
@@ -9333,6 +9336,10 @@ DefineCustomEnumVariable(const char *name,
 	define_custom_variable(&var->gen);
 }
 
+/*
+ * Extensions should call this after they've defined all of their custom
+ * GUCs, to help catch misspelled config-file entries,
+ */
 void
 EmitWarningsOnPlaceholders(const char *className)
 {
diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
index e11837559da..7c045f45607 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -474,6 +474,9 @@ _PG_init(void)
 							   PGC_SUSET, 0,
 							   NULL, NULL, NULL);
 
+	EmitWarningsOnPlaceholders("pltcl");
+	EmitWarningsOnPlaceholders("pltclu");
+
 	pltcl_pm_init_done = true;
 }
 
diff --git a/src/test/modules/delay_execution/delay_execution.c b/src/test/modules/delay_execution/delay_execution.c
index b3d0841ba80..8ec623ac527 100644
--- a/src/test/modules/delay_execution/delay_execution.c
+++ b/src/test/modules/delay_execution/delay_execution.c
@@ -91,6 +91,8 @@ _PG_init(void)
 							NULL,
 							NULL);
 
+	EmitWarningsOnPlaceholders("delay_execution");
+
 	/* Install our hook */
 	prev_planner_hook = planner_hook;
 	planner_hook = delay_execution_planner;
diff --git a/src/test/modules/ssl_passphrase_callback/ssl_passphrase_func.c b/src/test/modules/ssl_passphrase_callback/ssl_passphrase_func.c
index 6b0a3db104c..3ba33e501c3 100644
--- a/src/test/modules/ssl_passphrase_callback/ssl_passphrase_func.c
+++ b/src/test/modules/ssl_passphrase_callback/ssl_passphrase_func.c
@@ -48,6 +48,9 @@ _PG_init(void)
 							   NULL,
 							   NULL,
 							   NULL);
+
+	EmitWarningsOnPlaceholders("ssl_passphrase");
+
 	if (ssl_passphrase)
 		openssl_tls_init_hook = set_rot13;
 }
diff --git a/src/test/modules/worker_spi/worker_spi.c b/src/test/modules/worker_spi/worker_spi.c
index 0b6246676b6..adb02d8cb83 100644
--- a/src/test/modules/worker_spi/worker_spi.c
+++ b/src/test/modules/worker_spi/worker_spi.c
@@ -322,6 +322,8 @@ _PG_init(void)
 							   0,
 							   NULL, NULL, NULL);
 
+	EmitWarningsOnPlaceholders("worker_spi");
+
 	/* set up common data for all our workers */
 	memset(&worker, 0, sizeof(worker));
 	worker.bgw_flags = BGWORKER_SHMEM_ACCESS |