Merge branch 'v2.1.x' into develop

.github/workflows/buildimage.yml

@@ -16,7 +16,7 @@ env:
 jobs:
   build-osx:
     name: Build for Darwin x86_64
-    runs-on: macos-13
+    runs-on: macos-15-intel
     steps:
       - name: Install PostgreSQL@14
         run: brew install --force postgresql@14

CHANGELOG.md

@@ -1,3 +1,7 @@
+## v2.1.5 [2026-02-06]
+_Bug fixes_
+- Fix memory leaks caused by unfreed `C.CString()` allocations across multiple functions. ([#618](https://github.com/turbot/steampipe-postgres-fdw/pull/618), [#620](https://github.com/turbot/steampipe-postgres-fdw/pull/620), [#622](https://github.com/turbot/steampipe-postgres-fdw/pull/622), [#624](https://github.com/turbot/steampipe-postgres-fdw/pull/624), [#631](https://github.com/turbot/steampipe-postgres-fdw/pull/631))
+
 ## v2.1.4 [2025-11-20]
 _Dependencies_
 - Upgraded dependencies to remediate vulnerabilities.

explain.go

@@ -6,6 +6,7 @@ package main
 #include "fdw_helpers.h"
 */
 import "C"
+import "unsafe"
 
 // Explainable is an optional interface for Iterator that can explain it's execution plan.
 type Explainable interface {
@@ -20,5 +21,9 @@ type Explainer struct {
 
 // Property adds a key-value property to results of EXPLAIN query.
 func (e Explainer) Property(k, v string) {
-	C.ExplainPropertyText(C.CString(k), C.CString(v), e.ES)
+	ck := C.CString(k)
+	cv := C.CString(v)
+	defer C.free(unsafe.Pointer(ck))
+	defer C.free(unsafe.Pointer(cv))
+	C.ExplainPropertyText(ck, cv, e.ES)
 }

fdw.go

@@ -268,9 +268,11 @@ func goFdwExplainForeignScan(node *C.ForeignScanState, es *C.ExplainState) {
 
 //export goFdwBeginForeignScan
 func goFdwBeginForeignScan(node *C.ForeignScanState, eflags C.int) {
+	// Outer recover: catches panics during early initialization (before inner defer is registered)
+	// This provides defense-in-depth - if the inner defer's recovery fails, this catches it
 	defer func() {
 		if r := recover(); r != nil {
-			log.Printf("[WARN] goFdwExplainForeignScan failed with panic: %v", r)
+			log.Printf("[WARN] goFdwBeginForeignScan failed with panic during early init: %v", r)
 			FdwError(fmt.Errorf("%v", r))
 		}
 	}()
@@ -285,6 +287,7 @@ func goFdwBeginForeignScan(node *C.ForeignScanState, eflags C.int) {
 
 	log.Printf("[INFO] goFdwBeginForeignScan, connection '%s', table '%s', explain: %v \n", opts["connection"], opts["table"], explain)
 
+	// Inner recover: catches panics during main scan processing
 	defer func() {
 		if r := recover(); r != nil {
 			log.Printf("[WARN] goFdwBeginForeignScan failed with panic: %v", r)

helpers.go

@@ -154,7 +154,11 @@ func ValToDatum(val interface{}, cinfo *C.ConversionInfo, buffer C.StringInfo) (
 		}
 	}()
 	// init an empty return result
-	datum := C.fdw_cStringGetDatum(C.CString(""))
+	// Allocate CString, use it, then immediately free to avoid memory leak
+	// Using explicit C.free() instead of defer because this is a hot path
+	emptyStr := C.CString("")
+	datum := C.fdw_cStringGetDatum(emptyStr)
+	C.free(unsafe.Pointer(emptyStr))
 
 	// write value into C buffer
 	if err := valToBuffer(val, cinfo.atttypoid, buffer); err != nil {
@@ -197,7 +201,12 @@ func valToBuffer(val interface{}, oid C.Oid, buffer C.StringInfo) (err error) {
 	}
 
 	C.resetStringInfo(buffer)
-	C.fdw_appendBinaryStringInfo(buffer, C.CString(valueString), C.int(len(valueString)))
+	// Allocate CString, use it, then immediately free to avoid memory leak
+	// Using explicit C.free() instead of defer because this is a hot path
+	// called for every string column in every row
+	cValueString := C.CString(valueString)
+	C.fdw_appendBinaryStringInfo(buffer, cValueString, C.int(len(valueString)))
+	C.free(unsafe.Pointer(cValueString))
 	return
 }
 

schema.go

@@ -66,7 +66,13 @@ func SchemaToSql(schema map[string]*proto.TableSchema, stmt *C.ImportForeignSche
 		}
 
 		log.Printf("[TRACE] SQL %s", sql)
-		commands = C.lappend(commands, unsafe.Pointer(C.CString(sql)))
+		// Use pstrdup to allocate in PostgreSQL memory context.
+		// This ensures the string is freed when the memory context is destroyed,
+		// avoiding a memory leak from C.CString which allocates on the C heap.
+		cSql := C.CString(sql)
+		pSql := C.pstrdup(cSql)
+		C.free(unsafe.Pointer(cSql))
+		commands = C.lappend(commands, unsafe.Pointer(pSql))
 	}
 
 	return commands