From https://gitlab.com/inkscape/inkscape/-/merge_requests/7264

From 97bd8f29a61e691ceea98ca2444b974cf4256ae0 Mon Sep 17 00:00:00 2001
From: Rafael Siejakowski <rs@rs-math.net>
Date: Sun, 8 Jun 2025 21:30:44 +0200
Subject: [PATCH] Fix build against Poppler 25.06

Accommodate for the private API change, whereby an array of pointers
has been replaced with a vector of unique_ptr.

Backported from MR 7261
https://gitlab.com/inkscape/inkscape/-/merge_requests/7261

Fixes https://gitlab.com/inkscape/inkscape/-/issues/5836
---
 .../internal/pdfinput/pdf-parser.cpp          | 23 +++++++++++--------
 .../pdfinput/poppler-transition-api.h         | 12 ++++++++++
 2 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/src/extension/internal/pdfinput/pdf-parser.cpp b/src/extension/internal/pdfinput/pdf-parser.cpp
index 01d7bf6ef0e..0d31eda16f4 100644
--- a/src/extension/internal/pdfinput/pdf-parser.cpp
+++ b/src/extension/internal/pdfinput/pdf-parser.cpp
@@ -27,6 +27,7 @@
 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
+#include <memory>
 #include <mutex> // std::call_once()
 #include <utility>
 #include <vector>
@@ -686,7 +687,6 @@ void PdfParser::opSetLineWidth(Object args[], int /*numArgs*/)
 void PdfParser::opSetExtGState(Object args[], int /*numArgs*/)
 {
     Object obj1, obj2, obj3, obj4, obj5;
-    Function *funcs[4] = {nullptr, nullptr, nullptr, nullptr};
     GfxColor backdropColor;
     GBool haveBackdropColor = gFalse;
     GBool alpha = gFalse;
@@ -744,13 +744,14 @@ void PdfParser::opSetExtGState(Object args[], int /*numArgs*/)
         state->setLineWidth(obj2.getNum());
     }
 
+    _POPPLER_DECLARE_TRANSFER_FUNCTION_VECTOR(funcs);
+
     // transfer function
     if (_POPPLER_CALL_ARGS_DEREF(obj2, obj1.dictLookup, "TR2").isNull()) {
         _POPPLER_CALL_ARGS(obj2, obj1.dictLookup, "TR");
     }
     if (obj2.isName(const_cast<char *>("Default")) || obj2.isName(const_cast<char *>("Identity"))) {
-        funcs[0] = funcs[1] = funcs[2] = funcs[3] = nullptr;
-        state->setTransfer(funcs);
+        state->setTransfer(std::move(funcs));
     } else if (obj2.isArray() && obj2.arrayGetLength() == 4) {
         int pos = 4;
         for (int i = 0; i < 4; ++i) {
@@ -763,12 +764,14 @@ void PdfParser::opSetExtGState(Object args[], int /*numArgs*/)
         }
         _POPPLER_FREE(obj3);
         if (pos == 4) {
-            state->setTransfer(funcs);
+            state->setTransfer(std::move(funcs));
         }
     } else if (obj2.isName() || obj2.isDict() || obj2.isStream()) {
         if ((funcs[0] = Function::parse(&obj2))) {
-            funcs[1] = funcs[2] = funcs[3] = nullptr;
-            state->setTransfer(funcs);
+            funcs[1] = nullptr;
+            funcs[2] = nullptr;
+            funcs[3] = nullptr;
+            state->setTransfer(std::move(funcs));
         }
     } else if (!obj2.isNull()) {
         error(errSyntaxError, getPos(), "Invalid transfer function in ExtGState");
@@ -790,8 +793,7 @@ void PdfParser::opSetExtGState(Object args[], int /*numArgs*/)
                 funcs[0] = Function::parse(&obj3);
                 if (funcs[0]->getInputSize() != 1 || funcs[0]->getOutputSize() != 1) {
                     error(errSyntaxError, getPos(), "Invalid transfer function in soft mask in ExtGState");
-                    delete funcs[0];
-                    funcs[0] = nullptr;
+                    _POPPLER_DELETE_TRANSFER_FUNCTION(funcs[0]);
                 }
             }
             _POPPLER_FREE(obj3);
@@ -835,9 +837,10 @@ void PdfParser::opSetExtGState(Object args[], int /*numArgs*/)
                             }
                         }
                     }
-                    doSoftMask(&obj3, alpha, blendingColorSpace.get(), isolated, knockout, funcs[0], &backdropColor);
+                    doSoftMask(&obj3, alpha, blendingColorSpace.get(), isolated, knockout,
+                               _POPPLER_GET_TRANSFER_FUNCTION_POINTER(funcs[0]), &backdropColor);
                     if (funcs[0]) {
-                        delete funcs[0];
+                        _POPPLER_DELETE_TRANSFER_FUNCTION(funcs[0]);
                     }
                 } else {
                     error(errSyntaxError, getPos(), "Invalid soft mask in ExtGState - missing group");
diff --git a/src/extension/internal/pdfinput/poppler-transition-api.h b/src/extension/internal/pdfinput/poppler-transition-api.h
index a67132ba6bd..d04412757bc 100644
--- a/src/extension/internal/pdfinput/poppler-transition-api.h
+++ b/src/extension/internal/pdfinput/poppler-transition-api.h
@@ -15,6 +15,18 @@
 #include <glib/poppler-features.h>
 #include <poppler/UTF.h>
 
+#if POPPLER_CHECK_VERSION(25, 6, 0)
+#define _POPPLER_DECLARE_TRANSFER_FUNCTION_VECTOR(name) std::vector<std::unique_ptr<Function>> name(4)
+#define _POPPLER_DELETE_TRANSFER_FUNCTION(name) name.reset()
+#define _POPPLER_GET_TRANSFER_FUNCTION_POINTER(name) name.get()
+#else
+#define _POPPLER_DECLARE_TRANSFER_FUNCTION_VECTOR(name) Function *name[4] = {}
+#define _POPPLER_DELETE_TRANSFER_FUNCTION(name) \
+    delete name;                                \
+    name = nullptr
+#define _POPPLER_GET_TRANSFER_FUNCTION_POINTER(name) name
+#endif
+
 #if POPPLER_CHECK_VERSION(25,2,0)
 #define _POPPLER_GET_CODE_TO_GID_MAP(ff, len) getCodeToGIDMap(ff)
 #define _POPPLER_GET_CID_TO_GID_MAP(len) getCIDToGIDMap()
-- 
GitLab