From 5fa823491b3f1a3d6f8161639686a0fbc33e6f03 Mon Sep 17 00:00:00 2001
From: Alexandru Croitor <alexandru.croitor@qt.io>
Date: Thu, 22 Oct 2020 17:23:46 +0200
Subject: [PATCH] CMake: Fix automatic sysrootification detection for qmake

The way we detected whether SysrootifyPrefix needs to be set was
incorrect.

We checked if extprefix == prefix => SysrootifyPrefix should be
true. But that was previously always the case for a non-prefix build,
which means it was not possible to build apps (due to qmake expecting
to find include dirs in the sysroot, despite the non-prefix Qt not
being installed anywhere into the sysroot).

Instead we should do what qmake does. Only set SysrootifyPrefix to
true if extprefix was not provided and a sysroot is available.

To make it work for iOS and Android, the sysroot detection code had to
be moved earlier than the SysrootifyPrefix detection.

Task-number: QTBUG-86053
Change-Id: Idcc1260a675fb2ef9ae27fc9dc42a68b30f763b8
Reviewed-by: Cristian Adam <cristian.adam@qt.io>
---
 cmake/QtQmakeHelpers.cmake | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/cmake/QtQmakeHelpers.cmake b/cmake/QtQmakeHelpers.cmake
index a75fc6f13a7..dae5af8db96 100644
--- a/cmake/QtQmakeHelpers.cmake
+++ b/cmake/QtQmakeHelpers.cmake
@@ -112,7 +112,21 @@ function(qt_generate_qmake_wrapper_for_target)
     file(RELATIVE_PATH ext_prefix_relative_to_host_prefix "${host_prefix}" "${ext_prefix}")
 
     set(content "")
-    if(ext_prefix STREQUAL prefix)
+
+    # On Android CMAKE_SYSROOT is set, but from qmake's point of view it should not be set, because
+    # then qmake generates incorrect Qt module include flags (among other things). Do the same for
+    # darwin uikit cross-compilation.
+    set(sysroot "")
+    if(CMAKE_SYSROOT AND NOT ANDROID AND NOT UIKIT)
+        set(sysroot "${CMAKE_SYSROOT}")
+    endif()
+
+    # Detect if automatic sysrootification should happen. All of the following must be true:
+    # sysroot is set (CMAKE_SYSRROT)
+    # prefix is set (CMAKE_INSTALL_PREFIX)
+    # extprefix is explicitly NOT set (CMAKE_STAGING_PREFIX, not QT_STAGING_PREFIX because that
+    #                                  always ends up having a value)
+    if(NOT CMAKE_STAGING_PREFIX AND sysroot)
         set(sysrootify_prefix true)
     else()
         set(sysrootify_prefix false)
@@ -130,7 +144,7 @@ HostData=${CMAKE_CURRENT_SOURCE_DIR}
 
         # Set $$[QT_HOST_DATA/get] to avoid falling back to the source dir where it isn't explicitly
         # requested.
-        # Also make sure to specif the Prefix as well, because it doesn't get inherited from the
+        # Also make sure to specify the Prefix as well, because it doesn't get inherited from the
         # [Paths] section.
         string(APPEND content "[EffectivePaths]
 HostData=${ext_prefix}
@@ -138,14 +152,6 @@ Prefix=${ext_prefix_relative_to_conf_file}
 ")
     endif()
 
-    # On Android CMAKE_SYSROOT is set, but for Qt's purposes it should not be set, because then
-    # qmake generates incorrect Qt module include flags (among other things). Do the same for darwin
-    # cross-compilation.
-    set(sysroot "")
-    if(CMAKE_SYSROOT AND NOT ANDROID AND NOT UIKIT)
-        set(sysroot "${CMAKE_SYSROOT}")
-    endif()
-
     string(APPEND content
         "[Paths]
 Prefix=${ext_prefix_relative_to_conf_file}