Add option to chose python version for building 5.15 WebEngine

[ChangeLog] Adds the configure option --webengine-python-version to
allow the user to select the python version for building.

Valid options are python2 or python3. The default version will continue
to be Python 2.

Fixes: QTBUG-117693
Change-Id: Ie12ce78d1d81c49a2c46acc4160c13f766d56fe7
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

6 files changed, 45 insertions, 30 deletions

diff --git a/config_help.txt b/config_help.txt
index 48236c18a..d50892121 100644
--- a/config_help.txt
+++ b/config_help.txt
@@ -15,6 +15,7 @@ WebEngine options:
                                    (Linux only)
   -webengine-pepper-plugins ...... Enable use of Pepper Flash and Widevine
                                    plugins [auto]
+  -webengine-python-version ...... Use specific python version for building [python2/python3]
   -webengine-printing-and-pdf .... Enable use of printing and output to PDF
                                    [auto]
   -webengine-proprietary-codecs .. Enable support for proprietary codecs [no]
diff --git a/configure.pri b/configure.pri
index 3a33bdc82..99cdbf72b 100644
--- a/configure.pri
+++ b/configure.pri
@@ -12,12 +12,9 @@ defineTest(isPythonVersionSupported) {
     python_version ~= s/[()]//g
     python_version = $$split(python_version, ',')
     python_major_version = $$first(python_version)
-    greaterThan(python_major_version, 2) {
-        qtLog("Python version 3 is not supported by Chromium.")
-        return(false)
-    }
     python_minor_version = $$member(python_version, 1)
     python_patch_version = $$member(python_version, 2)
+    greaterThan(python_major_version, 2): greaterThan(python_minor_version, 7): return(true)
     greaterThan(python_major_version, 1): greaterThan(python_minor_version, 6): greaterThan(python_patch_version, 4): return(true)
     qtLog("Unsupported python version: $${python_major_version}.$${python_minor_version}.$${python_patch_version}.")
     return(false)
@@ -52,22 +49,38 @@ defineTest(qtConfReport_jumboBuild) {
     qtConfReportPadded($${1}, $$mergeLimit)
 }
 
-defineTest(qtConfTest_detectPython2) {
-    python = $$qtConfFindInPath("python2$$EXE_SUFFIX")
-    isEmpty(python) {
-        qtLog("'python2$$EXE_SUFFIX' not found in PATH. Checking for 'python$$EXE_SUFFIX'.")
-        python = $$qtConfFindInPath("python$$EXE_SUFFIX")
+defineTest(qtConfTest_detectPython) {
+    pythonOverride = $$eval(config.input.python_override)
+    !isEmpty(pythonOverride) {
+        python = $$qtConfFindInPath("$$pythonOverride$$EXE_SUFFIX")
+        isEmpty(python) {
+           qtLog("User selected '$$pythonOverride$$EXE_SUFFIX' was not found in PATH. Giving up.")
+           return(false)
+        }
     }
+
+    win32 {
+        # the default name of the python 2 executable on windows is just
+        # python, so try that first
+        isEmpty(python):python = $$qtConfFindInPath("python$$EXE_SUFFIX")
+        isEmpty(python):python = $$qtConfFindInPath("python2$$EXE_SUFFIX")
+        isEmpty(python):python = $$qtConfFindInPath("python3$$EXE_SUFFIX")
+    } else {
+        isEmpty(python):python = $$qtConfFindInPath("python2$$EXE_SUFFIX")
+        isEmpty(python):python = $$qtConfFindInPath("python3$$EXE_SUFFIX")
+        isEmpty(python):python = $$qtConfFindInPath("python$$EXE_SUFFIX")
+    }
+
     isEmpty(python) {
-        qtLog("'python$$EXE_SUFFIX' not found in PATH. Giving up.")
+        qtLog("Python not found in PATH. Giving up.")
         return(false)
     }
     !isPythonVersionSupported($$python) {
-        qtLog("A suitable Python 2 executable could not be located.")
+        qtLog("A suitable Python executable could not be located.")
         return(false)
     }
 
-    # Make tests.python2.location available in configure.json.
+    # Make tests.python.location available in configure.json.
     $${1}.location = $$clean_path($$python)
     export($${1}.location)
     $${1}.cache += location
diff --git a/mkspecs/features/functions.prf b/mkspecs/features/functions.prf
index 7f630588a..65500776b 100644
--- a/mkspecs/features/functions.prf
+++ b/mkspecs/features/functions.prf
@@ -44,11 +44,11 @@ defineReplace(which) {
 
 # Returns the unquoted path to the python executable.
 defineReplace(pythonPath) {
-    isEmpty(QMAKE_PYTHON2) {
+    isEmpty(QMAKE_PYTHON) {
         # Fallback for building QtWebEngine with Qt < 5.8
-        QMAKE_PYTHON2 = python
+        QMAKE_PYTHON = python
     }
-    return($$QMAKE_PYTHON2)
+    return($$QMAKE_PYTHON)
 }
 
 # Returns the python executable for use with shell / make targets.
diff --git a/src/3rdparty b/src/3rdparty
-Subproject 38655f07d8ef13eb067e3a29bb3a0c2dc0b1971
+Subproject 68302c9ea158fbc83cd28570a0560e5a892b45e
diff --git a/src/buildtools/config/support.pri b/src/buildtools/config/support.pri
index e7f869a15..a9df3d243 100644
--- a/src/buildtools/config/support.pri
+++ b/src/buildtools/config/support.pri
@@ -21,7 +21,7 @@ defineReplace(qtwebengine_checkWebEngineCoreError) {
     !qtwebengine_checkForGperf(QtWebEngine):return(false)
     !qtwebengine_checkForBison(QtWebEngine):return(false)
     !qtwebengine_checkForFlex(QtWebEngine):return(false)
-    !qtwebengine_checkForPython2(QtWebEngine):return(false)
+    !qtwebengine_checkForPython(QtWebEngine):return(false)
     !qtwebengine_checkForNodejs(QtWebEngine):return(false)
     !qtwebengine_checkForSanitizer(QtWebEngine):return(false)
     linux:!qtwebengine_checkForPkgCfg(QtWebEngine):return(false)
@@ -51,7 +51,7 @@ defineReplace(qtwebengine_checkPdfError) {
     !qtwebengine_checkForGperf(QtPdf):return(false)
     !qtwebengine_checkForBison(QtPdf):return(false)
     !qtwebengine_checkForFlex(QtPdf):return(false)
-    !qtwebengine_checkForPython2(QtPdf):return(false)
+    !qtwebengine_checkForPython(QtPdf):return(false)
     !qtwebengine_checkForSanitizer(QtPdf):return(false)
     linux:!qtwebengine_checkForPkgCfg(QtPdf):return(false)
     linux:!qtwebengine_checkForHostPkgCfg(QtPdf):return(false)
@@ -143,10 +143,10 @@ defineTest(qtwebengine_checkForFlex) {
     return(true)
 }
 
-defineTest(qtwebengine_checkForPython2) {
+defineTest(qtwebengine_checkForPython) {
     module = $$1
-    !qtConfig(webengine-python2) {
-        qtwebengine_skipBuild("Python version 2 (2.7.5 or later) is required to build $${module}.")
+    !qtConfig(webengine-python) {
+        qtwebengine_skipBuild("Python version 2 (2.7.5 or later) or Python version 3 (3.6 or later) is required to build $${module}.")
         return(false)
     }
     return(true)
diff --git a/src/buildtools/configure.json b/src/buildtools/configure.json
index 9e7a0c570..17fc65106 100644
--- a/src/buildtools/configure.json
+++ b/src/buildtools/configure.json
@@ -10,7 +10,8 @@
         "options": {
             "build-qtwebengine-core": "boolean",
             "build-qtpdf": "boolean",
-            "webengine-jumbo-build": { "type": "optionalString", "name": "merge_limit"}
+            "webengine-jumbo-build": { "type": "optionalString", "name": "merge_limit"},
+            "webengine-python-version": { "type": "optionalString", "name": "python_override", "values": ["python2", "python3"] }
         }
     },
     "libraries": {
@@ -316,9 +317,9 @@
             "label": "system ninja",
             "type": "detectNinja"
         },
-        "webengine-python2": {
-            "label": "python2",
-            "type": "detectPython2",
+        "webengine-python": {
+            "label": "python",
+            "type": "detectPython",
             "log": "location"
         },
         "webengine-winversion": {
@@ -395,7 +396,7 @@
                          && features.webengine-gperf
                          && features.webengine-bison
                          && features.webengine-flex
-                         && features.webengine-python2
+                         && features.webengine-python
                          && features.webengine-nodejs
                          && (!config.sanitizer || features.webengine-sanitizer)
                          && (!config.linux || features.pkg-config)
@@ -421,7 +422,7 @@
                          && features.webengine-gperf
                          && features.webengine-bison
                          && features.webengine-flex
-                         && features.webengine-python2
+                         && features.webengine-python
                          && (!config.sanitizer || features.webengine-sanitizer)
                          && (!config.linux || features.pkg-config)
                          && (!config.linux || features.webengine-host-pkg-config)
@@ -444,12 +445,12 @@
             "autoDetect": "features.private_tests",
             "output": [ "privateFeature" ]
         },
-        "webengine-python2": {
-            "label": "python2",
-            "condition": "tests.webengine-python2",
+        "webengine-python": {
+            "label": "python",
+            "condition": "tests.webengine-python",
             "output": [
                 "privateFeature",
-                { "type": "varAssign", "name": "QMAKE_PYTHON2", "value": "tests.webengine-python2.location" }
+                { "type": "varAssign", "name": "QMAKE_PYTHON", "value": "tests.webengine-python.location" }
             ]
         },
         "webengine-gperf": {