[QGIS-Developer] Can't find SAGA devel versions after r413c6e5

[Rainer Hurling]

I forgot to mention, that if only FreeBSD users should have the problem 
with newer SAGA GIS versions and not having an LTR version, a local 
patch in the FreeBSD port is also conceivable.

Something like the following patches makes the processing tools for SAGA 
GIS, newer than version 2.3.x, 'functional' again on FreeBSD:


--- python/plugins/processing/algs/saga/SagaUtils.py.orig	2017-06-06 
19:35:06.000000000 +0200
+++ python/plugins/processing/algs/saga/SagaUtils.py	2017-06-08 
10:49:02.387866000 +0200
@@ -26,6 +26,7 @@
  __revision__ = '$Format:%H$'

  import os
+import platform
  import stat
  import subprocess
  import time
@@ -57,7 +58,7 @@

  def findSagaFolder():
      folder = None
-    if isMac():
+    if isMac() or platform.system() == 'FreeBSD':
          testfolder = os.path.join(QgsApplication.prefixPath(), 'bin')
          if os.path.exists(os.path.join(testfolder, 'saga_cmd')):
              folder = testfolder
@@ -82,7 +83,7 @@


  def sagaPath():
-    if not isWindows() and not isMac():
+    if not isWindows() and not isMac() and not platform.system() == 
'FreeBSD':
          return ''

      folder = findSagaFolder()
@@ -101,7 +102,7 @@
          fout.write('set SAGA_MLB=' + sagaPath() + os.sep +
                     'modules' + '\n')
          fout.write('PATH=%PATH%;%SAGA%;%SAGA_MLB%\n')
-    elif isMac():
+    elif isMac()  or platform.system() == 'FreeBSD':
          fout.write('export SAGA_MLB=' + sagaPath() +
                     '/../lib/saga\n')
          fout.write('export PATH=' + sagaPath() + ':$PATH\n')
@@ -130,7 +131,7 @@

      if isWindows():
          commands = [os.path.join(sagaPath(), "saga_cmd.exe"), "-v"]
-    elif isMac():
+    elif isMac() or platform.system() == 'FreeBSD':
          commands = [os.path.join(sagaPath(), "saga_cmd -v")]
      else:
          # for Linux use just one string instead of separated 
parameters as the list
@@ -146,7 +147,7 @@
              stderr=subprocess.STDOUT,
              universal_newlines=True,
          ).stdout
-        if isMac():  # This trick avoids having an uninterrupted system 
call exception if SAGA is not installed
+        if isMac() or platform.system() == 'FreeBSD':  # This trick 
avoids having an uninterrupted system call exception if SAGA is not 
installed
              time.sleep(1)
          try:
              lines = proc.readlines()


--- python/plugins/processing/algs/saga/SagaAlgorithmProvider.py.orig 
2017-06-08 02:16:08.000000000 +0200
+++ python/plugins/processing/algs/saga/SagaAlgorithmProvider.py 
2017-06-08 11:15:09.732518000 +0200
@@ -73,7 +73,7 @@
                                     self.tr('Problem with SAGA 
installation: SAGA was not found or is not correctly installed'))
              return

-        if not version.startswith('2.3.'):
+        if version < '2.3.':
              ProcessingLog.addToLog(ProcessingLog.LOG_ERROR,
                                     self.tr('Problem with SAGA 
installation: unsupported SAGA version found.'))
              return


Am 08.06.2017 um 11:42 schrieb Rainer Hurling:
> Hi Alex,
> 
> Thanks for the quick and detailed answer.
> 
> Am 08.06.2017 um 11:29 schrieb Alexander Bruy:
>> Hi Rainer,
>>
>> 2017-06-08 10:24 GMT+03:00 Rainer Hurling <rhurlin at gwdg.de>:
>>> For some reasons, we don't package our system with different versions of
>>> SAGA GIS. Recent FreeBSD comes with SAGA GIS version 3.0.0, I am 
>>> working on
>>> an update to version 4.1.0.
>>>
>>> With your latest updates to QGIS (r413c6e5), newer versions of SAGA 
>>> GIS than
>>> 2.3.x are not recognized any more :(
>>>
>>> I am familiar with the background, that QGIS processing only 
>>> garantees to
>>> work well with the SAGA GIS LTR version. But there was a kind of tacit
>>> agreement for several years now, that QGIS processing tools also 
>>> accepted to
>>> display (and somewhat work with) newer SAGA GIS versions.
>>
>> Previously QGIS Processing supported multiple SAGA versions, but as SAGA
>> devs often changed API even between minor versions it was a real pain to
>> maintain compatibility and provide users with robust and working SAGA 
>> inteface.
>> Because for each change in SAGA API we need not only update algorithms
>> descriptions but also add some workaronds in the Processing source code.
>>
>> After release of SAGA LTR we had several long discussions and finally 
>> decided
>> that better to have good support for single SAGA version that multiple 
>> partially
>> broken version. That's why support for all other versions was removed. 
>> We also
>> removed option to choose another SAGA installation, as this makes no 
>> sense
>> now and can lead to confusion in case when user select unsupported SAGA
>> version.
>>
> 
> In principle I understand this point of view, but it makes it relatively 
> difficult to identify the necessary changes for newer SAGA GIS versions.
> 
> And as I outlined before, there are constraints on some OS for the 
> presence of newer SAGA GIS versions. In the past, the QGIS user was able 
> to use most of the SAGA GIS functions, as only some of the functions had 
> bigger API changes.
> 
>>> Now my request: It would be fine and at least important for FreeBSD 
>>> users,
>>> to have the possibility to use SAGA GIS > 2.3.x with QGIS 2.18.9 again.
>>
>> I'm afrad this is not possible, as we have no resources to keep 
>> algorithms
>> descriptions and, more importantly, source code updated with numerous 
>> SAGA
>> API breaks in every SAGA release.
>>
>> As an option I can suggest to create altenate SAGA provider plugin 
>> which will
>> support non-LTR SAGA versions.
>>
>>
> 
> This would be a very nice option to have such an additional support. A 
> provider plugin for (newer) non-LTR SAGA versions could throw a 
> warnings, that this SAGA GIS version is not fully supported and the user 
> has to expect problems ...