python-smartpm: Don't ignore error if RPM transaction fails without problems

SmartPM could misinterpret RPM transaction error as success,
if ts.run() (RPM Python API) returns an empty problems list.

This could happen for example if the RPM database is partially corrupted
such that the transaction does not have any problems like conflicts or
missing dependencies, but still can't be committed.

The added patch fixes the problem in the upstream sources;
one of the existing patches has to be adjusted to still apply.

Signed-off-by: Daniel Klauer <daniel.klauer@gin.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

3 files changed, 61 insertions, 3 deletions

diff --git a/meta/recipes-devtools/python/python-smartpm/smart-attempt.patch b/meta/recipes-devtools/python/python-smartpm/smart-attempt.patch
index ec98e03c0a..5aedc88266 100644
--- a/meta/recipes-devtools/python/python-smartpm/smart-attempt.patch
+++ b/meta/recipes-devtools/python/python-smartpm/smart-attempt.patch
@@ -36,7 +36,7 @@ index 9bbd952..ba6405a 100644
          finally:
              del getTS.ts
              cb.grabOutput(False)
-+            if probs and sysconf.has("attempt-install", soft=True):
++            if (probs is not None) and sysconf.has("attempt-install", soft=True):
 +                def remove_conflict(pkgNEVR):
 +                    for key in changeset.keys():
 +                        if pkgNEVR == str(key):
@@ -67,8 +67,8 @@ index 9bbd952..ba6405a 100644
 +                        retry = 0
 +
              prog.setDone()
--            if probs:
-+            if probs and (not retry):
+-            if probs is not None:
++            if (probs is not None) and (not retry):
                  raise Error, "\n".join([x[0] for x in probs])
              prog.stop()
 +            if retry and len(changeset):
diff --git a/meta/recipes-devtools/python/python-smartpm/smart-rpm-transaction-failure-check.patch b/meta/recipes-devtools/python/python-smartpm/smart-rpm-transaction-failure-check.patch
new file mode 100644
index 0000000000..bb8c3afdb7
--- /dev/null
+++ b/meta/recipes-devtools/python/python-smartpm/smart-rpm-transaction-failure-check.patch
@@ -0,0 +1,57 @@
+From 0c55d7e18f40465e95e8e4bf22af01f5d4477d3c Mon Sep 17 00:00:00 2001
+From: Daniel Klauer <daniel.klauer@gin.de>
+Date: Wed, 11 May 2016 17:22:49 +0200
+Subject: [PATCH] rpm: Don't ignore transaction error with empty problems list
+
+SmartPM could misinterpret RPM transaction error as success,
+if ts.run() (RPM Python API) returns an empty problems list,
+because of incorrect check for None which treated empty list
+to be the same as None when it has different meaning.
+
+ts.run() returns:
+* None in case of success
+* problems list in case of error, may be empty
+(look at rpmts_Run() in rpm-5.4.14/python/rpmts-py.c [1])
+
+"if mylist" is not good enough to check for error here, because it will
+treat an empty list as "false" because its len() == 0 [2].
+
+ts.check() seems to be different (it's ok for it to return an empty list),
+but for consistency it should be made clear that it can return either None,
+an empty list or a non-empty list.
+
+[1] http://rpm5.org/cvs/fileview?f=rpm/python/rpmts-py.c&v=1.111.2.3
+[2] https://docs.python.org/2/library/stdtypes.html#truth-value-testing
+
+Upstream-Status: Pending
+
+Signed-off-by: Daniel Klauer <daniel.klauer@gin.de>
+---
+ smart/backends/rpm/pm.py | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/smart/backends/rpm/pm.py b/smart/backends/rpm/pm.py
+index 9bbd952..635f726 100644
+--- a/smart/backends/rpm/pm.py
++++ b/smart/backends/rpm/pm.py
+@@ -208,7 +208,7 @@ class RPMPackageManager(PackageManager):
+         force = sysconf.get("rpm-force", False)
+         if not force:
+             probs = ts.check()
+-            if probs:
++            if (probs is not None) and (len(probs) != 0):
+                 problines = []
+                 for prob in probs:
+                     name1 = "%s-%s-%s" % prob[0]
+@@ -247,7 +247,7 @@ class RPMPackageManager(PackageManager):
+             del getTS.ts
+             cb.grabOutput(False)
+             prog.setDone()
+-            if probs:
++            if probs is not None:
+                 raise Error, "\n".join([x[0] for x in probs])
+             prog.stop()
+
+--
+1.9.1
+
diff --git a/meta/recipes-devtools/python/python-smartpm_git.bb b/meta/recipes-devtools/python/python-smartpm_git.bb
index f030b3eb37..0d37dae3cb 100644
--- a/meta/recipes-devtools/python/python-smartpm_git.bb
+++ b/meta/recipes-devtools/python/python-smartpm_git.bb
@@ -17,6 +17,7 @@ SRC_URI = "\
           file://smart-recommends.patch \
           file://smart-improve-error-reporting.patch \
           file://smart-channelsdir.patch \
+          file://smart-rpm-transaction-failure-check.patch \
           file://smart-attempt.patch \
           file://smart-attempt-fix.patch \
           file://smart-add-for-rpm-ignoresize-check.patch \