[OE-core] [PATCH 1/1] fetch2/__init__.py: add an "auto" policy for BB_SRCREV_POLICY

[Robert Yang]

The newly added "auto" policy is used for the SRCREV="${AUTOREV}" recipe,
the current BB_SRCREV_POLICY are: "clear" (default) and "cache":

* When "clear", the "AUTOREV" recipe will not be cached in bb_cache.dat

* When "cache", the "AUTOREV" would be cached in bb_cache.dat, but it
  doesn't try to get the latest revision.

The "auto" policy is much like the "cache" except that it will try to
get the latest revision.

[YOCTO #2920]

Signed-off-by: Jason Wessel <jason.wessel at windriver.com>
Signed-off-by: Robert Yang <liezhi.yang at windriver.com>
---
 bitbake/lib/bb/fetch2/__init__.py |   12 +++++++++---
 1 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/bitbake/lib/bb/fetch2/__init__.py b/bitbake/lib/bb/fetch2/__init__.py
index 12ebce2..27b73c0 100644
--- a/bitbake/lib/bb/fetch2/__init__.py
+++ b/bitbake/lib/bb/fetch2/__init__.py
@@ -249,8 +249,8 @@ def fetcher_init(d):
     Calls before this must not hit the cache.
     """
     # When to drop SCM head revisions controlled by user policy
-    srcrev_policy = d.getVar('BB_SRCREV_POLICY', True) or "clear"
-    if srcrev_policy == "cache":
+    srcrev_policy = get_srcrev_policy(d)
+    if srcrev_policy == "cache" or srcrev_policy == "auto":
         logger.debug(1, "Keeping SRCREV cache due to cache policy of: %s", srcrev_policy)
     elif srcrev_policy == "clear":
         logger.debug(1, "Clearing SRCREV cache due to cache policy of: %s", srcrev_policy)
@@ -384,9 +384,13 @@ def subprocess_setup():
     # SIGPIPE errors are known issues with gzip/bash
     signal.signal(signal.SIGPIPE, signal.SIG_DFL)
 
+def get_srcrev_policy(d):
+    return d.getVar('BB_SRCREV_POLICY', True) or "auto"
+
 def get_autorev(d):
     #  only not cache src rev in autorev case
-    if d.getVar('BB_SRCREV_POLICY', True) != "cache":
+    srcrev_policy = get_srcrev_policy(d)
+    if srcrev_policy != "cache" and srcrev_policy != "auto":
         d.setVar('__BB_DONT_CACHE', '1')
     return "AUTOINC"
 
@@ -1048,6 +1052,8 @@ class FetchMethod(object):
 
         revs = bb.persist_data.persist('BB_URI_HEADREVS', d)
         key = self.generate_revision_key(url, ud, d, name)
+        if get_srcrev_policy(d) == "auto":
+            revs[key] = self._latest_revision(url, ud, d, name)
         try:
             return revs[key]
         except KeyError:
-- 
1.7.1