bitbake: fetch2: Add autorev warning when it is set too late

Bitbake expects a consistent metadata environment when it parses. There
are plenty of ways you can set a recipe to autorev at a point where parts
of the fetcher have already been triggered leading to obsure bugs which
I struggled to debug, let alone anyone not familar with the code.

If anyone is running into the message from the commit, the issue is
likely one of timing. Keep in mind that the anonymous python code
in base.bbclass will expand variables like FILESPATH, WORKDIR and others
which contain PV. The recipe needs to be set to AUTOREV before that
anonymous python runs.

In particular, that means you can't set SRCREV = "${AUTOREV}" in other
anonymous python, it needs to happen earlier.

(Bitbake rev: 4d9ec332d5bfc8b60b54f8ec2a17d34e35aa903a)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/fetch2/__init__.py

@@ -749,10 +749,13 @@ def subprocess_setup():
     # SIGPIPE errors are known issues with gzip/bash
     signal.signal(signal.SIGPIPE, signal.SIG_DFL)
 
-def get_autorev(d):
-    #  only not cache src rev in autorev case
+def mark_recipe_nocache(d):
     if d.getVar('BB_SRCREV_POLICY') != "cache":
         d.setVar('BB_DONT_CACHE', '1')
+
+def get_autorev(d):
+    mark_recipe_nocache(d)
+    d.setVar("__BBAUTOREV_SEEN", True)
     return "AUTOINC"
 
 def get_srcrev(d, method_name='sortable_revision'):
@@ -1219,6 +1222,7 @@ def srcrev_internal_helper(ud, d, name):
     if srcrev == "INVALID" or not srcrev:
         raise FetchError("Please set a valid SRCREV for url %s (possible key names are %s, or use a ;rev=X URL parameter)" % (str(attempts), ud.url), ud.url)
     if srcrev == "AUTOINC":
+        d.setVar("__BBAUTOREV_ACTED_UPON", True)
         srcrev = ud.method.latest_revision(ud, d, name)
 
     return srcrev

bitbake/lib/bb/fetch2/git.py

@@ -737,7 +737,7 @@ class Git(FetchMethod):
             raise bb.fetch2.FetchError("Recipe uses a floating tag/branch '%s' for repo '%s' without a fixed SRCREV yet doesn't call bb.fetch2.get_srcrev() (use SRCPV in PV for OE)." % (ud.unresolvedrev[name], ud.host+ud.path))
 
         # Ensure we mark as not cached
-        bb.fetch2.get_autorev(d)
+        bb.fetch2.mark_recipe_nocache(d)
 
         output = self._lsremote(ud, d, "")
         # Tags of the form ^{} may not work, need to fallback to other form

bitbake/lib/bb/parse/ast.py

@@ -400,6 +400,9 @@ def finalize(fn, d, variant = None):
 
         d.setVar('BBINCLUDED', bb.parse.get_file_depends(d))
 
+        if d.getVar('__BBAUTOREV_SEEN') and d.getVar('__BBSRCREV_SEEN') and not d.getVar("__BBAUTOREV_ACTED_UPON"):
+            bb.fatal("AUTOREV/SRCPV set too late for the fetcher to work properly, please set the variables earlier in parsing. Erroring instead of later obtuse build failures.")
+
         bb.event.fire(bb.event.RecipeParsed(fn), d)
     finally:
         bb.event.set_handlers(saved_handlers)