[OE-core] [PATCH 0/2] Yocto Compatible 2.0 support code

[Patrick Ohly]

On Thu, 2017-06-08 at 21:31 +0200, Patrick Ohly wrote:
> On Thu, 2017-06-08 at 10:28 -0500, Joshua Watt wrote:
> > Sure. I wouldn't suggest using an if statement for "just anything", you
> > can surely do terrible things that way. It would (by convention) be
> > restricted to the same sorts of things that the conditional includes
> > allow now. On a similar token, you can do the same sorts of terrible
> > things with conditional includes as currently proposed because it has
> > the same enforcement policy (i.e. "by convention").
> 
> I'm starting to wonder whether this "convention" can be strengthened
> with additional warnings. The code which currently evaluates the include
> parameter could record in the datastore the original expression and what
> it evaluated to, then later when the recipe gets finalized, an event
> handler can check whether evaluating the expression still gives the same
> result.

Below is a quick-and-dirty proof of concept. Example bmap-tools_
%.bbappend:

        FOO = "bmap-tools-deploy.inc"
        require ${FOO}
        FOO = ""

Example warning:

WARNING: .../bmap-tools/bmap-tools_3.2.bb: .../bmap-tools_%.bbappend:2: include/require/inherit "${FOO}" resulted in including "bmap-tools-deploy.inc" while parsing. Variables effecting the parameter changed later such that nothing would have been included at the end of the recipe.

I found one false positive (LAYERDIR is set during parsing and unset
afterwards) which the code below filters out. 

I also get for all recipes (i.e. the error is in the base
configuration):

meta/conf/bitbake.conf:752: include/require/inherit "conf/target/${TARGET_SYS}.conf" resulted in including "conf/target/x86_64-oe-linux.conf" while parsing. Variables effecting the parameter changed later such that "conf/target/x86_64-refkit-linux.conf" would have been included at the end of the recipe.

None of these two files exist, so it doesn't make a difference. But is
it really intended that a conf/target/${TARGET_SYS}.conf gets included
that isn't the one for the final TARGET_SYS? That looks like a genuine
bug to me.

TARGET_SYS changes because TARGET_VENDOR gets set by the ${DISTRO}.conf,
which gets included later.

If we agree that such a message is useful, should it get added after
merging the proposed bitbake enhancements or together with them? Doing
it properly implies adding tests, and I do not have the time for that
now. I'd prefer to add the proposed patches first so that they can be
used, then add the warning before 2.4 gets released.

Should this warning be entirely in bitbake or should it become part of
OE's sanity.bbclass? The latter would have the advantage that it could
be configured as fatal error. The downside is that bitbake needs to
export data, which implies adding a semi-stable API.

Do we want some suppression mechanism? Something like:

require ${PARSE_TIME_EVALUATION}${FOO}

where PARSE_TIME_EVALUATION is unset, but can be checked for in the code
that normally would print the warning?

diff --git a/lib/bb/parse/ast.py b/lib/bb/parse/ast.py
index dba4540f5eb..91db56197f0 100644
--- a/lib/bb/parse/ast.py
+++ b/lib/bb/parse/ast.py
@@ -50,14 +50,13 @@ class IncludeNode(AstNode):
         """
         Include the file and evaluate the statements
         """
-        s = data.expand(self.what_file)
-        logger.debug(2, "CONF %s:%s: including %s", self.filename, self.lineno, s)
+        logger.debug(2, "CONF %s:%s: including %s = %s", self.filename, self.lineno, self.what_file, data.expand(self.what_file))
 
         # TODO: Cache those includes... maybe not here though
         if self.force:
-            bb.parse.ConfHandler.include(self.filename, s, self.lineno, data, "include required")
+            bb.parse.ConfHandler.include(self.filename, self.what_file, self.lineno, data, "include required")
         else:
-            bb.parse.ConfHandler.include(self.filename, s, self.lineno, data, False)
+            bb.parse.ConfHandler.include(self.filename, self.what_file, self.lineno, data, False)
 
 class ExportNode(AstNode):
     def __init__(self, filename, lineno, var):
@@ -362,6 +361,18 @@ def finalize(fn, d, variant = None):
 
     d.setVar('BBINCLUDED', bb.parse.get_file_depends(d))
 
+    parse_expansions = d.getVar('_PARSE_TIME_EXPANSIONS')
+    if parse_expansions:
+        def fns_name(fns):
+            if fns:
+                return '"%s"' % fns
+            else:
+                return 'nothing'
+        for parentfn, lineno, fns_unexpanded, fns in parse_expansions:
+            current_fns = d.expand(fns_unexpanded)
+            if fns != current_fns and '${LAYERDIR}' not in current_fns:
+                logger.warning('%s:%d: include/require/inherit "%s" resulted in including %s while parsing. Variables effecting the parameter changed later such that %s would have been included at the end of the recipe.' % (parentfn, lineno, fns_unexpanded, fns_name(fns), fns_name(current_fns)))
+
     bb.event.fire(bb.event.RecipeParsed(fn), d)
     bb.event.set_handlers(saved_handlers)
 
diff --git a/lib/bb/parse/parse_py/BBHandler.py b/lib/bb/parse/parse_py/BBHandler.py
index fe918a41f34..923d210a3e8 100644
--- a/lib/bb/parse/parse_py/BBHandler.py
+++ b/lib/bb/parse/parse_py/BBHandler.py
@@ -61,6 +61,7 @@ def supports(fn, d):
 def inherit(files, fn, lineno, d):
     __inherit_cache = d.getVar('__inherit_cache', False) or []
     files = d.expand(files).split()
+    # TODO: remember expansion result
     for file in files:
         if not os.path.isabs(file) and not file.endswith(".bbclass"):
             file = os.path.join('classes', '%s.bbclass' % file)
diff --git a/lib/bb/parse/parse_py/ConfHandler.py b/lib/bb/parse/parse_py/ConfHandler.py
index 97aa1304314..b4f0c61d256 100644
--- a/lib/bb/parse/parse_py/ConfHandler.py
+++ b/lib/bb/parse/parse_py/ConfHandler.py
@@ -75,8 +75,16 @@ def include(parentfn, fns, lineno, data, error_out):
     used in a ParseError that will be raised if the file to be included could
     not be included. Specify False to avoid raising an error in this case.
     """
+    fns_unexpanded = fns
     fns = data.expand(fns)
     parentfn = data.expand(parentfn)
+    parse_expansions = data.getVar('_PARSE_TIME_EXPANSIONS')
+    if parse_expansions is None:
+        parse_expansions = []
+    parse_expansions.append((parentfn, lineno, fns_unexpanded, fns))
+    data.setVar('_PARSE_TIME_EXPANSIONS', parse_expansions)
+    if 'bmap-tools' in parentfn:
+        bb.note('bmap-tools parse_expansions: %s/%s = %s' % (id(data), id(parse_expansions), parse_expansions))
 
     # "include" or "require" accept zero to n space-separated file names to include.
     for fn in fns.split():


-- 
Best Regards, Patrick Ohly

The content of this message is my personal opinion only and although
I am an employee of Intel, the statements I make here in no way
represent Intel's position on the issue, nor am I authorized to speak
on behalf of Intel on this matter.