Add BuildDependsPolicy to check Build-Depends(-Arch) availability

Add a new "BuildDependsPolicy" that will check the satisfiability of
the build-dependencies listed in the Build-Depends and
Build-Depends-Arch fields.  This enables gating of packages based on
missing / broken build-dependencies.

There are some limitations:

 * Build-Depends-Indep is ignored for now.  Missing or broken packages
   listed in Build-Depends-Indep will be continue to be silently
   ignored.

 * Being a policy check, it does not enforce "self-containedness" as
   a package can still migrate before a build-dependency.  However,
   this can only happen if the build-dependency is ready to migrate
   itself.  If the build-dependency is not ready (e.g. new RC bugs),
   then packages build-depending on it cannot migrate either (unless
   the version in testing satisfies there requirements).

Signed-off-by: Niels Thykier <niels@thykier.net>

britney.py

@@ -198,7 +198,7 @@ from britney2.hints import HintParser
 from britney2.installability.builder import build_installability_tester
 from britney2.migrationitem import MigrationItem
 from britney2.policies import PolicyVerdict
-from britney2.policies.policy import AgePolicy, RCBugPolicy, PiupartsPolicy
+from britney2.policies.policy import AgePolicy, RCBugPolicy, PiupartsPolicy, BuildDependsPolicy
 from britney2.utils import (old_libraries_format, undo_changes,
                             compute_reverse_tree, possibly_compressed,
                             read_nuninst, write_nuninst, write_heidi,
@@ -511,6 +511,7 @@ class Britney(object):
         self.policies.append(AgePolicy(self.options, self.suite_info, MINDAYS))
         self.policies.append(RCBugPolicy(self.options, self.suite_info))
         self.policies.append(PiupartsPolicy(self.options, self.suite_info))
+        self.policies.append(BuildDependsPolicy(self.options, self.suite_info))
 
         for policy in self.policies:
             policy.register_hints(self._hint_parser)
@@ -568,6 +569,7 @@ class Britney(object):
                         [],
                         None,
                         True,
+                        None
                         )
 
             self.sources['testing'][pkg_name] = src_data
@@ -642,6 +644,7 @@ class Britney(object):
                         [],
                         None,
                         True,
+                        None,
                         )
             self.sources['testing'][pkg_name] = src_data
             self.sources['unstable'][pkg_name] = src_data
@@ -843,7 +846,7 @@ class Britney(object):
                     srcdist[source].binaries.append(pkg_id)
             # if the source package doesn't exist, create a fake one
             else:
-                srcdist[source] = SourcePackage(source_version, 'faux', [pkg_id], None, True)
+                srcdist[source] = SourcePackage(source_version, 'faux', [pkg_id], None, True, None)
 
             # add the resulting dictionary to the package list
             packages[pkg] = dpkg

britney2/__init__.py

@@ -9,14 +9,15 @@ SuiteInfo = namedtuple('SuiteInfo', [
 
 class SourcePackage(object):
 
-    __slots__ = ['version', 'section', 'binaries', 'maintainer', 'is_fakesrc']
+    __slots__ = ['version', 'section', 'binaries', 'maintainer', 'is_fakesrc', 'build_deps_arch']
 
-    def __init__(self, version, section, binaries, maintainer, is_fakesrc):
+    def __init__(self, version, section, binaries, maintainer, is_fakesrc, build_deps_arch):
         self.version = version
         self.section = section
         self.binaries = binaries
         self.maintainer = maintainer
         self.is_fakesrc = is_fakesrc
+        self.build_deps_arch = build_deps_arch
 
     def __getitem__(self, item):
         return getattr(self, self.__slots__[item])

britney2/excuse.py

@@ -75,7 +75,9 @@ class Excuse(object):
         self._policy_verdict = PolicyVerdict.REJECTED_PERMANENTLY
 
         self.invalid_deps = set()
+        self.invalid_build_deps = set()
         self.deps = {}
+        self.arch_build_deps = {}
         self.sane_deps = []
         self.break_deps = []
         self.newbugs = set()
@@ -135,10 +137,19 @@ class Excuse(object):
         if (name, arch) not in self.break_deps:
             self.break_deps.append( (name, arch) )
 
+    def add_arch_build_dep(self, name, arch):
+        if name not in self.arch_build_deps:
+            self.arch_build_deps[name] = []
+        self.arch_build_deps[name].append(arch)
+
     def invalidate_dep(self, name):
         """Invalidate dependency"""
         self.invalid_deps.add(name)
 
+    def invalidate_build_dep(self, name):
+        """Invalidate build-dependency"""
+        self.invalid_build_deps.add(name)
+
     def setdaysold(self, daysold, mindays):
         """Set the number of days from the upload and the minimum number of days for the update"""
         self.daysold = daysold
@@ -209,6 +220,17 @@ class Excuse(object):
         for (n,a) in self.break_deps:
             if n not in self.deps:
                 res += "<li>Ignoring %s depends: <a href=\"#%s\">%s</a>\n" % (a, n, n)
+        lastdep = ""
+        for x in sorted(self.arch_build_deps, key=lambda x: x.split('/')[0]):
+            dep = x.split('/')[0]
+            if dep == lastdep:
+                continue
+            lastdep = dep
+            if x in self.invalid_build_deps:
+                res = res + "<li>Build-Depends(-Arch): %s <a href=\"#%s\">%s</a> (not ready)\n" % (self.name, dep, dep)
+            else:
+                res = res + "<li>Build-Depends(-Arch): %s <a href=\"#%s\">%s</a>\n" % (self.name, dep, dep)
+
         if self.is_valid:
             res += "<li>Valid candidate\n"
         else:
@@ -258,13 +280,14 @@ class Excuse(object):
                 'on-architectures': sorted(self.missing_builds),
                 'on-unimportant-architectures': sorted(self.missing_builds_ood_arch),
             }
-        if self.deps or self.invalid_deps or self.break_deps:
+        if self.deps or self.invalid_deps or self.arch_build_deps or self.invalid_build_deps or self.break_deps:
             excusedata['dependencies'] = dep_data = {}
-            migrate_after = sorted(x for x in self.deps if x not in self.invalid_deps)
+            migrate_after = sorted((self.deps.keys() - self.invalid_deps)
+                                   | (self.arch_build_deps.keys() - self.invalid_build_deps))
             break_deps = [x for x, _ in self.break_deps if x not in self.deps]
 
-            if self.invalid_deps:
+            if self.invalid_deps or self.invalid_build_deps:
-                dep_data['blocked-by'] = sorted(self.invalid_deps)
+                dep_data['blocked-by'] = sorted(self.invalid_deps | self.invalid_build_deps)
             if migrate_after:
                 dep_data['migrate-after'] = migrate_after
             if break_deps:

britney2/policies/policy.py

@@ -8,6 +8,7 @@ import apt_pkg
 
 from britney2.hints import Hint, split_into_one_hint_per_package
 from britney2.policies import PolicyVerdict
+from britney2.utils import get_dependency_solvers
 
 
 class BasePolicy(object):
@@ -616,3 +617,80 @@ class PiupartsPolicy(BasePolicy):
             summary[source] = (state, url)
 
         return summary
+
+
+class BuildDependsPolicy(BasePolicy):
+
+    def __init__(self, options, suite_info):
+        super().__init__('build-depends', options, suite_info, {'unstable', 'tpu', 'pu'})
+        self._britney = None
+
+    def initialise(self, britney):
+        super().initialise(britney)
+        self._britney = britney
+
+    def apply_policy_impl(self, build_deps_info, suite, source_name, source_data_tdist, source_data_srcdist, excuse,
+                          get_dependency_solvers=get_dependency_solvers):
+        verdict = PolicyVerdict.PASS
+        britney = self._britney
+
+        # local copies for better performance
+        parse_src_depends = apt_pkg.parse_src_depends
+
+        # analyze the dependency fields (if present)
+        deps = source_data_srcdist.build_deps_arch
+        if not deps:
+            return verdict
+
+        sources_s = None
+        sources_t = None
+        unsat_bd = {}
+        relevant_archs = {binary.architecture for binary in source_data_srcdist.binaries
+                          if britney.all_binaries[binary].architecture != 'all'}
+
+        for arch in (arch for arch in self.options.architectures if arch in relevant_archs):
+            # retrieve the binary package from the specified suite and arch
+            binaries_s_a, provides_s_a = britney.binaries[suite][arch]
+            binaries_t_a, provides_t_a = britney.binaries['testing'][arch]
+            # for every dependency block (formed as conjunction of disjunction)
+            for block, block_txt in zip(parse_src_depends(deps, False, arch), deps.split(',')):
+                # if the block is satisfied in testing, then skip the block
+                if get_dependency_solvers(block, binaries_t_a, provides_t_a):
+                    # Satisfied in testing; all ok.
+                    continue
+
+                # check if the block can be satisfied in the source suite, and list the solving packages
+                packages = get_dependency_solvers(block, binaries_s_a, provides_s_a)
+                packages = [binaries_s_a[p].source for p in packages]
+
+                # if the dependency can be satisfied by the same source package, skip the block:
+                # obviously both binary packages will enter testing together
+                if source_name in packages:
+                    continue
+
+                # if no package can satisfy the dependency, add this information to the excuse
+                if not packages:
+                    excuse.addhtml("%s unsatisfiable Build-Depends(-Arch) on %s: %s" % (source_name, arch, block_txt.strip()))
+                    if arch not in unsat_bd:
+                        unsat_bd[arch] = []
+                    unsat_bd[arch].append(block_txt.strip())
+                    if verdict.value < PolicyVerdict.REJECTED_PERMANENTLY.value:
+                        verdict = PolicyVerdict.REJECTED_PERMANENTLY
+                    continue
+
+                if not sources_t:
+                    sources_t = britney.sources['testing']
+                    sources_s = britney.sources[suite]
+
+                # for the solving packages, update the excuse to add the dependencies
+                for p in packages:
+                    if arch not in self.options.break_arches:
+                        if p in sources_t and sources_t[p].version == sources_s[p].version:
+                            excuse.add_arch_build_dep("%s/%s" % (p, arch), arch)
+                        else:
+                            excuse.add_arch_build_dep(p, arch)
+        if unsat_bd:
+            build_deps_info['unsatisfiable-arch-build-depends'] = unsat_bd
+
+        return verdict
+

britney2/utils.py

@@ -721,11 +721,18 @@ def read_sources_file(filename, sources=None, intern=sys.intern):
         section = get_field('Section')
         if section:
             section = intern(section.strip())
+        build_deps_arch = ", ".join(x for x in (get_field('Build-Depends'), get_field('Build-Depends-Arch'))
+                                    if x is not None)
+        if build_deps_arch != '':
+            build_deps_arch = sys.intern(build_deps_arch)
+        else:
+            build_deps_arch = None
         sources[intern(pkg)] = SourcePackage(intern(ver),
                                              section,
                                              [],
                                              maint,
                                              False,
+                                             build_deps_arch,
                                              )
     return sources
 
@@ -789,14 +796,17 @@ def invalidate_excuses(excuses, valid, invalid):
 
     # build the reverse dependencies
     revdeps = defaultdict(list)
+    revbuilddeps = defaultdict(list)
     for exc in excuses.values():
         for d in exc.deps:
             revdeps[d].append(exc.name)
+        for d in exc.arch_build_deps:
+            revbuilddeps[d].append(exc.name)
 
     # loop on the invalid excuses
     for ename in iter_except(invalid.pop, KeyError):
         # if there is no reverse dependency, skip the item
-        if ename not in revdeps:
+        if ename not in revdeps and ename not in revbuilddeps:
             continue
         # if the dependency can be satisfied by a testing-proposed-updates excuse, skip the item
         if (ename + "_tpu") in valid:
@@ -807,11 +817,10 @@ def invalidate_excuses(excuses, valid, invalid):
             rdep_verdict = PolicyVerdict.REJECTED_BLOCKED_BY_ANOTHER_ITEM
 
         # loop on the reverse dependencies
+        if ename in revdeps:
             for x in revdeps[ename]:
-            if x in valid:
+                # if the item is valid and it is not marked as `forced', then we invalidate it
-                # if the item is valid and it is marked as `forced', skip the item
+                if x in valid and not excuses[x].forced:
-                if excuses[x].forced:
-                    continue
 
                     # otherwise, invalidate the dependency and mark as invalidated and
                     # remove the depending excuses
@@ -823,6 +832,20 @@ def invalidate_excuses(excuses, valid, invalid):
                     if excuses[x].policy_verdict.value < rdep_verdict.value:
                         excuses[x].policy_verdict = rdep_verdict
 
+        if ename in revbuilddeps:
+            for x in revbuilddeps[ename]:
+                # if the item is valid and it is not marked as `forced', then we invalidate it
+                if x in valid and not excuses[x].forced:
+
+                    # otherwise, invalidate the dependency and mark as invalidated and
+                    # remove the depending excuses
+                    excuses[x].invalidate_build_dep(ename)
+                    valid.discard(x)
+                    invalid.add(x)
+                    excuses[x].addhtml("Invalidated by build-dependency")
+                    if excuses[x].policy_verdict.value < rdep_verdict.value:
+                        excuses[x].policy_verdict = rdep_verdict
+
 
 def compile_nuninst(binaries_t, inst_tester, architectures, nobreakall_arches):
     """Compile a nuninst dict from the current testing

tests/test_policy.py

@@ -39,7 +39,7 @@ def create_excuse(name):
 def create_source_package(version, section='devel', binaries=None):
     if binaries is None:
         binaries = []
-    return SourcePackage(version, section, binaries, 'Random tester', False)
+    return SourcePackage(version, section, binaries, 'Random tester', False, None)
 
 
 def create_policy_objects(source_name, target_version, source_version):