[Buildroot] [git commit] support/graph-depends: detect circular dependencies
Thomas Petazzoni
thomas.petazzoni at free-electrons.com
Sun Feb 7 22:20:38 UTC 2016
commit: https://git.buildroot.net/buildroot/commit/?id=f48c08f0f58cf99268a1f6be1edf96e5438a83b1
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/master
Currently, if there is a circular dependency in the packages, the
graph-depends script just errors out with a Python RuntimeError which is
not caught, resulting in a very-long backtrace which does not provide
any hint as what the real issue is (even if "RuntimeError: maximum
recursion depth exceeded" is a pretty good hint at it).
We fix that by recursing the dependency chain of each package, until we
either end up with a package with no dependency, or with a package
already seen along the current dependency chain.
We need to introduce a new function, check_circular_deps(), because we
can't re-use the existing ones:
- remove_mandatory_deps() does not iterate,
- remove_transitive_deps() does iterate, but we do not call it for the
top-level package if it is not 'all'
- it does not make sense to use those functions anyway, as they were
not designed to _check_ but to _act_ on the dependency chain.
Since we've had time-related issues in the past, we do not want to
introduce yet another time-hog, so here are timings with the circular
dependency check:
$ time python -m cProfile -s cumtime support/scripts/graph-depends
[...]
28352654 function calls (20323050 primitive calls) in 87.292 seconds
Ordered by: cumulative time
ncalls tottime percall cumtime percall filename:lineno(function)
1 0.012 0.012 87.292 87.292 graph-depends:24(<module>)
21 0.000 0.000 73.685 3.509 subprocess.py:473(_eintr_retry_call)
7 0.000 0.000 73.655 10.522 subprocess.py:768(communicate)
7 73.653 10.522 73.653 10.522 {method 'read' of 'file' objects}
5/1 0.027 0.005 43.488 43.488 graph-depends:164(get_all_depends)
5 0.003 0.001 43.458 8.692 graph-depends:135(get_depends)
1 0.001 0.001 25.712 25.712 graph-depends:98(get_version)
1 0.001 0.001 13.457 13.457 graph-depends:337(remove_extra_deps)
1717 1.672 0.001 13.050 0.008 graph-depends:290(remove_transitive_deps)
9784086/2672326 5.079 0.000 11.363 0.000 graph-depends:274(is_dep)
2883343/1980154 2.650 0.000 6.942 0.000 graph-depends:262(is_dep_uncached)
1 0.000 0.000 4.529 4.529 graph-depends:121(get_targets)
2883343 1.123 0.000 1.851 0.000 graph-depends:246(is_dep_cache_insert)
9784086 1.783 0.000 1.783 0.000 graph-depends:255(is_dep_cache_lookup)
2881580 0.728 0.000 0.728 0.000 {method 'update' of 'dict' objects}
1 0.001 0.001 0.405 0.405 graph-depends:311(check_circular_deps)
12264/1717 0.290 0.000 0.404 0.000 graph-depends:312(recurse)
[...]
real 1m27.371s
user 1m15.075s
sys 0m12.673s
The cumulative time spent in check_circular_deps is just below 0.5s,
which is largely less than 1% of the total run time.
Signed-off-by: "Yann E. MORIN" <yann.morin.1998 at free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
Cc: Samuel Martin <s.martin49 at gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
---
support/scripts/graph-depends | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/support/scripts/graph-depends b/support/scripts/graph-depends
index c0c6a94..d933eaa 100755
--- a/support/scripts/graph-depends
+++ b/support/scripts/graph-depends
@@ -313,6 +313,32 @@ def remove_transitive_deps(pkg,deps):
def remove_mandatory_deps(pkg,deps):
return [p for p in deps[pkg] if p not in ['toolchain', 'skeleton']]
+# This function will check that there is no loop in the dependency chain
+# As a side effect, it builds up the dependency cache.
+def check_circular_deps(deps):
+ def recurse(pkg):
+ if not pkg in list(deps.keys()):
+ return
+ if pkg in not_loop:
+ return
+ not_loop.append(pkg)
+ chain.append(pkg)
+ for p in deps[pkg]:
+ if p in chain:
+ sys.stderr.write("\nRecursion detected for : %s\n" % (p))
+ while True:
+ _p = chain.pop()
+ sys.stderr.write("which is a dependency of: %s\n" % (_p))
+ if p == _p:
+ sys.exit(1)
+ recurse(p)
+ chain.pop()
+
+ not_loop = []
+ chain = []
+ for pkg in list(deps.keys()):
+ recurse(pkg)
+
# This functions trims down the dependency list of all packages.
# It applies in sequence all the dependency-elimination methods.
def remove_extra_deps(deps):
@@ -324,6 +350,7 @@ def remove_extra_deps(deps):
deps[pkg] = remove_transitive_deps(pkg,deps)
return deps
+check_circular_deps(dict_deps)
dict_deps = remove_extra_deps(dict_deps)
dict_version = get_version([pkg for pkg in allpkgs
if pkg != "all" and not pkg.startswith("root")])
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