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| author | Tristan Van Berkom <tristan.vanberkom@codethink.co.uk> | 2019-04-29 19:31:27 +0900 |
|---|---|---|
| committer | Tristan Van Berkom <tristan.vanberkom@codethink.co.uk> | 2019-04-29 19:34:18 +0900 |
| commit | 0312f051fe78d620a56371c7c07fce40c52a510e (patch) | |
| tree | 0b48176dad2aa7d0aa4d06c7d63042a9b39ea5e5 | |
| parent | 162c4166ce011f8dfca265549e6a343101a129aa (diff) | |
| download | buildstream-0312f051fe78d620a56371c7c07fce40c52a510e.tar.gz | |
plugin.py: Start plugin ID counter at ID 1
This was always intended, but was not well commented. The reason
we start plugin ID counters at 1 is that we prefer relying on
a falsy value to determine whether an ID holding variable has
been set or not.
This patch also adds a more informative assertion in Plugin._lookup()
This by itself essentially fixes #1012
| -rw-r--r-- | buildstream/plugin.py | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/buildstream/plugin.py b/buildstream/plugin.py index 2c94c212c..307aefa69 100644 --- a/buildstream/plugin.py +++ b/buildstream/plugin.py @@ -149,8 +149,12 @@ class Plugin(): # Unique id generator for Plugins # # Each plugin gets a unique id at creation. - # Ids are a monotically increasing integer - __id_generator = itertools.count() + # + # Ids are a monotically increasing integer which + # starts as 1 (a falsy plugin ID is considered unset + # in various parts of the codebase). + # + __id_generator = itertools.count(1) # Hold on to a lookup table by counter of all instantiated plugins. # We use this to send the id back from child processes so we can lookup @@ -656,6 +660,7 @@ class Plugin(): # @classmethod def _lookup(cls, unique_id): + assert unique_id != 0, "Looking up invalid plugin ID 0, ID counter starts at 1" assert unique_id in cls.__TABLE, "Could not find plugin with ID {}".format(unique_id) return cls.__TABLE[unique_id] |