Avoid repeatedly appending to yaml_implicit_resolvers

Repeated calls to `resolve` can experience performance degredation, if
`add_implicit_resolver` has been called with `first=None` (to add an
implicit resolver with an unspecified first character).

For example, every time `foo` is encountered, the "wildcard implicit
resolvers" (with `first=None`) will be appended to the list of implicit
resolvers for strings starting with `f`, which will normally be the
resolver for booleans. The list `yaml_implicit_resolvers['f']` will keep
getting longer. The same behavior applies for any first-letter matches
with existing implicit resolvers.

This change avoids unintentionally mutating the lists in the class-level
dict `yaml_implicit_resolvers` by looping through a temporary copy.

Fixes: #439
This commit is contained in:
Phil Sphicas 2020-09-18 00:29:02 -07:00 committed by Ingy döt Net
parent a001f27825
commit fc914d52c4
2 changed files with 4 additions and 4 deletions

View File

@ -146,8 +146,8 @@ class BaseResolver(object):
resolvers = self.yaml_implicit_resolvers.get(u'', [])
else:
resolvers = self.yaml_implicit_resolvers.get(value[0], [])
resolvers += self.yaml_implicit_resolvers.get(None, [])
for tag, regexp in resolvers:
wildcard_resolvers = self.yaml_implicit_resolvers.get(None, [])
for tag, regexp in resolvers + wildcard_resolvers:
if regexp.match(value):
return tag
implicit = implicit[1]

View File

@ -146,8 +146,8 @@ class BaseResolver:
resolvers = self.yaml_implicit_resolvers.get('', [])
else:
resolvers = self.yaml_implicit_resolvers.get(value[0], [])
resolvers += self.yaml_implicit_resolvers.get(None, [])
for tag, regexp in resolvers:
wildcard_resolvers = self.yaml_implicit_resolvers.get(None, [])
for tag, regexp in resolvers + wildcard_resolvers:
if regexp.match(value):
return tag
implicit = implicit[1]