inconsistent behavior of filter pulling from context based on name

[sqlalchemy-bot]

Migrated issue, originally created by Michael Bayer (@zzzeek)

this is related to #3 but seems different

from mako.template import Template

x = Template("""
X:
    ${"asdf" | h.foo}
""")

y = Template("""
Y:
    ${"asdf" | z.foo}
""")

z = Template("""
Z:
    ${h}
    ${"asdf" | h.foo}
""")

class h(object):
    foo = str

try:
    print x.render(h=h)
except NameError, e:
    print e

print y.render(z=h)
print z.render(h=h)

[sqlalchemy-bot]

Michael Bayer (@zzzeek) wrote:

the issue is because we consider the identifier 'h' to be declared at parse tree time. the undeclared_identifiers method of Expression and DefTag would need to be modified to walk through the parsed filter expression fully, and only pop out single, undotted identifiers that are present in DEFAULT_ESCAPES instead of everything in DEFAULT_ESCAPES - however, that still wouldn't solve this:

${'foo' | h, h.strip}

I suppose the fix to that would be, because h.strip is there, its undeclared. "h" as a builtin would basically be blown away from that.

the other solution is, don't allow "h.strip" in there. if we work with the regexp in codegen create_filter_callable(), we could have that. It's probably preferable.

[sqlalchemy-bot]

Changes by Michael Bayer (@zzzeek):

• set milestone to "0.4"

[sqlalchemy-bot]

Changes by Michael Bayer (@zzzeek):

• removed milestone (was: "0.4")

[sqlalchemy-bot]

Changes by Michael Bayer (@zzzeek):

• added labels: easy

[sqla-tester]

cocolato has proposed a fix for this issue in the main branch:

Support passing custom filters with the same name as built-in flags https://gerrit.sqlalchemy.org/c/sqlalchemy/mako/+/5557

[zzzeek]

1.3.7 is yanked. a test + yank is added in https://gerrit.sqlalchemy.org/c/sqlalchemy/mako/+/5579

[zzzeek]

add new tests that use 'n' as a default filter argument and ensure 'n' takes effect when used in this way

[cocolato]

add new tests that use 'n' as a default filter argument and ensure 'n' takes effect when used in this way添加使用“n”作为默认过滤器参数的新测试，并确保“n”以这种方式使用时生效

I will try this again.