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Type:
Bug
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Status: Done
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Priority:
Blocker
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Resolution: Fixed
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Affects Version/s: 3.11.0b1
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Labels:
Mustache template rendering duplicates data with
Expected output:
# Mustache duplication issue test # Test1 Data = v1 Data = v2 # Test2 Data = v1 Data = v2 Other data = v3 Other data = v4
Produced output (note data duplication in Test2 series):
# Mustache duplication issue test # Test1 Data = v1 Data = v2 # Test2 Data = v1 Data = v2 Other data = v3 Other data = v4 Data = v1 Data = v2 Other data = v3 Other data = v4
This was discussed on #cfengine. Here is the chat log excerpt:
14:38| TedZ| OK, I'll look at just JSON then
14:43| TedZ| OK, I see it. When you iterate over a key-value container, you iterate over every key and value pair.
14:43| TedZ| so your template for test 2 sees two keys and iterates twice.
14:44| TedZ| simply change test2 to an array wrapping the key-value container: "test2": [{
14:44| TedZ| "data": [
14:44| TedZ| "v1",
14:44| TedZ| "v2"
14:44| TedZ| ],
14:44| TedZ| "otherdata": [
14:44| TedZ| "v3",
14:44| TedZ| "v4"
14:44| TedZ| ]
14:44| TedZ| }]
14:44| TedZ|
14:44| TedZ| sorry for the paste, I didn't mean to flood
14:45| * neilhwatson head hurts
14:45| cfbot| If you write your own CFEngine policy make it as reusable as possible.
14:46| dsx| ok, why that worked in 3.6?
14:46| TedZ| dsx is iterating over test2. test2 has two things in it. So the template iterates twice.
14:46| neilhwatson| What if the template had stated test2.data rather than data?
14:47| TedZ| dsx: not sure, my guess is that it was a bug in 3.6. I would check the official Mustache spec to be sure about this, but I think I'm right.
14:47| TedZ| neilhwatson: test2.data inside the test2 iteration would look for test2.test2.data
14:49| dsx| TedZ: as far as I know, mustache came from JS world, and in JS iterating over a map would essentially iterate over map keys
14:52| TedZ| right, so the behavior is correct and my workaround seems the best way forward.
14:59| dsx| TedZ: no, behavior is not correct. also, if you have time and curiosity, here is the official demo: http://mustache.github.io/#demo and here is template and
data to put in: http://hastebin.com/efawofifew.txt
15:06| TedZ| dsx: at this point I'd take your example and open a ticket. It seems like we have a disagreement on the official spec. From
https://mustache.github.io/mustache.5.html I am certain non-empty lists are rendered sequentially, but it's not clear if key-value containers are treated as
lists, and they don't have a specific iteration behavior. We're not going to resolve it here, but I think we've at least understood the problem.
Some policy for CFE-2125
bundle agent main
{
vars:
"data" data => '{
"object0": {
"object0-0": {
"object0-0-0": [
"v1",
"v2"
]
},
"object0-1": {
"object0-1-0": [
"v1",
"v2"
],
"object0-1-1": [
"v3",
"v4"
]
}
},
"object1": [ "object1-val1", "object1-val2" ],
"non-false": {
"color": "blue"
},
"false": false
}';
# Iterate over top object rendering keys with custom extension. -top- is
# also a custom extension
"iterate_object_keys" string => "# Iterate over custom -top- object rendering keys with custom extension `@`.
{{#-top-}}{{@}}
{{/-top-}}";
"at_also_iterate_array_vals" string => "# Iterate over array rendering keys (postion) with custom variable `@`.
{{#object1}}Iterate array key {{@}} = {{.}}
{{/object1}}";
"iterate_array_vals" string => "# Iterate over array rendering keys with standard variable `.`
{{#object1}}Data = {{.}}
{{/object1}}";
"iterate_deep_array_vals" string => "# Iterate over deep/nested array rendering keys with standard variable `.`
{{#object0.object0-0.object0-0-0}}object0.object0-0.object0-0-0 = {{.}}
{{/object0.object0-0.object0-0-0}}";
# Use non-false value as context for single rendering of block
"deep_object_no_sub_objects" string => "# Use a deep object reference to provide the context for the template
{{#object0.object0-1.object0-1-0}}object0-1-0 Key {{@}}, object0-1-0 Value {{.}}
{{/object0.object0-1.object0-1-0}}";
# Use non-false value as context for single rendering of block
"template" string => "# This should not print twice! Why should it NOT behave like deep_object_no_sub_objects above
{{#object0.object0-1}}
{{#object0-1-0}}object0-1-0 Key {{@}}, object0-1-0 Value {{.}}
{{/object0-1-0}}{{/object0.object0-1}}";
reports:
"CFEngine $(sys.cf_version)";
"# Data.$(const.n)$(with)"
with => string_mustache( '{{%-top-}}', @(data) );
"$(with)"
with => string_mustache( $(iterate_object_keys), @(data) );
"$(with)"
with => string_mustache( $(at_also_iterate_array_vals), @(data) );
"$(with)"
with => string_mustache( $(iterate_array_vals), @(data) );
"$(with)"
with => string_mustache( $(iterate_deep_array_vals), @(data) );
"$(with)"
with => string_mustache( $(deep_object_no_sub_objects), @(data) );
"$(with)"
with => string_mustache( $(template), @(data) );
}
R: CFEngine 3.11.0
R: # Data.
{
"false": false,
"non-false": {
"color": "blue"
},
"object0": {
"object0-0": {
"object0-0-0": [
"v1",
"v2"
]
},
"object0-1": {
"object0-1-0": [
"v1",
"v2"
],
"object0-1-1": [
"v3",
"v4"
]
}
},
"object1": [
"object1-val1",
"object1-val2"
]
}
R: # Iterate over custom -top- object rendering keys with custom extension `@`.
object0
object1
non-false
false
R: # Iterate over array rendering keys (postion) with custom variable `@`.
Iterate array key 0 = object1-val1
Iterate array key 1 = object1-val2
R: # Iterate over array rendering keys with standard variable `.`
Data = object1-val1
Data = object1-val2
R: # Iterate over deep/nested array rendering keys with standard variable `.`
object0.object0-0.object0-0-0 = v1
object0.object0-0.object0-0-0 = v2
R: # Use a deep object reference to provide the context for the template
object0-1-0 Key 0, object0-1-0 Value v1
object0-1-0 Key 1, object0-1-0 Value v2
R: # This should not print twice! Why should it NOT behave like deep_object_no_sub_objects above
object0-1-0 Key 0, object0-1-0 Value v1
object0-1-0 Key 1, object0-1-0 Value v2
object0-1-0 Key 0, object0-1-0 Value v1
object0-1-0 Key 1, object0-1-0 Value v2
- relates to
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- To Do
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