Note that this is backed by a LRU cache (which we soon shall see more usage of), so if you're a heavy user of cached partials it may be evicted and
refreshed if needed. But in most cases every partial is only invoked once.
This commit also adds a timeout (the global `timeout` config option) to make infinite recursion in partials
easier to reason about.
```
name old time/op new time/op delta
IncludeCached-10 8.92ms ± 0% 8.48ms ± 1% -4.87% (p=0.016 n=4+5)
name old alloc/op new alloc/op delta
IncludeCached-10 6.65MB ± 0% 5.17MB ± 0% -22.32% (p=0.002 n=6+6)
name old allocs/op new allocs/op delta
IncludeCached-10 117k ± 0% 71k ± 0% -39.44% (p=0.002 n=6+6)
```
Closes#4086
Updates #9588
Under certain conditions, `howSimilarString` could reach a divide-by-
zero situation which causes bogus values to print in the cache potential
column of the template hints output. This situation essentially causes
a `int(math.NaN())` value to be returned and hilarity ensues thereafter.
We cannot (also, it doesn't add any value) use that when the `clock` is set,
* To measure time (before that global is set)
* To compare file timestamps re cache eviction
Fixes#9868
This commit adds support for return values in partials.
This means that you can now do this and similar:
{{ $v := add . 42 }}
{{ return $v }}
Partials without a `return` statement will be rendered as before.
This works for both `partial` and `partialCached`.
Fixes#5783
This commit adds a "cache potential" column when running `hugo --templateMetrics --templateMetricsHints`.
This is only calculated when `--templateMetricsHints` is set, as these calculations has an negative effect on the other timings.
This gives a value for partials only, and is a number between 0-100 that indicates if `partial` can be replaced with `partialCached`.
100 means that all execution of the same partial resulted in the same output.
You should do some manual research before going "all cache".
