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Move alternatives into main design section for discussion

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Varun Saini 2024-09-11 16:21:19 -07:00
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docs/amended-alias-resolution.md
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@ -19,7 +19,7 @@ Otherwise, we will assume the given string does not contain an alias and will re
There have been disagreements about which approach is more appropriate, so this RFC will serve as a way to document the ongoing discussion and the final decision we make. There have been disagreements about which approach is more appropriate, so this RFC will serve as a way to document the ongoing discussion and the final decision we make.
## Design and Drawbacks ## Possible Designs and Drawbacks
Below, we have multiple different options for syntax and resolution semantics. Below, we have multiple different options for syntax and resolution semantics.
For each design, assume that the following `.luaurc` file is defined: For each design, assume that the following `.luaurc` file is defined:
@ -74,9 +74,26 @@ The main drawback of this approach is that projects with many _internal_ depende
This is similar to [darklua's approach](https://darklua.com/docs/path-require-mode/). This is similar to [darklua's approach](https://darklua.com/docs/path-require-mode/).
#### (1c) All explicit prefixes necessary
An alternative approach is to combine approaches (1a) and (1b) and always require prefixes for disambiguation.
In this scenario, any unprefixed path will _always_ result in an error.
```luau
-- Error: must have either "@", "./", or "../" prefix
require("libs/dependency")
-- Requires ./libs/dependency.luau
require("./libs/dependency")
-- Requires /My/Libraries/Directory/dependency.luau
require("@libs/dependency")
```
The main drawback of this approach is that it is not backwards compatible with any existing code that uses unprefixed require statements.
### (2) Strongly recommend explicit prefixes ### (2) Strongly recommend explicit prefixes
We don't make the `@`, `./`, or `../` prefixes necessary, but we strongly recommend them. We don't make the `@`, `./`, or `../` prefixes necessary like in approach (1c), but we strongly recommend them.
This can be accomplished by allowing unprefixed paths but throwing an error if they resolve to multiple files. This can be accomplished by allowing unprefixed paths but throwing an error if they resolve to multiple files.
There is a performance cost to this: currently, if we successfully match a given path to a file, we stop searching for other matches. There is a performance cost to this: currently, if we successfully match a given path to a file, we stop searching for other matches.
@ -99,31 +116,13 @@ require("@libs/dependency")
This is a compromise between approaches (1a) and (1b) that sacrifices performance for compatibility and readability. This is a compromise between approaches (1a) and (1b) that sacrifices performance for compatibility and readability.
## Alternatives ### (3) Use implicit resolution ordering to avoid `@` prefix
### All explicit prefixes necessary
An alternative approach is to combine approaches (1a) and (1b) and always require prefixes for disambiguation.
In other words, this is similar to approach (2), but any unprefixed path will _always_ result in an error.
This avoids the performance cost of approach (2), but it is not backwards compatible with existing code.
```luau
-- Error: must have either "@", "./", or "../" prefix
require("libs/dependency")
-- Requires ./libs/dependency.luau
require("./libs/dependency")
-- Requires /My/Libraries/Directory/dependency.luau
require("@libs/dependency")
```
### Use implicit resolution ordering to avoid `@` prefix
If we choose to remove the `@` prefix, we must define an implicit resolution ordering. If we choose to remove the `@` prefix, we must define an implicit resolution ordering.
In essence, aliases must either represent overrides or fallbacks for relative path resolution. In essence, aliases must either represent overrides or fallbacks for relative path resolution.
A drawback of this approach is that implicit resolution ordering can be confusing, and people disagree on which ordering is best. A drawback of this approach is that implicit resolution ordering can be confusing, and people disagree on which ordering is best.
#### Aliases as overrides #### (3a) Aliases as overrides
If aliases were overrides, we would have the following behavior. If aliases were overrides, we would have the following behavior.
This is identical to the [old RFC](https://github.com/luau-lang/luau/pull/969)'s behavior. This is identical to the [old RFC](https://github.com/luau-lang/luau/pull/969)'s behavior.
@ -138,7 +137,7 @@ require("./libs/dependency")
require("@libs/dependency") require("@libs/dependency")
``` ```
#### Aliases as fallbacks #### (3b) Aliases as fallbacks
If aliases were fallbacks, we would have the following behavior. If aliases were fallbacks, we would have the following behavior.
```luau ```luau