Summary: I want to untangle `ResolutionRequest` once and for all, that starts by pulling stuff out :-)
Reviewed By: cpojer
Differential Revision: D5155316
fbshipit-source-id: a46ee9b40c6705edcac169adcfdffe25058ec810
Summary: This fixes a longstanding bug that happens when 2 bundles with the same entry path but different options (dev, minify, etc.) get mixed up in the reporting. To prevent that we just use a unique build ID for each bundle that the Server handles separately.
Reviewed By: cpojer
Differential Revision: D5147049
fbshipit-source-id: da5c9cfe8c6a5d888b5be737947800d213081d86
Summary: By getting rid of callbacks, we get a code that's pretty halved in size, and much easier to read, but we also fix bugs! When some of the code of Module would throw, we wouldn't catch it, meaning that packager would crash entirely. That's the case for when we have a Haste name mistach, for example. This changeste fixes that by instead capturing exceptions through the Promise chain, that bubble up all the way to the `Server` and reasonnably handled. People can then fix the Haste nane mismatch and refresh right away, and it'll work as expected.
Reviewed By: davidaurelio
Differential Revision: D5137408
fbshipit-source-id: b9e938b93e8d23738af49106bbae1fce97d7a5db
Summary: I'd like us to start having some decent testing at the packager/bundler level to check that there are no major breakage hapenning. This changeset introduce a simple test that just test the `buildBundle` public API. On the same model, I'd like to test the server API and behavior, and things such as hot module reloading. I hope this will also highlight the gross inconsistencies of the API, for example the Bundle/BundleBase hierarchy, that we can proceed to fix later.
Reviewed By: davidaurelio, cpojer
Differential Revision: D5121817
fbshipit-source-id: e0f3758c7fbb7a85cf51fb3cbc34c12d5374b7d3
Summary:
Code generation for indexed RAM bundles did not append module ID and dependencies. This fixes that.
Eventually, we only want to have the call to `addModuleIdsToModuleWrapper` in one place.
Reviewed By: jeanlauliac
Differential Revision: D5129255
fbshipit-source-id: 7f6148dd607bbf7c97e9df7936a07bde3f05b3aa
Summary: This allows us to get the new fix for recovery on duplicate modules.
Reviewed By: cpojer
Differential Revision: D5128975
fbshipit-source-id: 5a2b60430bbca1806a97798c482af8522366e071
Summary:
This changeset moves the creation of the transform cache at the top-level of the bundler so that:
* we can use alternative folders, such as the project path itself, that I think will be more robust especially for OSS;
* we can disable the cache completely, that is useful in some cases (for example, the script that fills the global cache).
The reasons I believe a local project path is more robust are:
* there are less likely conflicts between different users and different projects on a single machine;
* the cache is de facto cleaned up if you clone a fresh copy of a project, something I think is desirable;
* some people have been reporting that `tmpDir` just returns nothing;
* finally, it prevents another user from writing malicious transformed code in the cache into the shared temp dir—only people with write access to the project have write access to the cache, that is consistent.
Reviewed By: davidaurelio
Differential Revision: D5113121
fbshipit-source-id: 74392733a0be306a7119516d7905fc43cd8c778e
Summary:
* Internally, we already set up babel before calling into metro-bundler.
* Externally, I moved the setup calls to outside the packager/ folder.
If somebody has a custom integration with RN, they would need to setup babel themselves up until we make the open source split. By the time this is released in open source, an npm version of metro-bundler will be available for use.
Next step: also do this for the worker and remove setupBabel from the metro repo.
Reviewed By: davidaurelio
Differential Revision: D5121429
fbshipit-source-id: e77c6ccc23bef1d13fd74c4727be2d7e09d2d0ca
Summary: Adds support for “RAM bundle groups” (common section for module groups) to the new Buck integration
Reviewed By: jeanlauliac
Differential Revision: D5112065
fbshipit-source-id: 038c06b8f4133c7fcd39aba8bb04a5ef42594f3e
Summary: This is a first step towards doing an experiment I was talking about, that is, using the local directory (the directory where the config file lives) instead of the tmp dir, that is fragile.
Reviewed By: davidaurelio
Differential Revision: D5112326
fbshipit-source-id: 819636209972115e41213867f3eb78fbdf6ed9df
Summary: in order to prepare open sourcing React Native Packager, we have to move scripts specific to React Native to a directory that will continue to exist.
Reviewed By: javache
Differential Revision: D5112193
fbshipit-source-id: eac77d0d981aecef7ee52365a6856340420a5638
Summary:
Working on refactoring error handling in `_loadAsDir` I figured out it was oftentimes problematic to pass on the candidates out of the functions as an array, as in practice there's always a single "candidates" object passed out. Also, using an array prevented nice Flow typing and forced additional invariants to be added. So I replaced that by a return value that explicitely can be either a module, or resolution candidates. That way the semantic is more clear: we don't get any candidates if we did resolve properly, and at the same time we enforce returning candidates if we could not resolve any module.
At first I wanted to just have type `{module: TModule} | {candidate: TCandidate}`, but Flow would hit edge cases, so instead I added a field `type` that make it explicit what is the result of the resolution, and allows Flow to refine the type fully after we test that field. This allows us to remove the extraneous invariants. Also, a nice thing is that at a few places, even if the type of the candididate is different, Flow allows us to return the "resolved" object just as it is, that prevents using more memory and causing more garbage collection than necessary.
Since we're creating more objects with that solution, this will be slightly less performant than returning `Module` objects directly, but I don't think it is worth micro optimizing this at that point. If really we see this to be causing trouble later, I'd try to find solutions such as reusing a pool of objects. Ex. we could pass the result `Resolution` object as argument instead of returning a fresh one, but that would make the code less legible, more complex.
Reviewed By: davidaurelio
Differential Revision: D5111501
fbshipit-source-id: f41cdab00640124081cfdf07668169bb2d5c00be
Summary: We can switch that case easily since it was already discarding the error if any would happen.
Reviewed By: davidaurelio
Differential Revision: D5103851
fbshipit-source-id: a0991f626e94a45efbf666561041af258fdbef0a
Summary:
Make all properties of `ModuleTraansportLike` covariant to enforce read-only behavior at all sites using it.
The type only exists for compatibility reasons between old and new output functionality, and covariant properties give us stronger guarantees.
Reviewed By: jeanlauliac
Differential Revision: D5111667
fbshipit-source-id: 674658b07eb3a229cbc4344cb636e4a9ea4126d1
Summary:
Simplifies the `File` type by making `map` a non-optional, but nullable property.
Also adds helper functions for empty/virtual modules
Reviewed By: jeanlauliac
Differential Revision: D5111580
fbshipit-source-id: 9cab6634a9bdb0522dc36aec2abccaef9cf35339
Summary: Adds functionality to assemble an indexed source map to the new Buck integration. This implementation supports startup section optimisations. Hooking it up, and grouping optimisations will be in follow-ups.
Reviewed By: jeanlauliac
Differential Revision: D5106985
fbshipit-source-id: cc4c6ac8cfe4e718fc8bb2a8a93cb88914c92e0b
Summary: Because we don't want to test for `empty-module.ios.js`, etc. We know the module is supposed to be here. This simpler version makes it easier for me to switch the rest of the `loadAsFile` callsites to the "candidates" system to the "candidates" system.
Reviewed By: davidaurelio
Differential Revision: D5103816
fbshipit-source-id: 7e7d9be27573a1f33d562aeb850759e073fbc72f
Summary: For the Buck integration (work-in-progress), we want to add the ability to do some custom preprocessing similar to the packager server. The signature is different so I prefer to have a separate function for that. Also we don't need the transform options right now, I suggest we don't add them for now and add them later if necessary.
Reviewed By: davidaurelio
Differential Revision: D5094632
fbshipit-source-id: 1775ddef90b331deabc5be3e57a67436bce06c82
Summary:
'source' is not available in all shells on Linux (e.g. dash) and will silently fail launchPackager.command when called from runAndroid.js.
react-native run-android will thus silently fail to start the developement server ('JS server').
What existing problem does the pull request solve?
When running "react-native run-android" on the below reasonably vanilla Ubuntu system, the development server / packager script fails to start. It fails because sh defaults to dash (not bash) which doesn't know the command 'source'. dot (.) does the same as source, but works in all shells.
$ uname -a
Linux dallas 4.8.0-52-generic #55~16.04.1-Ubuntu SMP Fri Apr 28 14:36:29 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
$ which sh
/bin/sh
$ readlink -f /bin/sh
/bin/dash
react-native-cli: 2.0.1
react-native: 0.44.0
$ ps aux | grep packager
(nothing)
ps aux | grep packager
sh /home/xxx/code/react-native/AwesomeProject/node_modules/react-native/packager/launchPackager.command
node /home/xxx/code/react-native/AwesomeProject/node_modules/react-native/packager/../local-cli/cli.js start
Closes https://github.com/facebook/react-native/pull/14040
Differential Revision: D5096298
Pulled By: hramos
fbshipit-source-id: 88466e802c9bc4358840391edb37e153f0a6b1f7
Summary: Changes the `sourceMappingURL` comment from multi line to single line.
Reviewed By: johnislarry
Differential Revision: D5094791
fbshipit-source-id: f8fa2efd7f173290cac985564c06b4a118a80aae
Summary: separates modules of the dependency graph from the generated require calls to kick of the app. This is required to make RAM bundle generation work properly'
Reviewed By: jeanlauliac
Differential Revision: D5094635
fbshipit-source-id: fca69a3e2d9b030cdc4d4405c2b5e795b0d55f87
Summary: Releases the dependency map of modules after running the factory in release mode in order to save memory.
Reviewed By: cpojer
Differential Revision: D5086693
fbshipit-source-id: 68c57a2f98182ed1a732e1336e6d4fe5ce27abc3
Summary: RN configuration allows to specify a post-minify hook. This wasn’t called in the new Buck integration so far. Added here.
Reviewed By: cpojer
Differential Revision: D5087325
fbshipit-source-id: 74b58bd3a203716d8f01b5d7ba552b6ad1b575ce
Summary: Internally we use `multipart/form-data` to upload transformed files to the global cache, using the keys as file names. Unfortunately the server would read that and consider only the basename as the key, not the full path. So we wouldn't store the data under the right key. This is definitely a bug in the way upload is implemented: we should transmit the keys separately. But, this changeset offers a quick mitigation by avoiding slashes in the key, so that the whole key is a valid base file name.
Reviewed By: davidaurelio
Differential Revision: D5087780
fbshipit-source-id: 9e4a698c1f57c4c3b91b56b43eef82c1c7dd862b
Summary: Better to have *some* Flow coverage (I'd like 100% of packager covered from when we split it apart) than none.
Reviewed By: davidaurelio
Differential Revision: D5077757
fbshipit-source-id: b23169b3edf2bd3eb0e8a399d099151aa705b198
Summary:
It was hard to type the resolution main algo, I had to put type annotations explicitely everywhere, otherwise Flow would get in some kind of loop and do weird errors. I think it's because the algo is recursive and Flow tries to infer types too deeply because of the generics.
Anyway, apart from that it's good to get this extra type security in the few other places. We require Node v4 minimum, that according to the internets supports the `class` syntax without transform, and I verified that inheriting from `Map` actually works as expected.
Reviewed By: davidaurelio
Differential Revision: D5078023
fbshipit-source-id: 05dfc4acf5b07cdda8a7b36ec9cba216d1810643
Summary: Or, a case in point that Flow doesn't saves us from all the ills. I think it didn't complain because `MapWithDefaults` doesn't have proper typing. I'll deal with that separately.
Reviewed By: davidaurelio
Differential Revision: D5077707
fbshipit-source-id: c43623c5046d2dea9964685a44ad4877d060232e
Summary: I'd like to start typing the front-end so that it's easier to track adding new options, etc.
Reviewed By: davidaurelio
Differential Revision: D5069868
fbshipit-source-id: 9a18dca52efd486ca18f17d0ec434a5ec1c1649c
Summary: This makes it easier to verify correctness when adding new config/args.
Reviewed By: davidaurelio
Differential Revision: D5069537
fbshipit-source-id: 4d8058851900b23163d0f2744e91dd14dfcdd461
Summary:
The existing resolution logic of assets:
* goes over all the files of the asset's directory for every resolution request;
* duplicates the parsing logic of `AssetPaths` by building up a custom regex for each resolution request.
This changeset proposes to tweak this by building an index for each particular directory in which we're looking for assets, so that we don't have to crawl a single directory twice, and so that it reuses the logic of `AssetPaths.tryParse()` for determining variants.
Reviewed By: davidaurelio
Differential Revision: D5062435
fbshipit-source-id: 708fc5612f57b14565499fad741701269438c806
Summary:
We appended a `sourceMappingURL` in the same place where we write out the files. This will break output that is not a plain text file, like Random Access Bundles.
This moves the corresponding logic into the function that builds the bundle.
Reviewed By: cpojer
Differential Revision: D5061039
fbshipit-source-id: 17fadb5a687c8d4b1f29439e8bf946bae58eb2d9
Summary:
Not only is this function is building a custom Regex for every single file, but it's also duplicating some of the work of the inner function, that is already splitting up the platform/extension. This changeset refactors both function to have a more strict and legible logic to extract asset information. We extract the base name first, then we extract the resolution from it, instead of rematching platform and extension.
I stumbled on this while looking into refactoring the asset resolution logic of `ResolutionRequest#_loadAsAssetFile()`. The next step would be to reuse the exact same function for resolving assets instead of using a custom regex there as well.
Reviewed By: davidaurelio
Differential Revision: D5060589
fbshipit-source-id: b48d9a5d8e963be76cad5384c6bfb3e214a73587
Summary: Add Flow types, revealing a few problems, such as `isHaste` having the wrong return value in the "pseudo-mocks". But since the buck worker is in fact working, I guess these functions were never called... The point of typing this file is that I'm going to start aggressively pruning dead code in `node-haste` and hopefully, eventually, get rid of `Moduleish` and `Packageish`.
Reviewed By: davidaurelio
Differential Revision: D5052379
fbshipit-source-id: dab3f18f05fcf43fbbc48b589170b1cf367d6a48
Summary: This does not appear to be used anywhere anymore.
Reviewed By: cpojer
Differential Revision: D5052224
fbshipit-source-id: 142fdcdf48f4ad16a04bb747b41d623f214f7a68
Summary: Default arguments are dangerous, and it shows here again. `Server` was calling that function without passing down the platforms, meaning custom platform would not be accounted for, possibly causing all kinds of bugs for OSS use cases. Additional, the typing of `platform` across the stack was wrong: it can be `null`, in which case we resolve the files without extension. The reason Flow didn't detect that issue before is because we use `Object.assign` to re-export the function from `DependencyGraph`, but Flow is not smart enough to propagate the types in that particular case. I'll remove all the other re-export, as it may uncover further type errors.
Reviewed By: davidaurelio
Differential Revision: D5052070
fbshipit-source-id: 7b427ec036ca74b5dcd7c88f7dfa0df541b8eb6b
Summary: in new-style builds, the prelude is not wrapped into an IIFE, so `global` is not available. Since the bundle as a whole is not running in strict mode, we can access the global object with `this`.
Reviewed By: jeanlauliac
Differential Revision: D5051731
fbshipit-source-id: 4003b5e57ba8626e38e68e92d5778c2c59ca69a5
Summary:
A quick fix to ensure RNTest works. This PR changes the process root for where packager is run, resulting in the right `cwd` directory path when RN launches RNTester.
Closes https://github.com/facebook/react-native/pull/13947
Differential Revision: D5052093
Pulled By: davidaurelio
fbshipit-source-id: 506a8cd63f1709c948bcc4586467020d380ba85e
Summary: I stumbled on this while refactoring that function, and i realised that, I believe it doesn't make sense to take into account the platform extension of the "potiential" file path. The reason is, if you try to require "foo.ios.png", the returned asset name would be "foo", and thus we'd try to find "foo.${ext}.png" where `ext` could actually be `android` or anything else! So it's confusing. There's no reason we should allow callsites to specify platform anyway I think. With this changeset we're not losing any functionality, but it might require people to fix some incorrect callsites.
Reviewed By: cpojer
Differential Revision: D5051791
fbshipit-source-id: 2a1ec7a8bfa6791b6016213305a72bc0b81f23b9
Summary: I found myself a few times wanting that transform, that makes it slightly simpler to have bound method. So I propose we add it. Not a big deal though. Note it also allows static properties with the same syntax, that is handy.
Reviewed By: davidaurelio
Differential Revision: D5051579
fbshipit-source-id: 7ebf7c709bf52a30a525550c1eda1a6a2f7b8e1e
Summary:
Pass `localPath` to transformers to allow usage of plugins like `transform-react-jsx-source` that don’t conflict with x-machine caches, e.g. Buck or our own global cache.
These caches don’t work properly if paths local to a specific machine are part of cached outputs.
Reviewed By: jeanlauliac
Differential Revision: D5044147
fbshipit-source-id: 1177afb48d6dd9351738fcd4da8f9f6357e25e81
Summary:
Changes the global cache to use *local paths* rather than base names of files for the cache key. This is to enable correct usage of babel transforms like `transform-react-jsx-source` that use file paths in their output.
It remains a responsibility of the transform implementer to pass relative paths to babel if the global cache is being used.
Reviewed By: jeanlauliac
Differential Revision: D5044028
fbshipit-source-id: 2ef1e1545e510a18ab49a307053d91b4f40269b2
Summary: `transformModulePath` used to be an optional string, because `ConfigT` allowed for an optional `getTransformModulePath` method. Effectively, we required it to be present. This builds on top of the cleanups around `ConfigT` and gets rid of the flow error suppressions
Reviewed By: jeanlauliac
Differential Revision: D5037466
fbshipit-source-id: bc5c9cbc566e7aa74e7f6397e69fa87cdac7bc00
Summary: That's a bit of an experimental changeset, I wanted to experiment how we can track with more precision the resolution and this is what I come with. That allows us to know what has been tested if we canot find a match. It also uses a simpler control flow with early `return`s all across. Finally, this reflect the strategy I want to apply for the rest of the resolution. (Right now the error is still not great, as it may be deeply nested, as in the case of packages resolution.)
Reviewed By: davidaurelio
Differential Revision: D5044040
fbshipit-source-id: 2e256174506f80d90ee83175057666d530785788
Summary: Internally when adding `format` we have a lint rule that automatically reformat using `prettier` and the project rule. I'm concerned how we can ensure this stays consistent when merging PRs though. It's not a big issue because the volume of PRs is low, but we'll have to figure it out later on.
Reviewed By: davidaurelio
Differential Revision: D5035830
fbshipit-source-id: 6f2bc9eb8212938ff785a34d2684efd1a9813e1a
Summary: That module is not used anymore, remove it and its dependency `joi`.
Reviewed By: cpojer
Differential Revision: D5028909
fbshipit-source-id: 90b9b156fbfe642cce93a530faf8ce91c5b848f5
Summary: Adds flow type defs for uglify, and fixes the two issues found
Reviewed By: jeanlauliac
Differential Revision: D5029190
fbshipit-source-id: eb5947b051844938da241e002b727edc1384e3a6
Summary: This removes the single-use "garbage collection" class and make a single `TransformCache` instead. The reason for doing this is that I'd like to experiment with using a local dir based on the root path instead of the `tmpdir()` folder, because on some platform using the temp dir is subject to permissions problem, sometimes it is empty, and on all platform it is vulnerable to concurrency issues.
Reviewed By: davidaurelio
Differential Revision: D5027591
fbshipit-source-id: e1176e0e88111116256f7b2b173a0b36837a887d
Summary: I'm continuing my changes to avoid `lstat`-ing the folders when we don't really need to. That changeset in particular proposes to remove the check in `_loadAsDir`. The rationale is that right after that we try for the presence of the `package.json`. If that file exists, the folder necessarily exist so we can switch these two `if` blocks for sure without changing the logic. Finally, at the end we look for the "index" file. By removing the folder check, packager would now report "file `foo/index` does not exist" rather than "directory `foo` does not exist" if the folder does not exist. I think it's not much worse, especially as both of these are unhelpful for what I believe to be a large number of cases already anyway. Indeed, the whole algo is based on a series of try/catch, and only the very last try will see its error surfaced. But, most often, it'd be useful for earlier tries to be surfaced to the user. I do want to improve that; meanwhile, however, I sense it's not a big deal to remove that folder check for all these reasons. If you don't agree, I do have another proposition: we could catch errors generated by the last `_loadAsFile` call, and rethrow them as directory errors instead (if `dirExists` return `true`). That way, the call to `dirExists` would only happen in case of errors (but that could still happen quite a lot as a result).
Reviewed By: davidaurelio
Differential Revision: D5028341
fbshipit-source-id: 2d4c99c0f352b71599482aa529728559466b76fd
Summary: I think we don't really need to check the directory beforehand, the function to find asset will just return an empty array. As for the error message, I tried adding a require of an asset file somewhere, but due to the way the ResolutionRequest algo work, it generates a final error message that unrealted ("Directory ... does not exist", instead of the "asset does not exist"). I plan to revamp the way errors are handled such as the error message clearly identifies what file paths have been inspected.
Reviewed By: davidaurelio
Differential Revision: D5028118
fbshipit-source-id: 496472001c0a3d4192bfef4a0c8a0dc8a9a0fa82
Summary: This is not used by live code anymore.
Reviewed By: cpojer
Differential Revision: D5029114
fbshipit-source-id: 9ab9f6075407623debfe23bc121cc48ae8903917
Summary: I've been confused for a long time by this, and I think it's better late than never. I propose we rename that file to make it more explicit where that class lives, and so that it's consistent with the test file, name `DependencyGraph-test.js`
Reviewed By: davidaurelio
Differential Revision: D5020556
fbshipit-source-id: d54a501c3995f3fea16a5bfc6ca72993f73c4873
Summary: Moves custom transform options into their own property when returning custom properties. This helps both transitioning to a `select` function as well as implementing RAM bundle support for the new buck integration
Reviewed By: jeanlauliac
Differential Revision: D5028075
fbshipit-source-id: 25fe3072023cc063deef537a12012d4bb3173579
Summary: Afaik. the list of asset types is hardcoded for the Buck worker so far, and I'm not sure how that would be customizable. For now, let's include all the default asset extensions.
Reviewed By: davidaurelio
Differential Revision: D5002607
fbshipit-source-id: 41069e817d2b73156bca684bc2f73077132928a7
Summary:
There was an error with packager symbolization on Windows because it looks like `allowHalfOpen: true` doesn't work properly when using named sockets. This uses a random port on localhost for the connection instead on Windows as a workaround.
**Test plan**
Tested that symbolization works on both mac and windows by triggering a warning in UIExplorer.
Closes https://github.com/facebook/react-native/pull/13828
Differential Revision: D5019537
Pulled By: davidaurelio
fbshipit-source-id: 62c5b5f270e553a7d413bb4d1bab2406380f1d4f
Summary:
- [x] Explain the **motivation** for making this change.
- [x] Provide a **test plan** demonstrating that the code is solid.
- [x] Match the **code formatting** of the rest of the codebase.
- [x] Target the `master` branch, NOT a "stable" branch.
I have a need to bundle a pre-optimized external lib with my RN application. Until RN 0.42 I had been using a .babelignore to prevent the packager from trying to optimize this file and choke.
It seems in 0.42 and higher I'm no longer allowed to ignore the file.
This issue has also been reported as #12071
Details on the reasoning for this patch can be found in the issue I originally filed: https://github.com/facebook/react-native/issues/13168
What existing problem does the pull request solve?
This PR restores the functionality with babel ignoring files that existed in 0.41 before this patch:
0849f84df2 (diff-4676ea0b3c55c65c3929aa993144f07f)
Here's a screenshot of this patch properly ignoring the file I referenced in https://github.com/facebook/react-native/issues/13168 to be ignored.
![screen shot 2017-04-27 at 12 48 32 am](https://cloud.githubusercontent.com/assets/21967/25469653/524dbc0c-2ae3-11e7-81a6-faca2f4d21fe.png)
The patch relies on the `ignored` value of the call to `babel.transform` and if true returns the src in a object per instruction from loganfsmyth from BabelJS core team.
To test, add a file to the `ignore` array of a `.babelrc` file in a React Native project with this fork.
I was unable to locate a test file for the transformer.js
Fixes#12071, #13168
Closes https://github.com/facebook/react-native/pull/13681
Differential Revision: D5017565
Pulled By: davidaurelio
fbshipit-source-id: 421f57b5ce192eedd46fae4285d8a741cb5f8e71
Summary: Well that's silly but I noticed with faster terminal progress updates, packager *feels* a bit faster :D
Reviewed By: davidaurelio
Differential Revision: D5002528
fbshipit-source-id: 8a3d5e929dd7fb09ebafda3422886c631016a40f
Summary: Fixes building release builds with the new buck integration.
Reviewed By: jeanlauliac
Differential Revision: D5002441
fbshipit-source-id: e7716324c7c8dd0bfcaf5b39cf716ac589e948e8
Summary: Enforces a `'default'` property to be present on the transform variant mapping. This will allow us to simplify transforms of assets and json to only provide one variant for the new Buck build system.
Reviewed By: jeanlauliac
Differential Revision: D5002052
fbshipit-source-id: 2a7240c1b2450f62de686c46ab2c2e5a75dea399