Previously, if a trait's analysis step resulted in diagnostics, the trait would be considered "errored" and no further operations, including register, would be performed. Effectively, this meant that the compiler would pretend the class in question was actually undecorated. However, this behavior is problematic for several reasons: 1. It leads to inaccurate diagnostics being reported downstream. For example, if a component is put into the error state, for example due to a template error, the NgModule which declares the component would produce a diagnostic claiming that the declaration is neither a directive nor a pipe. This happened because the compiler wouldn't register() the component trait, so the component would not be recorded as actually being a directive. 2. It can cause incorrect behavior on incremental builds. This bug is more complex, but the general issue is that if the compiler fails to associate a component and its module, then incremental builds will not correctly re-analyze the module when the component's template changes. Failing to register the component as such is one link in the larger chain of issues that result in these kinds of issues. 3. It lumps together diagnostics produced during analysis and resolve steps. This is not causing issues currently as the dependency graph ensures the right classes are re-analyzed when needed, instead of showing stale diagnostics. However, the dependency graph was not intended to serve this role, and could potentially be optimized in ways that would break this functionality. This commit removes the concept of an "errored" trait entirely from the trait system. Instead, analyzed and resolved traits have corresponding (and separate) diagnostics, in addition to potentially `null` analysis results. Analysis (but not resolution) diagnostics are carried forward during incremental build operations. Compilation (emit) is only performed when a trait reaches the resolved state with no diagnostics. This change is functionally different than before as the `register` step is now performed even in the presence of analysis errors, as long as analysis results are also produced. This fixes problem 1 above, and is part of the larger solution to problem 2. PR Close #39923
Angular Compatibility Compiler (ngcc)
This compiler will convert node_modules
compiled with ngc
, into node_modules
which
appear to have been compiled with ngtsc
.
This conversion will allow such "legacy" packages to be used by the Ivy rendering engine.
Building
The project is built using Bazel:
yarn bazel build //packages/compiler-cli/ngcc
Unit Testing
The unit tests are built and run using Bazel:
yarn bazel test //packages/compiler-cli/ngcc/test
Integration Testing
There are tests that check the behavior of the overall executable:
yarn bazel test //packages/compiler-cli/ngcc/test:integration