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The compiler performs cycle analysis for the used directives and pipes of a component's template to avoid introducing a cyclic import into the generated output. The used directives and pipes are represented by their output expression which would typically be an `ExternalExpr`; those are responsible for the generation of an `import` statement. Cycle analysis needs to determine the `ts.SourceFile` that would end up being imported by these `ExternalExpr`s, as the `ts.SourceFile` is then checked against the program's `ImportGraph` to determine if the import is allowed, i.e. does not introduce a cycle. To accomplish this, the `ExternalExpr` was dissected and ran through module resolution to obtain the imported `ts.SourceFile`. This module resolution step is relatively expensive, as it typically needs to hit the filesystem. Even in the presence of a module resolution cache would these module resolution requests generally see cache misses, as the generated import originates from a file for which the cache has not previously seen the imported module specifier. This commit removes the need for the module resolution by wrapping the generated `Expression` in an `EmittedReference` struct. This allows the reference emitter mechanism that is responsible for generating the `Expression` to also communicate from which `ts.SourceFile` the generated `Expression` would be imported, precluding the need for module resolution down the road. PR Close #40948 |
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| integrationtest | ||
| linker | ||
| ngcc | ||
| src | ||
| test | ||
| BUILD.bazel | ||
| index.ts | ||
| package.json | ||
| tsconfig-build.json | ||
| tsconfig.json | ||