…ce file path (#44587)

Using `absoluteFromSourceFile` leverages the cache of the resolved
absolute path, instead of having to compute it each time.

PR Close #44587

…4587)

This commit fixes an issue with symlink handling in `MockFileSystem`,
where entries within a symlink would fail to resolve.

PR Close #44587

…44587)

The `NgtscCompilerHost` is implemented using the `FileSystem`
abstraction of the compiler, which is implemented for tests using an
in-memory `MockFileSystem`. If the in-memory filesystem contains
symlinks, then using `NgtscCompilerHost` would not reflect their
resolved real path. Instead, the TypeScript compiler would use its
default implementation based on the real filesystem, which is unaware of
the in-memory `MockFileSystem` setup.

This change does not currently address any issues, but is being fixed
as it prevented a reproduction scenario from behaving correctly.

PR Close #44587

…44587)

When building a library, the `rootDir` option is configured to ensure
that all source files are present within the entry-point that is being
build. This imposes an extra constraint on the reference emit logic,
which does not allow emitting a reference into a source file outside of
this `rootDir`.

During the generation of type-check blocks we used to make a best-effort
estimation of whether a type reference can be emitted into the
type-check file. This check was relaxed in #42492 to support emitting
more syntax forms and type references, but this change did not consider
the `rootDir` constraint that is present in library builds. As such, the
compiler might conclude that a type reference is eligible for emit into
the type-check file, whereas in practice this would cause a failure.

This commit changes the best-effort estimation into a "preflight"
reference emit that is fully accurate as to whether emitting a type
reference is possible.

Fixes #43624

PR Close #44587

In certain scenarios, the compiler may have crashed with an
`Unable to write a reference` error which would be particularly hard
to diagnose. One of the primary reasons for this failure is when the
`rootDir` option is configured---typically the case for libraries---
and a source file is imported using a relative import from an external
entry-point. This would normally report TS6059 for the invalid relative
import, but the crash prevents this error from being surfaced.

This commit refactors the reference emit logic to result in an explicit
`Failure` state with a reason as to why the failure occurred. This state
is then used to report a `FatalDiagnosticException`, preventing a hard
crash.

Closes #44414

PR Close #44587

…ce file path (#44587)

Using `absoluteFromSourceFile` leverages the cache of the resolved
absolute path, instead of having to compute it each time.

PR Close #44587

…4587)

This commit fixes an issue with symlink handling in `MockFileSystem`,
where entries within a symlink would fail to resolve.

PR Close #44587

…44587)

The `NgtscCompilerHost` is implemented using the `FileSystem`
abstraction of the compiler, which is implemented for tests using an
in-memory `MockFileSystem`. If the in-memory filesystem contains
symlinks, then using `NgtscCompilerHost` would not reflect their
resolved real path. Instead, the TypeScript compiler would use its
default implementation based on the real filesystem, which is unaware of
the in-memory `MockFileSystem` setup.

This change does not currently address any issues, but is being fixed
as it prevented a reproduction scenario from behaving correctly.

PR Close #44587

…44587)

When building a library, the `rootDir` option is configured to ensure
that all source files are present within the entry-point that is being
build. This imposes an extra constraint on the reference emit logic,
which does not allow emitting a reference into a source file outside of
this `rootDir`.

During the generation of type-check blocks we used to make a best-effort
estimation of whether a type reference can be emitted into the
type-check file. This check was relaxed in #42492 to support emitting
more syntax forms and type references, but this change did not consider
the `rootDir` constraint that is present in library builds. As such, the
compiler might conclude that a type reference is eligible for emit into
the type-check file, whereas in practice this would cause a failure.

This commit changes the best-effort estimation into a "preflight"
reference emit that is fully accurate as to whether emitting a type
reference is possible.

Fixes #43624

PR Close #44587