Commit Graph

4 Commits

Author SHA1 Message Date
Martin Atkins c007e3a7da tfdiags: Helper to construct SourceRange from hcl.Range
HCL will be the most frequent origin of a source range, so this helper
should make it easier to translate these between the two worlds so we
can more easily use them in native Terraform diagnostics and other
messaging.
2017-10-16 17:51:16 -07:00
Martin Atkins 780e758f1e tfdiags: Allow construction of RPC-friendly Diagnostics
Due to the use of interfaces, Diagnostics is not super-friendly to the gob
encoding we currently use for plugin RPC. To mitigate this, we provide
a helper that converts all of the wrapped objects into a predictable flat
structure that we can pre-emptively register with gob.

This means that the decoded Diagnostics still has the same meaning as
the original, though the original wrapped errors (if any) are lost and
thus our errwrap integration won't be effective any longer.
2017-10-06 11:46:07 -07:00
Martin Atkins ab5efb805c tfdiags: SourceRange.StartString
This helper provides a concise string showing the filename, start line and
start column for a range, for easy inclusion in error messages.
2017-10-06 11:46:07 -07:00
Martin Atkins 61cd3bf02a tfdiags: new package for normalizing error and warning messages
Currently we lean heavily on the Go error type as our primary means of
describing errors, and along with that use several more specialized
implementations of it in different spots for additional capabilities such
as multiple errors in one object, source code range references, etc.

We also have a rather ad-hoc approach of returning an array of warnings
from certain functions along with one or multiple errors.

This rather-disorganized approach makes it hard for us to present
user-facing error messages consistently. As a step towards mitigating
this, package tfdiags provides a model for user-facing error and warning
messages and helper functions for creating them from various other
error and warning types used elsewhere in Terraform.

This mechanism is intended to be used to report errors and warnings where
the audience is the Terraform user, and so it may go a few layers deep
down the call stack into codepaths like config parsing, interpolation, etc
but is primarily a UX concern. The deepest reaches of Terraform core will
continue using "error" as normal, with higher layers preparing error
messages for presentation to the user.

To avoid needing to change the interface of every function that might
generate error diagnostics, the Diagnostics type can be "smuggled" via
an error value through other APIs and then unwrapped at the other end,
though it will lose any naked warnings (without at least one error) along
the way, and so codepaths that are expected to generate warnings
(validation, primarily) should use the concrete Diagnostics type
throughout the call chain.
2017-10-06 11:46:07 -07:00