Commit e865faf adds visual indentation for diagnostic messages using various
vertical line characters. The present commit disables this behaviour when
running with colourised output disabled.
While the contents of stderr are not intended to be part of the Terraform API,
this is currently how the hashicorp/terraform-exec library detects certain
error types in order to present them as well-known Go errors to the user. Such
detection is complicated when vertical lines are added to the CLI output at
unpredictable points.
I expect this change will also be helpful for screen reader users.
I frequently see people attempting to ask questions about Terraform's
error and warning messages but either only copying part of the message or
accidentally copying a surrounding paragraph that isn't part of the
message.
While I'm sure some of these are just "careless" mistakes, I've also
noticed that this has sometimes overlapped with someone asking a question
whose answer is written directly in the part of the message they didn't
include when copying, and so I have a theory that our current output
doesn't create a good enough visual hierarchy for sighted users to
understand where the diagnostic messages start and end when we show them
in close proximity to other content, or to other diagnostic messages.
As a result, some folks fail to notice the relevant message that might've
answered their question.
I tried a few different experiments for different approaches here, such
as adding more horizontal rules to the output and coloring the detail
text differently, but the approach that felt like the nicest compromise
to me was what's implemented here, which is to add a vertical line
along the left edge of each diagnostic message, colored to match with the
typical color we use for each diagnostic severity. This means that the
diagnostics end up slightly indented from what's around them, and the
vertical line seems to help subtly signal how we intended the content
to be grouped together.
In some terminal emulators, writing a character into the last column on a
row causes the terminal to immediately wrap to the beginning of the next
line, even if the very next character in the stream is a hard newline.
That can then lead to errant blank lines in the final output which make
it harder to navigate the visual hierarchy.
As a compromise to avoid this, we'll format our horizontal rules and
paragraphs to one column less than the terminal width. That does mean that
our horizontal rules won't _quite_ cover the whole terminal width, but
it seems like a good compromise in order to get consistent behavior across
a wider variety of terminal implementations.
We were previously using some ASCII art to create some visual divisions
between parts of the diagnostic output. Now that we are requiring a UTF-8
terminal we can print out box drawing characters instead.
Previously when printing the relevant variables involved in a failed
expression evaluation we would just skip over unknown values entirely.
There are some errors, though, which are _caused by_ a value being
unknown, in which case it's helpful to show which of the inputs to that
expression were known vs. unknown so that the user can limit their further
investigation only to the unknown ones.
While here I also added a special case for sensitive values that overrides
all other display, because we don't know what about a value is sensitive
and so better to give nothing away at the expense of a slightly less
helpful error message.
Diagnostic detail lines sometimes contain lines which include commands
suggested for the user to execute. By convention, these start with
leading whitespace to indicate that they are not prose.
This commit changes the diagnostic formatter to wrap each line of the
detail separately, and skips word wrapping for lines prefixed with
space. This prevents ugly and confusing wrapping of long command lines.
Diagnostics where the highlight range has an empty overlap with a line
would skip lines of the output. This is because if two ranges abut each
other, they can be considered to overlap, but that overlap is empty.
This results in an edge case in the diagnostic printer which causes the
line not to be printed.
Previously, if a diagnostic context spanned multiple lines, any lines
which did not overlap with the highlight range would be displayed as
blank. This commit fixes the bug.
The problem was caused by the unconditional use of `PartitionAround` to
split the line into before/highlighted/after ranges. When two ranges
don't overlap, this method returns empty ranges, which results in a
blank line. Instead, we first check if the ranges do overlap, and if not
we print the entire line from the context.
When warnings appear in isolation (not accompanied by an error) it's
reasonable to want to defer resolving them for a while because they are
not actually blocking immediate work.
However, our warning messages tend to be long by default in order to
include all of the necessary context to understand the implications of
the warning, and that can make them overwhelming when combined with other
output.
As a compromise, this adds a new CLI option -compact-warnings which is
supported for all the main operation commands and which uses a more
compact format to print out warnings as long as they aren't also
accompanied by errors.
The default remains unchanged except that the threshold for consolidating
warning messages is reduced to one so that we'll now only show one of
each distinct warning summary.
Full warning messages are always shown if there's at least one error
included in the diagnostic set too, because in that case the warning
message could contain additional context to help understand the error.
Previously we were using the experimental HCL 2 repository, but now we'll
shift over to the v2 import path within the main HCL repository as part of
actually releasing HCL 2.0 as stable.
This is a mechanical search/replace to the new import paths. It also
switches to the v2.0.0 release of HCL, which includes some new code that
Terraform didn't previously have but should not change any behavior that
matters for Terraform's purposes.
For the moment the experimental HCL2 repository is still an indirect
dependency via terraform-config-inspect, so it remains in our go.sum and
vendor directories for the moment. Because terraform-config-inspect uses
a much smaller subset of the HCL2 functionality, this does still manage
to prune the vendor directory a little. A subsequent release of
terraform-config-inspect should allow us to completely remove that old
repository in a future commit.
When HCL encounters an error during expression evaluation, it annotates
its diagnostics with information about the expression that was being
evaluated and the EvalContext it was evaluated in.
This gives us enough information to show helpful hints to the user about
the final values of any reference expressions that are present in the
expression, which is very useful extra context for expressions that get
evaluated multiple times, such as:
- Any expression in a block with "count" or "for_each" set
- The sub-expressions within a "for" expression
If we get a diagnostic message that references a source range, and if the
source code for the referenced file is available, we'll show a snippet of
the source code with the source range highlighted.
At the moment we have no cache of source code, so in practice this
codepath can never be visited. Callers to format.Diagnostic will be
gradually updated in subsequent commits.
This new method showDiagnostics takes any value that would be accepted by
tfdiags.Append and renders it to the UI.
This is intended to encourage consistent handling of the different kinds
of errors and diagnostics that can be produced, and allow richer error
objects like the HCL2 diagnostics to be easily unwrapped and shown in
their full-fidelity.
Alex Chan