terraform/configs/configschema/validate_traversal.go

174 lines
5.7 KiB
Go

package configschema
import (
"fmt"
"sort"
"github.com/hashicorp/hcl/v2"
"github.com/hashicorp/hcl/v2/hclsyntax"
"github.com/zclconf/go-cty/cty"
"github.com/hashicorp/terraform/internal/didyoumean"
"github.com/hashicorp/terraform/internal/tfdiags"
)
// StaticValidateTraversal checks whether the given traversal (which must be
// relative) refers to a construct in the receiving schema, returning error
// diagnostics if any problems are found.
//
// This method is "optimistic" in that it will not return errors for possible
// problems that cannot be detected statically. It is possible that an
// traversal which passed static validation will still fail when evaluated.
func (b *Block) StaticValidateTraversal(traversal hcl.Traversal) tfdiags.Diagnostics {
if !traversal.IsRelative() {
panic("StaticValidateTraversal on absolute traversal")
}
if len(traversal) == 0 {
return nil
}
var diags tfdiags.Diagnostics
next := traversal[0]
after := traversal[1:]
var name string
switch step := next.(type) {
case hcl.TraverseAttr:
name = step.Name
case hcl.TraverseIndex:
// No other traversal step types are allowed directly at a block.
// If it looks like the user was trying to use index syntax to
// access an attribute then we'll produce a specialized message.
key := step.Key
if key.Type() == cty.String && key.IsKnown() && !key.IsNull() {
maybeName := key.AsString()
if hclsyntax.ValidIdentifier(maybeName) {
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: `Invalid index operation`,
Detail: fmt.Sprintf(`Only attribute access is allowed here. Did you mean to access attribute %q using the dot operator?`, maybeName),
Subject: &step.SrcRange,
})
return diags
}
}
// If it looks like some other kind of index then we'll use a generic error.
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: `Invalid index operation`,
Detail: `Only attribute access is allowed here, using the dot operator.`,
Subject: &step.SrcRange,
})
return diags
default:
// No other traversal types should appear in a normal valid traversal,
// but we'll handle this with a generic error anyway to be robust.
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: `Invalid operation`,
Detail: `Only attribute access is allowed here, using the dot operator.`,
Subject: next.SourceRange().Ptr(),
})
return diags
}
if attrS, exists := b.Attributes[name]; exists {
// For attribute validation we will just apply the rest of the
// traversal to an unknown value of the attribute type and pass
// through HCL's own errors, since we don't want to replicate all of
// HCL's type checking rules here.
val := cty.UnknownVal(attrS.Type)
_, hclDiags := after.TraverseRel(val)
diags = diags.Append(hclDiags)
return diags
}
if blockS, exists := b.BlockTypes[name]; exists {
moreDiags := blockS.staticValidateTraversal(name, after)
diags = diags.Append(moreDiags)
return diags
}
// If we get here then the name isn't valid at all. We'll collect up
// all of the names that _are_ valid to use as suggestions.
var suggestions []string
for name := range b.Attributes {
suggestions = append(suggestions, name)
}
for name := range b.BlockTypes {
suggestions = append(suggestions, name)
}
sort.Strings(suggestions)
suggestion := didyoumean.NameSuggestion(name, suggestions)
if suggestion != "" {
suggestion = fmt.Sprintf(" Did you mean %q?", suggestion)
}
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: `Unsupported attribute`,
Detail: fmt.Sprintf(`This object has no argument, nested block, or exported attribute named %q.%s`, name, suggestion),
Subject: next.SourceRange().Ptr(),
})
return diags
}
func (b *NestedBlock) staticValidateTraversal(typeName string, traversal hcl.Traversal) tfdiags.Diagnostics {
if b.Nesting == NestingSingle || b.Nesting == NestingGroup {
// Single blocks are easy: just pass right through.
return b.Block.StaticValidateTraversal(traversal)
}
if len(traversal) == 0 {
// It's always valid to access a nested block's attribute directly.
return nil
}
var diags tfdiags.Diagnostics
next := traversal[0]
after := traversal[1:]
switch b.Nesting {
case NestingSet:
// Can't traverse into a set at all, since it does not have any keys
// to index with.
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: `Cannot index a set value`,
Detail: fmt.Sprintf(`Block type %q is represented by a set of objects, and set elements do not have addressable keys. To find elements matching specific criteria, use a "for" expression with an "if" clause.`, typeName),
Subject: next.SourceRange().Ptr(),
})
return diags
case NestingList:
if _, ok := next.(hcl.TraverseIndex); ok {
moreDiags := b.Block.StaticValidateTraversal(after)
diags = diags.Append(moreDiags)
} else {
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: `Invalid operation`,
Detail: fmt.Sprintf(`Block type %q is represented by a list of objects, so it must be indexed using a numeric key, like .%s[0].`, typeName, typeName),
Subject: next.SourceRange().Ptr(),
})
}
return diags
case NestingMap:
// Both attribute and index steps are valid for maps, so we'll just
// pass through here and let normal evaluation catch an
// incorrectly-typed index key later, if present.
moreDiags := b.Block.StaticValidateTraversal(after)
diags = diags.Append(moreDiags)
return diags
default:
// Invalid nesting type is just ignored. It's checked by
// InternalValidate. (Note that we handled NestingSingle separately
// back at the start of this function.)
return nil
}
}