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hcldec: Handle or forbid cty.DynamicPseudoType attributes in nested blocks

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Our BlockList, BlockSet, and BlockMap specs all produce cty collection
values, which require all elements to have a homogeneous type. If the
nested spec contained an attribute of type cty.DynamicPseudoType, that
would create the risk of each element having a different type, which would
previously have caused decoding to panic.

Now we either handle this during decode (BlockList, BlockSet) or forbid
it outright (BlockMap) to prevent that crash. BlockMap could _potentially_
also handle this during decode, but that would require a more significant
reorganization of its implementation than I want to take on right now,
and decoding dynamically-typed values inside collections is an edge case
anyway.
This commit is contained in:
Martin Atkins 2018-08-22 11:52:40 -07:00
parent d6049c2a04
commit b82170e941
3 changed files with 174 additions and 0 deletions
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9
cmd/hcldec/spec.go
View File

@ -394,6 +394,15 @@ func decodeBlockMapSpec(body hcl.Body, impliedName string) (hcldec.Spec, hcl.Dia
return errSpec, diags
}
if hcldec.ImpliedType(spec).HasDynamicTypes() {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid block_map spec",
Detail: "A block_map spec may not contain attributes with type 'any'.",
Subject: body.MissingItemRange().Ptr(),
})
}
return spec, diags
}

86
hcldec/public_test.go
View File

@ -426,6 +426,49 @@ b {}
},
{
`
b {
a = true
}
b {
a = 1
}
`,
&BlockListSpec{
TypeName: "b",
Nested: &AttrSpec{
Name: "a",
Type: cty.DynamicPseudoType,
},
},
nil,
cty.DynamicVal,
1, // Unconsistent argument types in b blocks
},
{
`
b {
a = true
}
b {
a = "not a bool"
}
`,
&BlockListSpec{
TypeName: "b",
Nested: &AttrSpec{
Name: "a",
Type: cty.DynamicPseudoType,
},
},
nil,
cty.ListVal([]cty.Value{
cty.StringVal("true"), // type unification generalizes all the values to strings
cty.StringVal("not a bool"),
}),
0,
},
{
`
b {}
b {}
`,
@ -465,6 +508,49 @@ b "bar" "baz" {}
},
{
`
b {
a = true
}
b {
a = 1
}
`,
&BlockSetSpec{
TypeName: "b",
Nested: &AttrSpec{
Name: "a",
Type: cty.DynamicPseudoType,
},
},
nil,
cty.DynamicVal,
1, // Unconsistent argument types in b blocks
},
{
`
b {
a = true
}
b {
a = "not a bool"
}
`,
&BlockSetSpec{
TypeName: "b",
Nested: &AttrSpec{
Name: "a",
Type: cty.DynamicPseudoType,
},
},
nil,
cty.SetVal([]cty.Value{
cty.StringVal("true"), // type unification generalizes all the values to strings
cty.StringVal("not a bool"),
}),
0,
},
{
`
b "foo" {}
b "bar" {}
`,

79
hcldec/spec.go
View File

@ -478,6 +478,44 @@ func (s *BlockListSpec) decode(content *hcl.BodyContent, blockLabels []blockLabe
if len(elems) == 0 {
ret = cty.ListValEmpty(s.Nested.impliedType())
} else {
// Since our target is a list, all of the decoded elements must have the
// same type or cty.ListVal will panic below. Different types can arise
// if there is an attribute spec of type cty.DynamicPseudoType in the
// nested spec; all given values must be convertable to a single type
// in order for the result to be considered valid.
etys := make([]cty.Type, len(elems))
for i, v := range elems {
etys[i] = v.Type()
}
ety, convs := convert.UnifyUnsafe(etys)
if ety == cty.NilType {
// FIXME: This is a pretty terrible error message.
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: fmt.Sprintf("Unconsistent argument types in %s blocks", s.TypeName),
Detail: "Corresponding attributes in all blocks of this type must be the same.",
Subject: &sourceRanges[0],
})
return cty.DynamicVal, diags
}
for i, v := range elems {
if convs[i] != nil {
newV, err := convs[i](v)
if err != nil {
// FIXME: This is a pretty terrible error message.
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: fmt.Sprintf("Unconsistent argument types in %s blocks", s.TypeName),
Detail: fmt.Sprintf("Block with index %d has inconsistent argument types: %s.", i, err),
Subject: &sourceRanges[i],
})
// Bail early here so we won't panic below in cty.ListVal
return cty.DynamicVal, diags
}
elems[i] = newV
}
}
ret = cty.ListVal(elems)
}
@ -593,6 +631,44 @@ func (s *BlockSetSpec) decode(content *hcl.BodyContent, blockLabels []blockLabel
if len(elems) == 0 {
ret = cty.SetValEmpty(s.Nested.impliedType())
} else {
// Since our target is a set, all of the decoded elements must have the
// same type or cty.SetVal will panic below. Different types can arise
// if there is an attribute spec of type cty.DynamicPseudoType in the
// nested spec; all given values must be convertable to a single type
// in order for the result to be considered valid.
etys := make([]cty.Type, len(elems))
for i, v := range elems {
etys[i] = v.Type()
}
ety, convs := convert.UnifyUnsafe(etys)
if ety == cty.NilType {
// FIXME: This is a pretty terrible error message.
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: fmt.Sprintf("Unconsistent argument types in %s blocks", s.TypeName),
Detail: "Corresponding attributes in all blocks of this type must be the same.",
Subject: &sourceRanges[0],
})
return cty.DynamicVal, diags
}
for i, v := range elems {
if convs[i] != nil {
newV, err := convs[i](v)
if err != nil {
// FIXME: This is a pretty terrible error message.
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: fmt.Sprintf("Unconsistent argument types in %s blocks", s.TypeName),
Detail: fmt.Sprintf("Block with index %d has inconsistent argument types: %s.", i, err),
Subject: &sourceRanges[i],
})
// Bail early here so we won't panic below in cty.ListVal
return cty.DynamicVal, diags
}
elems[i] = newV
}
}
ret = cty.SetVal(elems)
}
@ -675,6 +751,9 @@ func (s *BlockMapSpec) decode(content *hcl.BodyContent, blockLabels []blockLabel
if s.Nested == nil {
panic("BlockSetSpec with no Nested Spec")
}
if ImpliedType(s).HasDynamicTypes() {
panic("cty.DynamicPseudoType attributes may not be used inside a BlockMapSpec")
}
elems := map[string]interface{}{}
for _, childBlock := range content.Blocks {