terraform/config/lang/check_identifier.go

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package lang
import (
"fmt"
"sync"
"github.com/hashicorp/terraform/config/lang/ast"
)
// IdentifierCheck is a SemanticCheck that checks that all identifiers
// resolve properly and that the right number of arguments are passed
// to functions.
type IdentifierCheck struct {
Scope *Scope
err error
lock sync.Mutex
}
func (c *IdentifierCheck) Visit(root ast.Node) error {
c.lock.Lock()
defer c.lock.Unlock()
defer c.reset()
root.Accept(c.visit)
return c.err
}
func (c *IdentifierCheck) visit(raw ast.Node) ast.Node {
if c.err != nil {
return raw
}
switch n := raw.(type) {
case *ast.Call:
c.visitCall(n)
case *ast.VariableAccess:
c.visitVariableAccess(n)
case *ast.Concat:
// Ignore
case *ast.LiteralNode:
// Ignore
default:
c.createErr(n, fmt.Sprintf("unknown node: %#v", raw))
}
// We never do replacement with this visitor
return raw
}
func (c *IdentifierCheck) visitCall(n *ast.Call) {
// Look up the function in the map
function, ok := c.Scope.LookupFunc(n.Func)
if !ok {
c.createErr(n, fmt.Sprintf("unknown function called: %s", n.Func))
return
}
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// Break up the args into what is variadic and what is required
args := n.Args
if function.Variadic && len(args) > len(function.ArgTypes) {
args = n.Args[:len(function.ArgTypes)]
}
// Verify the number of arguments
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if len(args) != len(function.ArgTypes) {
c.createErr(n, fmt.Sprintf(
"%s: expected %d arguments, got %d",
n.Func, len(function.ArgTypes), len(n.Args)))
return
}
}
func (c *IdentifierCheck) visitVariableAccess(n *ast.VariableAccess) {
// Look up the variable in the map
if _, ok := c.Scope.LookupVar(n.Name); !ok {
c.createErr(n, fmt.Sprintf(
"unknown variable accessed: %s", n.Name))
return
}
}
func (c *IdentifierCheck) createErr(n ast.Node, str string) {
c.err = fmt.Errorf("%s: %s", n.Pos(), str)
}
func (c *IdentifierCheck) reset() {
c.err = nil
}