Panic using null with coalescelist inside validation condition #26988

nyurik · 2020-11-20T00:26:13Z

Validation condition with a call to coalescelist(null, []) caused a panic during the plan stage (even before acquiring a lock). Ideally validation conditions should be lazy-evaluated (see #24998), so not to require this workaround.

Terraform Version

Terraform v0.13.5
+ provider registry.terraform.io/hashicorp/google v3.48.0
+ provider registry.terraform.io/hashicorp/kubernetes v1.13.3

Terraform Configuration Files

variable "node_pool_zones" {
  type        = list(string)
  default     = null

  validation {
    condition     = length(coalescelist(var.node_pool_zones, [])) == length(toset(coalescelist(var.node_pool_zones, [])))
    error_message = "Duplicates zones found."
  }
}

Crash Output

crash log here, not trivial to get a full one from the docker run env. Click to expand.

Error: Error in function call

  on ../../../../../modules/gcp/kubernetes/variables.tf line 7, in variable "node_pool_zones":
   7:     condition     = length(coalescelist(var.node_pool_zones, [])) == length(toset(coalescelist(var.node_pool_zones, [])))
    |----------------
    | var.node_pool_zones is null

Call to function "coalescelist" failed: panic in function implementation:
value is null
goroutine 47 [running]:
runtime/debug.Stack(0xc000a424d0, 0x221a960, 0x2c45fe0)
	/usr/local/go/src/runtime/debug/stack.go:24 +0x9d
github.com/zclconf/go-cty/cty/function.errorForPanic(...)
	/home/circleci/project/project/vendor/github.com/zclconf/go-cty/cty/function/error.go:44
github.com/zclconf/go-cty/cty/function.Function.Call.func1(0xc000a42950,
0xc000a42970)
	/home/circleci/project/project/vendor/github.com/zclconf/go-cty/cty/function/function.go:287
+0x8e
panic(0x221a960, 0x2c45fe0)
	/usr/local/go/src/runtime/panic.go:969 +0x166
github.com/zclconf/go-cty/cty.Value.LengthInt(0x2cef320, 0xc00024fda0, 0x0,
0x0, 0x1)
	/home/circleci/project/project/vendor/github.com/zclconf/go-cty/cty/value_ops.go:997
+0x269
github.com/zclconf/go-cty/cty/function/stdlib.glob..func15(0xc00050cb00, 0x2,
0x2, 0x2cef2e0, 0x411ecb0, 0x411ecb0, 0x0, 0x0, 0x40c686, 0xc000caa450, ...)
	/home/circleci/project/project/vendor/github.com/zclconf/go-cty/cty/function/stdlib/collection.go:243
+0xc3
github.com/zclconf/go-cty/cty/function.Function.Call(0xc000099980,
0xc00050cb00, 0x2, 0x2, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0)
	/home/circleci/project/project/vendor/github.com/zclconf/go-cty/cty/function/function.go:291
+0x4f2
github.com/hashicorp/hcl/v2/hclsyntax.(*FunctionCallExpr).Value(0xc0004d64b0,
0xc000737220, 0x0, 0xc000737240, 0xc00020c0c0, 0x1, 0x1, 0x1, 0x40bb300)
	/home/circleci/project/project/vendor/github.com/hashicorp/hcl/v2/hclsyntax/expression.go:412
+0x109d
github.com/hashicorp/hcl/v2/hclsyntax.(*FunctionCallExpr).Value(0xc0004d65a0,
0xc000737220, 0x2, 0x2, 0xc000096460, 0x2, 0x2, 0x2, 0x23052e0)
	/home/circleci/project/project/vendor/github.com/hashicorp/hcl/v2/hclsyntax/expression.go:378
+0x2610
github.com/hashicorp/hcl/v2/hclsyntax.(*BinaryOpExpr).Value(0xc0001e1810,
0xc000737220, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0)
	/home/circleci/project/project/vendor/github.com/hashicorp/hcl/v2/hclsyntax/expression_ops.go:144
+0x14d
github.com/hashicorp/terraform/terraform.(*evalVariableValidations).Eval(0xc0007383c0,
0x2d31320, 0xc0016c80d0, 0x1, 0x1, 0x0, 0x0)
	/home/circleci/project/project/terraform/eval_variable.go:165 +0x3d4
github.com/hashicorp/terraform/terraform.EvalRaw(0x2c87720, 0xc0007383c0,
0x2d31320, 0xc0016c80d0, 0x0, 0x0, 0x0, 0x0)
	/home/circleci/project/project/terraform/eval.go:49 +0xc7
github.com/hashicorp/terraform/terraform.(*EvalSequence).Eval(0xc000728660,
0x2d31320, 0xc0016c80d0, 0x1, 0x1, 0x4, 0xc000738430)
	/home/circleci/project/project/terraform/eval_sequence.go:20 +0xfd
github.com/hashicorp/terraform/terraform.EvalRaw(0x2c87120, 0xc000728660,
0x2d31320, 0xc0016c80d0, 0x22ba9a0, 0x3fae445, 0x221a960, 0xc000735520)
	/home/circleci/project/project/terraform/eval.go:49 +0xc7
github.com/hashicorp/terraform/terraform.Eval(0x2c87120, 0xc000728660,
0x2d31320, 0xc0016c80d0, 0xc000728660, 0x2c87120, 0xc000728660, 0x0)
	/home/circleci/project/project/terraform/eval.go:35 +0x4d
github.com/hashicorp/terraform/terraform.(*Graph).walk.func1(0x24402a0,
0xc0004b06c0, 0x0, 0x0, 0x0)
	/home/circleci/project/project/terraform/graph.go:73 +0xc77
github.com/hashicorp/terraform/dag.(*Walker).walkVertex(0xc0005805a0,
0x24402a0, 0xc0004b06c0, 0xc00020b880)
	/home/circleci/project/project/dag/walk.go:387 +0x357
created by github.com/hashicorp/terraform/dag.(*Walker).Update
	/home/circleci/project/project/dag/walk.go:309 +0x11d7
.


Error: Error in function call

  on ../../../../../modules/gcp/kubernetes/variables.tf line 7, in variable "node_pool_zones":
   7:     condition     = length(coalescelist(var.node_pool_zones, [])) == length(toset(coalescelist(var.node_pool_zones, [])))
    |----------------
    | var.node_pool_zones is null

Call to function "coalescelist" failed: panic in function implementation:
value is null
goroutine 47 [running]:
runtime/debug.Stack(0xc000a40fa8, 0x221a960, 0x2c45fe0)
	/usr/local/go/src/runtime/debug/stack.go:24 +0x9d
github.com/zclconf/go-cty/cty/function.errorForPanic(...)
	/home/circleci/project/project/vendor/github.com/zclconf/go-cty/cty/function/error.go:44
github.com/zclconf/go-cty/cty/function.Function.Call.func1(0xc000a41428,
0xc000a41448)
	/home/circleci/project/project/vendor/github.com/zclconf/go-cty/cty/function/function.go:287
+0x8e
panic(0x221a960, 0x2c45fe0)
	/usr/local/go/src/runtime/panic.go:969 +0x166
github.com/zclconf/go-cty/cty.Value.LengthInt(0x2cef320, 0xc00024fda0, 0x0,
0x0, 0x1)
	/home/circleci/project/project/vendor/github.com/zclconf/go-cty/cty/value_ops.go:997
+0x269
github.com/zclconf/go-cty/cty/function/stdlib.glob..func15(0xc00050cbc0, 0x2,
0x2, 0x2cef2e0, 0x411ecb0, 0x411ecb0, 0x0, 0x0, 0x40c686, 0xc000caa660, ...)
	/home/circleci/project/project/vendor/github.com/zclconf/go-cty/cty/function/stdlib/collection.go:243
+0xc3
github.com/zclconf/go-cty/cty/function.Function.Call(0xc000099980,
0xc00050cbc0, 0x2, 0x2, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0)
	/home/circleci/project/project/vendor/github.com/zclconf/go-cty/cty/function/function.go:291
+0x4f2
github.com/hashicorp/hcl/v2/hclsyntax.(*FunctionCallExpr).Value(0xc0004d6690,
0xc000737220, 0x0, 0xc000737300, 0xc001449f50, 0x1, 0x1, 0x1, 0x2c8b9e0)
	/home/circleci/project/project/vendor/github.com/hashicorp/hcl/v2/hclsyntax/expression.go:412
+0x109d
github.com/hashicorp/hcl/v2/hclsyntax.(*FunctionCallExpr).Value(0xc0004d6780,
0xc000737220, 0x0, 0xc0007372e0, 0xc00020c0c0, 0x1, 0x1, 0x1, 0x22d7d00)
	/home/circleci/project/project/vendor/github.com/hashicorp/hcl/v2/hclsyntax/expression.go:378
+0x2610
github.com/hashicorp/hcl/v2/hclsyntax.(*FunctionCallExpr).Value(0xc0004d6870,
0xc000737220, 0x2cef2e0, 0x411ecb0, 0x22d7d00, 0x411e860, 0xc00000e5c0, 0x1,
0x1)
	/home/circleci/project/project/vendor/github.com/hashicorp/hcl/v2/hclsyntax/expression.go:378
+0x2610
github.com/hashicorp/hcl/v2/hclsyntax.(*BinaryOpExpr).Value(0xc0001e1810,
0xc000737220, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0)
	/home/circleci/project/project/vendor/github.com/hashicorp/hcl/v2/hclsyntax/expression_ops.go:145
+0x1cc
github.com/hashicorp/terraform/terraform.(*evalVariableValidations).Eval(0xc0007383c0,
0x2d31320, 0xc0016c80d0, 0x1, 0x1, 0x0, 0x0)
	/home/circleci/project/project/terraform/eval_variable.go:165 +0x3d4
github.com/hashicorp/terraform/terraform.EvalRaw(0x2c87720, 0xc0007383c0,
0x2d31320, 0xc0016c80d0, 0x0, 0x0, 0x0, 0x0)
	/home/circleci/project/project/terraform/eval.go:49 +0xc7
github.com/hashicorp/terraform/terraform.(*EvalSequence).Eval(0xc000728660,
0x2d31320, 0xc0016c80d0, 0x1, 0x1, 0x4, 0xc000738430)
	/home/circleci/project/project/terraform/eval_sequence.go:20 +0xfd
github.com/hashicorp/terraform/terraform.EvalRaw(0x2c87120, 0xc000728660,
0x2d31320, 0xc0016c80d0, 0x22ba9a0, 0x3fae445, 0x221a960, 0xc000735520)
	/home/circleci/project/project/terraform/eval.go:49 +0xc7
github.com/hashicorp/terraform/terraform.Eval(0x2c87120, 0xc000728660,
0x2d31320, 0xc0016c80d0, 0xc000728660, 0x2c87120, 0xc000728660, 0x0)
	/home/circleci/project/project/terraform/eval.go:35 +0x4d
github.com/hashicorp/terraform/terraform.(*Graph).walk.func1(0x24402a0,
0xc0004b06c0, 0x0, 0x0, 0x0)
	/home/circleci/project/project/terraform/graph.go:73 +0xc77
github.com/hashicorp/terraform/dag.(*Walker).walkVertex(0xc0005805a0,
0x24402a0, 0xc0004b06c0, 0xc00020b880)
	/home/circleci/project/project/dag/walk.go:387 +0x357
created by github.com/hashicorp/terraform/dag.(*Walker).Update
	/home/circleci/project/project/dag/walk.go:309 +0x11d7
.

Steps to Reproduce

terraform plan

References

Variable Validation should use lazy evaluation #24998 - above was my attempt to work around the limitation of not being able to use var == null || ...

The text was updated successfully, but these errors were encountered:

danieldreier · 2020-11-23T17:46:22Z

Thank you for reporting this! I have reproduced this on 0.13.4 and 0.14-RC1

danieldreier · 2020-12-10T16:50:40Z

I have confirmed that this still happens in 0.14.2

alisdair · 2020-12-10T20:07:27Z

Thanks for reporting this bug. coalescelist should not be crashing here and we'll work on fixing that.

For your specific use case, you might find the try function helpful:

variable "node_pool_zones" {
  type        = list(string)
  default     = null

  validation {
    condition     = try(length(var.node_pool_zones), 0) == try(length(toset(var.node_pool_zones)), 0)
    error_message = "Duplicates zones found."
  }
}

As you've noticed, the binary logic operators (|| and &&) in Terraform do not short-circuit, and both sides will always be evaluated.

alisdair · 2020-12-10T20:58:56Z

There's a proposed fix for the panic in the upstream library here: zclconf/go-cty#81 If approved, this would be brought into Terraform in a future patch release.

alisdair · 2020-12-10T21:14:27Z

Note that, even with the above fix in place, your original configuration won't work as you'd hoped. coalescelist requires that at least one of its arguments is non-empty, so the result is an error (but not a panic):

Hopefully my earlier comment suggesting an alternative using try is helpful!

ghost · 2021-01-17T01:51:10Z

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you have found a problem that seems similar to this, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.

nyurik added bug new new issue not yet triaged labels Nov 20, 2020

danieldreier added config crash v0.13 Issues (primarily bugs) reported against v0.13 releases v0.14 Issues (primarily bugs) reported against v0.14 releases and removed new new issue not yet triaged labels Nov 23, 2020

danieldreier added the confirmed a Terraform Core team member has reproduced this issue label Dec 10, 2020

alisdair self-assigned this Dec 10, 2020

alisdair mentioned this issue Dec 10, 2020

Fix CoalesceList panic when passed null arguments zclconf/go-cty#81

Merged

alisdair mentioned this issue Dec 17, 2020

Update hcl and go-cty dependencies #27320

Merged

alisdair closed this as completed in #27320 Dec 17, 2020

ghost locked as resolved and limited conversation to collaborators Jan 17, 2021

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Panic using null with coalescelist inside validation condition #26988

Panic using null with coalescelist inside validation condition #26988

nyurik commented Nov 20, 2020 •

edited

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danieldreier commented Nov 23, 2020

danieldreier commented Dec 10, 2020

alisdair commented Dec 10, 2020

alisdair commented Dec 10, 2020

alisdair commented Dec 10, 2020

ghost commented Jan 17, 2021

Panic using null with coalescelist inside validation condition #26988

Panic using null with coalescelist inside validation condition #26988

Comments

nyurik commented Nov 20, 2020 • edited Loading

Terraform Version

Terraform Configuration Files

Crash Output

Steps to Reproduce

References

danieldreier commented Nov 23, 2020

danieldreier commented Dec 10, 2020

alisdair commented Dec 10, 2020

alisdair commented Dec 10, 2020

alisdair commented Dec 10, 2020

ghost commented Jan 17, 2021

nyurik commented Nov 20, 2020 •

edited

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