packer crash

[hanwen-flow]

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Overview of the Issue

packer crash, after removing some sections from a working hcl file.

Reproduction Steps

unfortunately, I lost the repro while trying to reduce the input file.

Packer version

$ packer version
Packer v1.12.0

Simplified Packer Template

Operating system and Environment details

ubuntu 24.04

Log Fragments and crash.log files

$ cat crash.log~
2025/02/10 10:26:28 [INFO] Packer version: 1.12.0 [go1.22.9 linux amd64]
2025/02/10 10:26:28 [INFO] PACKER_CONFIG env var not set; checking the default config file path
2025/02/10 10:26:28 [INFO] PACKER_CONFIG env var set; attempting to open config file: /home/hanwen/.packerconfig
2025/02/10 10:26:28 [WARN] Config file doesn't exist: /home/hanwen/.packerconfig
2025/02/10 10:26:28 [INFO] Setting cache directory: /home/hanwen/.cache/packer
2025/02/10 10:26:28 [TRACE] listing potential installations for <nil> that match "". plugingetter.ListInstallationsOptions{PluginDirectory:"/home/hanwen/.config/packer/plugins", BinaryInstallationOptions:plugingetter.BinaryInstallationOptions{APIVersionMajor:"5", APIVersionMinor:"0", OS:"linux", ARCH:"amd64", Ext:"", Checksummers:[]plugingetter.Checksummer{plugingetter.Checksummer{Type:"sha256", Hash:(*sha256.digest)(0xc0004e4080)}}, ReleasesOnly:false}}
2025/02/10 10:26:28 [INFO] found external [chroot ebs ebssurrogate ebsvolume instance] builders from amazon plugin
2025/02/10 10:26:28 [INFO] found external [import] post-processors from amazon plugin
2025/02/10 10:26:28 found external [ami parameterstore secretsmanager] datasource from amazon plugin
2025/02/10 10:26:28 plugin "/home/hanwen/.config/packer/plugins/github.com/hashicorp/amazon/packer-plugin-amazon_v1.3.4_x5.0_linux_amd64" does not support Protobuf, forcing use of Gob
2025/02/10 10:26:28 [INFO] found external [-packer-default-plugin-name-] builders from docker plugin
2025/02/10 10:26:28 [INFO] found external [import push save tag] post-processors from docker plugin
2025/02/10 10:26:28 [TRACE] validateValue: not active for gcp_base_image_windows_2022_x86_64, so skipping
2025/02/10 10:26:28 [TRACE] validateValue: not active for prerelease, so skipping
2025/02/10 10:26:28 [TRACE] validateValue: not active for aws_base_image_debian12_arm64, so skipping
2025/02/10 10:26:28 [TRACE] validateValue: not active for aws_base_image_ubuntu2404_arm64, so skipping
2025/02/10 10:26:28 [TRACE] validateValue: not active for version, so skipping
2025/02/10 10:26:28 [TRACE] validateValue: not active for aws_customers, so skipping
2025/02/10 10:26:28 [TRACE] validateValue: not active for gcp_builder_project, so skipping
2025/02/10 10:26:28 [TRACE] validateValue: not active for aws_base_image_windows_2022_x86_64, so skipping
2025/02/10 10:26:28 [TRACE] validateValue: not active for gcp_builder_zone, so skipping
2025/02/10 10:26:28 [TRACE] validateValue: not active for gcp_builder_zone_arm, so skipping
2025/02/10 10:26:28 [TRACE] validateValue: not active for gcp_base_image_debian12_x86_64, so skipping
2025/02/10 10:26:28 [TRACE] validateValue: not active for gcp_base_image_debian12_arm64, so skipping
2025/02/10 10:26:28 [TRACE] validateValue: not active for script_debug, so skipping
2025/02/10 10:26:28 [TRACE] validateValue: not active for aws_base_image_ubuntu2004_arm64, so skipping
2025/02/10 10:26:28 [TRACE] validateValue: not active for aws_base_image_macos14_x86_64, so skipping
2025/02/10 10:26:28 [TRACE] validateValue: not active for aws_base_image_ubuntu2004_x86_64, so skipping
2025/02/10 10:26:28 [TRACE] validateValue: not active for gcp_base_image_debian11_x86_64, so skipping
2025/02/10 10:26:28 [TRACE] validateValue: not active for aws_base_image_debian11_arm64, so skipping
2025/02/10 10:26:28 [TRACE] validateValue: not active for aws_base_image_macos14_arm64, so skipping
2025/02/10 10:26:28 [TRACE] validateValue: not active for aws_builder_region, so skipping
2025/02/10 10:26:28 [TRACE] validateValue: not active for aws_base_image_debian12_x86_64, so skipping
2025/02/10 10:26:28 [TRACE] validateValue: not active for aws_macos_builder_region, so skipping
2025/02/10 10:26:28 [TRACE] validateValue: not active for aws_base_image_xxxxx_debian_11_x86_64, so skipping
2025/02/10 10:26:28 [TRACE] validateValue: not active for aws_base_image_debian11_x86_64, so skipping
2025/02/10 10:26:28 [TRACE] validateValue: not active for aws_base_image_ubuntu2404_x86_64, so skipping
2025/02/10 10:26:28 waiting for all plugin processes to complete...
panic: interface conversion: interface is nil, not dag.Vertex

goroutine 1 [running]:
github.com/hashicorp/packer/internal/dag.stronglyConnected(0xc0008f88e0, 0xc000527300, {0x1771840, 0xc0006dd9a0})
	github.com/hashicorp/packer/internal/dag/tarjan.go:31 +0x4fb
github.com/hashicorp/packer/internal/dag.StronglyConnected(0xc000527300)
	github.com/hashicorp/packer/internal/dag/tarjan.go:19 +0x267
github.com/hashicorp/packer/internal/dag.(*AcyclicGraph).Cycles(0x5041a6?)
	github.com/hashicorp/packer/internal/dag/dag.go:62 +0x19
github.com/hashicorp/packer/internal/dag.(*AcyclicGraph).Validate(0xc000527300)
	github.com/hashicorp/packer/internal/dag/dag.go:34 +0x2a
github.com/hashicorp/packer/hcl2template.(*PackerConfig).buildPrereqsDAG(0xc00058c000)
	github.com/hashicorp/packer/hcl2template/parser.go:446 +0x732
github.com/hashicorp/packer/hcl2template.(*PackerConfig).evaluateBuildPrereqs(0xc00058c000, 0x0)
	github.com/hashicorp/packer/hcl2template/parser.go:459 +0x69
github.com/hashicorp/packer/hcl2template.(*PackerConfig).Initialize(0xc00058c000, {0x60?, 0x2f?})
	github.com/hashicorp/packer/hcl2template/parser.go:524 +0x32e
github.com/hashicorp/packer/command.(*BuildCommand).RunContext(0xc0005dede0, {0x1fea400, 0xc000540140}, 0xc000736000)
	github.com/hashicorp/packer/command/build.go:105 +0xed
github.com/hashicorp/packer/command.(*BuildCommand).Run(0xc0005dede0, {0xc00003e0c0, 0x3, 0x3})
	github.com/hashicorp/packer/command/build.go:45 +0xbb
github.com/mitchellh/cli.(*CLI).Run(0xc00058cf00)
	github.com/mitchellh/cli@v1.1.5/cli.go:262 +0x5b8
main.wrappedMain()
	github.com/hashicorp/packer/main.go:274 +0xeac
main.realMain()
	github.com/hashicorp/packer/main.go:51 +0xd5
main.main()

[lbajolet-hashicorp]

Hey @hanwen-flow,

That's something you can probably work-around by using the --use-sequential-evaluation flag in your packer build command, which will force using the old-style template evaluation.
We replaced sequential/phased evaluation partially with a DAG in v1.12.0, so this bug you're seeing is likely an edge-case we mishandled and did not uncover during testing, apologies!

If you are able to reproduce the problem, it would be great for us to troubleshoot and eventually fix this one :)

[mscottford]

Apologies for the +1. I'm running into this problem as well, but I'm not sure exactly where the problem might be. I'm also running version 1.12.0 and I'm running on macOS 15.3.1 on an M3 Pro.

I can confirm that the --use-sequential-evaluation flag allows me to work around the problem.

[lbajolet-hashicorp]

Hey @mscottford,

There's been another issue opened on the same kind of problem as well, #13299, I'm considering closing this one as a duplicate, but I wonder if you're hitting the problem in a similar way, could you share a simplified template/logs for us to dig into?

[HenriBlacksmith]

I am facing the same bug when adding a local depending on a data block:

This fails:

data "http" "trusted_ca_certificates" {
  method = "GET"
  url    = "http://example.com/ca-bundle.crt"
}

locals {
  test = data.trusted_ca_certificates.url
}

This works without a crash:

data "http" "trusted_ca_certificates" {
  method = "GET"
  url    = "http://example.com/ca-bundle.crt"
}

packer inspect $(PACKER_VARIABLES) my-vmi

panic: interface conversion: interface is nil, not dag.Vertex

goroutine 1 [running]:
github.com/hashicorp/packer/internal/dag.stronglyConnected(0x1400091ee08, 0x140008146c0, {0x105acbb40, 0x140006795e0})
        github.com/hashicorp/packer/internal/dag/tarjan.go:31 +0x458
github.com/hashicorp/packer/internal/dag.StronglyConnected(0x140008146c0)
        github.com/hashicorp/packer/internal/dag/tarjan.go:19 +0x1f4
github.com/hashicorp/packer/internal/dag.(*AcyclicGraph).Cycles(0x1400091efe8?)
        github.com/hashicorp/packer/internal/dag/dag.go:62 +0x20
github.com/hashicorp/packer/internal/dag.(*AcyclicGraph).Validate(0x140008146c0)
        github.com/hashicorp/packer/internal/dag/dag.go:34 +0x28
github.com/hashicorp/packer/hcl2template.(*PackerConfig).buildPrereqsDAG(0x14000600140)
        github.com/hashicorp/packer/hcl2template/parser.go:446 +0x560
github.com/hashicorp/packer/hcl2template.(*PackerConfig).evaluateBuildPrereqs(0x14000600140, 0x1)
        github.com/hashicorp/packer/hcl2template/parser.go:459 +0x6c
github.com/hashicorp/packer/hcl2template.(*PackerConfig).Initialize(0x14000600140, {0x0?, 0x0?})
        github.com/hashicorp/packer/hcl2template/parser.go:524 +0x2c4
github.com/hashicorp/packer/command.(*ValidateCommand).RunContext(0x14000599380, {0x14000138020?, 0x3?}, 0x1400077e080)
        github.com/hashicorp/packer/command/validate.go:84 +0x124
github.com/hashicorp/packer/command.(*ValidateCommand).Run(0x14000599380, {0x14000138020, 0x3, 0x3})
        github.com/hashicorp/packer/command/validate.go:29 +0xac
github.com/mitchellh/cli.(*CLI).Run(0x14000523900)
        github.com/mitchellh/cli@v1.1.5/cli.go:262 +0x4a8
main.wrappedMain()
        github.com/hashicorp/packer/main.go:274 +0xc40
main.realMain()
        github.com/hashicorp/packer/main.go:51 +0xb8
main.main()
        github.com/hashicorp/packer/main.go:37 +0x1c



!!!!!!!!!!!!!!!!!!!!!!!!!!! PACKER CRASH !!!!!!!!!!!!!!!!!!!!!!!!!!!!

Packer crashed! This is always indicative of a bug within Packer.
A crash log has been placed at "crash.log" relative to your current
working directory. It would be immensely helpful if you could please
report the crash with Packer[1] so that we can fix this.

[1]: https://github.com/hashicorp/packer/issues

!!!!!!!!!!!!!!!!!!!!!!!!!!! PACKER CRASH !!!!!!!!!!!!!!!!!!!!!!!!!!!!
make: *** [packer-lint] Error 2

[HenriBlacksmith]

I am facing the same bug when adding a local depending on a data block:

This fails:

data "http" "trusted_ca_certificates" {
method = "GET"
url = "http://example.com/ca-bundle.crt"
}

locals {
test = data.trusted_ca_certificates.url
}
This works without a crash:

data "http" "trusted_ca_certificates" {
method = "GET"
url = "http://example.com/ca-bundle.crt"
}
packer inspect $(PACKER_VARIABLES) my-vmi
panic: interface conversion: interface is nil, not dag.Vertex

goroutine 1 [running]:
github.com/hashicorp/packer/internal/dag.stronglyConnected(0x1400091ee08, 0x140008146c0, {0x105acbb40, 0x140006795e0})
github.com/hashicorp/packer/internal/dag/tarjan.go:31 +0x458
github.com/hashicorp/packer/internal/dag.StronglyConnected(0x140008146c0)
github.com/hashicorp/packer/internal/dag/tarjan.go:19 +0x1f4
github.com/hashicorp/packer/internal/dag.(*AcyclicGraph).Cycles(0x1400091efe8?)
github.com/hashicorp/packer/internal/dag/dag.go:62 +0x20
github.com/hashicorp/packer/internal/dag.(*AcyclicGraph).Validate(0x140008146c0)
github.com/hashicorp/packer/internal/dag/dag.go:34 +0x28
github.com/hashicorp/packer/hcl2template.(*PackerConfig).buildPrereqsDAG(0x14000600140)
github.com/hashicorp/packer/hcl2template/parser.go:446 +0x560
github.com/hashicorp/packer/hcl2template.(*PackerConfig).evaluateBuildPrereqs(0x14000600140, 0x1)
github.com/hashicorp/packer/hcl2template/parser.go:459 +0x6c
github.com/hashicorp/packer/hcl2template.(*PackerConfig).Initialize(0x14000600140, {0x0?, 0x0?})
github.com/hashicorp/packer/hcl2template/parser.go:524 +0x2c4
github.com/hashicorp/packer/command.(*ValidateCommand).RunContext(0x14000599380, {0x14000138020?, 0x3?}, 0x1400077e080)
github.com/hashicorp/packer/command/validate.go:84 +0x124
github.com/hashicorp/packer/command.(*ValidateCommand).Run(0x14000599380, {0x14000138020, 0x3, 0x3})
github.com/hashicorp/packer/command/validate.go:29 +0xac
github.com/mitchellh/cli.(*CLI).Run(0x14000523900)
github.com/mitchellh/cli@v1.1.5/cli.go:262 +0x4a8
main.wrappedMain()
github.com/hashicorp/packer/main.go:274 +0xc40
main.realMain()
github.com/hashicorp/packer/main.go:51 +0xb8
main.main()
github.com/hashicorp/packer/main.go:37 +0x1c

!!!!!!!!!!!!!!!!!!!!!!!!!!! PACKER CRASH !!!!!!!!!!!!!!!!!!!!!!!!!!!!

Packer crashed! This is always indicative of a bug within Packer.
A crash log has been placed at "crash.log" relative to your current
working directory. It would be immensely helpful if you could please
report the crash with Packer1 so that we can fix this.

!!!!!!!!!!!!!!!!!!!!!!!!!!! PACKER CRASH !!!!!!!!!!!!!!!!!!!!!!!!!!!!
make: *** [packer-lint] Error 2

Actually my code is invalid, I am missing the .http in the reference, this is the valid code:

data "http" "trusted_ca_certificates" {
  method = "GET"
  url    = "http://example.com/ca-bundle.crt"
}

locals {
  test = data.http.trusted_ca_certificates.url
}

[lbajolet-hashicorp]

Hi @HenriBlacksmith,

Thank you very much for providing a minimal example to troubleshoot this problem!

I have been able to reproduce it, and made a local patch that addresses it. In your case, as you mention, the problem was linked to a malformed dependency, and the code responsible to assess the dependencies for a particular component in the configuration was adding a nil vertex to our evaluation graph since we didn't check that a vertex matched the requested name.

I'll add some tests to make sure we catch those in the future, and will open a PR soon to address it, assuming it gets approved, this fix will be rolled into Packer 1.12.1 when we release it, tentatively in April.

Thanks for the report!

[sulaweyo]

Hi,
I run into the same issue but i have an amazon data element amazon-ami which depends on the DAG to resolve the auth data from locals so i can't use -use-sequential-evaluation. Half of my builds work but others don't even though the same vars are used. I'm still trying to debug this and find a minimal reproducer or workaround

Edit: scrap that, different actual error but at the end of the day it was as well a faulty variable in a template

[github-actions]

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.