From 63636db470c718c3b99e490135990764508f8208 Mon Sep 17 00:00:00 2001
From: Erik Sipsma <erik@dagger.io>
Date: Fri, 13 Dec 2024 12:21:56 -0800
Subject: [PATCH] fix "return nil on err" cases and enable related linter
 (#9199)

Happened across an instance of incorrectly returning nil when err was
set while working on stuff. This fixes that and enables the nilerr
linter for catching these things, which revealed another occurence.

As far as I can tell these haven't been actively hurting us most likely
(the error cases are extremely unlikely to happen) but worth preventing
these spooky typos from happening again going forward.

Signed-off-by: Erik Sipsma <erik@sipsma.dev>
---
 core/directory.go                | 2 +-
 core/modulesource.go             | 2 +-
 engine/sources/httpdns/source.go | 2 +-
 modules/golangci/lint-config.yml | 1 +
 4 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/core/directory.go b/core/directory.go
index 2e83960a65..2003eabd40 100644
--- a/core/directory.go
+++ b/core/directory.go
@@ -135,7 +135,7 @@ func (dir *Directory) SetState(ctx context.Context, st llb.State) error {
 		buildkit.WithPassthrough(), // these spans aren't particularly interesting
 	)
 	if err != nil {
-		return nil
+		return err
 	}
 
 	dir.LLB = def.ToPB()
diff --git a/core/modulesource.go b/core/modulesource.go
index a5d0ead971..b774059ee0 100644
--- a/core/modulesource.go
+++ b/core/modulesource.go
@@ -572,7 +572,7 @@ func (src *ModuleSource) ModuleConfig(ctx context.Context) (*modules.ModuleConfi
 	configFile, err := contextDir.Self.File(ctx, filepath.Join(rootSubpath, modules.Filename))
 	if err != nil {
 		// no configuration for this module yet, so no name
-		return nil, false, nil
+		return nil, false, nil //nolint:nilerr
 	}
 	configBytes, err := configFile.Contents(ctx)
 	if err != nil {
diff --git a/engine/sources/httpdns/source.go b/engine/sources/httpdns/source.go
index 4d890f703b..9e876a8f75 100644
--- a/engine/sources/httpdns/source.go
+++ b/engine/sources/httpdns/source.go
@@ -162,7 +162,7 @@ func (hs *httpSourceHandler) CacheKey(ctx context.Context, g session.Group, inde
 
 	uh, err := hs.urlHash()
 	if err != nil {
-		return "", "", nil, false, nil
+		return "", "", nil, false, err
 	}
 
 	// look up metadata(previously stored headers) for that URL
diff --git a/modules/golangci/lint-config.yml b/modules/golangci/lint-config.yml
index ea6f772b30..02ef61aca8 100644
--- a/modules/golangci/lint-config.yml
+++ b/modules/golangci/lint-config.yml
@@ -27,6 +27,7 @@ linters:
     - unparam
     - whitespace
     - gomodguard
+    - nilerr
 
 issues:
   exclude-rules: