Work around --gc failure on Windows <= 10

This applies two related fixes/improvements:

* The --gc now keeps empty `_resources/_gen/images` etc folders, even if empty. This should have been the behaviour
from the start.
* Also, if removal of an empty dir on Windows fails with the "used by another process" error, just ignore it for now.

Fixes #10781

diff --git a/cache/filecache/filecache_pruner.go b/cache/filecache/filecache_pruner.go
index 5734af1995dcb814b0eb8b64c60619a9975631ab..41aec15d3cdcbb8d942fe7d5eb79ed70fc7ba191 100644 (file)
--- a/cache/filecache/filecache_pruner.go
+++ b/cache/filecache/filecache_pruner.go
@@ -17,6 +17,8 @@ import (
        "fmt"
        "io"
        "os"
+       "runtime"
+       "strings"
 
        "github.com/gohugoio/hugo/common/herrors"
        "github.com/gohugoio/hugo/hugofs"
@@ -66,6 +68,7 @@ func (c *Cache) Prune(force bool) (int, error) {
 
                if info.IsDir() {
                        f, err := c.Fs.Open(name)
+
                        if err != nil {
                                // This cache dir may not exist.
                                return nil
@@ -74,7 +77,24 @@ func (c *Cache) Prune(force bool) (int, error) {
                        _, err = f.Readdirnames(1)
                        if err == io.EOF {
                                // Empty dir.
-                               err = c.Fs.Remove(name)
+                               if name == "." {
+                                       // e.g. /_gen/images -- keep it even if empty.
+                                       err = nil
+                               } else {
+                                       err = c.Fs.Remove(name)
+                                       if err != nil {
+                                               if runtime.GOOS == "windows" {
+                                                       if strings.Contains(err.Error(), "used by another process") {
+                                                               // See https://github.com/gohugoio/hugo/issues/10781
+                                                               // This is a known issue on Windows with Go 1.20.
+                                                               // There's not much we can do about it.
+                                                               // So just return nil.
+                                                               err = nil
+
+                                                       }
+                                               }
+                                       }
+                               }
                        }
 
                        if err != nil && !herrors.IsNotExist(err) {

diff --git a/cache/filecache/integration_test.go b/cache/filecache/integration_test.go
new file mode 100644 (file)
index 0000000..eaddf9d
--- /dev/null
+++ b/cache/filecache/integration_test.go
@@ -0,0 +1,102 @@
+// Copyright 2023 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package filecache_test
+
+import (
+       "path/filepath"
+       "runtime"
+       "testing"
+       "time"
+
+       qt "github.com/frankban/quicktest"
+       "github.com/gohugoio/hugo/hugolib"
+)
+
+// See issue #10781. That issue wouldn't have been triggered if we kept
+// the empty root directories (e.g. _resources/gen/images).
+// It's still an upstream Go issue that we also need to handle, but
+// this is a test for the first part.
+func TestPruneShouldPreserveEmptyCacheRoots(t *testing.T) {
+       files := `
+-- hugo.toml --
+baseURL = "https://example.com"
+-- content/_index.md --
+---
+title: "Home"
+---
+
+`
+
+       b := hugolib.NewIntegrationTestBuilder(
+               hugolib.IntegrationTestConfig{T: t, TxtarString: files, RunGC: true, NeedsOsFS: true},
+       ).Build()
+
+       _, err := b.H.BaseFs.ResourcesCache.Stat(filepath.Join("_gen", "images"))
+
+       b.Assert(err, qt.IsNil)
+
+}
+
+func TestPruneImages(t *testing.T) {
+       files := `
+-- hugo.toml --
+baseURL = "https://example.com"
+[caches]
+[caches.images]
+maxAge = "200ms"
+dir = ":resourceDir/_gen"
+-- content/_index.md --
+---
+title: "Home"
+---
+-- assets/a/pixel.png --
+iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNkYPhfDwAChwGA60e6kgAAAABJRU5ErkJggg==
+-- layouts/index.html --
+{{ $img := resources.GetMatch "**.png" }}
+{{ $img = $img.Resize "3x3" }}
+{{ $img.RelPermalink }}
+
+
+
+`
+
+       b := hugolib.NewIntegrationTestBuilder(
+               hugolib.IntegrationTestConfig{T: t, TxtarString: files, RunGC: true, NeedsOsFS: true},
+       ).Build()
+
+       b.Assert(b.GCCount, qt.Equals, 0)
+
+       imagesCacheDir := filepath.Join("_gen", "images")
+       _, err := b.H.BaseFs.ResourcesCache.Stat(imagesCacheDir)
+
+       b.Assert(err, qt.IsNil)
+
+       // TODO(bep) we need a way to test full rebuilds.
+       // For now, just sleep a little so the cache elements expires.
+       time.Sleep(300 * time.Millisecond)
+
+       b.RenameFile("assets/a/pixel.png", "assets/b/pixel2.png").Build()
+       b.Assert(b.GCCount, qt.Equals, 1)
+       // Build it again to GC the empty a dir.
+       b.Build()
+       if runtime.GOOS != "windows" {
+               // See issue #58860 -- this sometimes fails on Windows,
+               // but the empty directory will be removed on the next run.
+               _, err = b.H.BaseFs.ResourcesCache.Stat(filepath.Join(imagesCacheDir, "a"))
+               b.Assert(err, qt.Not(qt.IsNil))
+       }
+       _, err = b.H.BaseFs.ResourcesCache.Stat(imagesCacheDir)
+       b.Assert(err, qt.IsNil)
+
+}

diff --git a/hugolib/integrationtest_builder.go b/hugolib/integrationtest_builder.go
index f0e3c504dae073e2622948a5071cffb8202a62e3..8bd458bc141fad09c26606aeecf628ad45329f1f 100644 (file)
--- a/hugolib/integrationtest_builder.go
+++ b/hugolib/integrationtest_builder.go
@@ -84,6 +84,7 @@ type IntegrationTestBuilder struct {
        renamedFiles []string
 
        buildCount int
+       GCCount    int
        counters   *testCounters
        logBuff    lockingBuffer
 
@@ -193,6 +194,9 @@ func (s *IntegrationTestBuilder) Build() *IntegrationTestBuilder {
        if s.Cfg.Verbose || err != nil {
                fmt.Println(s.logBuff.String())
        }
+       if s.Cfg.RunGC {
+               s.GCCount, err = s.H.GC()
+       }
        s.Assert(err, qt.IsNil)
        return s
 }
@@ -263,6 +267,7 @@ func (s *IntegrationTestBuilder) RenameFile(old, new string) *IntegrationTestBui
        absNewFilename := s.absFilename(new)
        s.renamedFiles = append(s.renamedFiles, absOldFilename)
        s.createdFiles = append(s.createdFiles, absNewFilename)
+       s.Assert(s.fs.Source.MkdirAll(filepath.Dir(absNewFilename), 0777), qt.IsNil)
        s.Assert(s.fs.Source.Rename(absOldFilename, absNewFilename), qt.IsNil)
        return s
 }
@@ -488,6 +493,9 @@ type IntegrationTestConfig struct {
        // Whether it needs the real file system (e.g. for js.Build tests).
        NeedsOsFS bool
 
+       // Whether to run GC after each build.
+       RunGC bool
+
        // Do not remove the temp dir after the test.
        PrintAndKeepTempDir bool