ci: add script to fix go test caching

.github/workflows/pr_test.yml

@@ -132,10 +132,14 @@ jobs:
           name: config-artifact-${{ github.sha }}
       - name: "Move Config"
         run: mv config.toml pkg/config/config.toml
-      # NOTE: Windows should fail quietly for 'test' pre-requisite target.
-      # On Windows, executing `make config` works fine.
-      # But via GitHub Actions the ../../scripts/config.sh isn't run.
-      # This is because you can't nest PowerShell instances.
+      - name: "Modify git cloned repo files 'modified' times"
+        run: go run ./scripts/go-test-cache/main.go
+      # NOTE: Windows should fail quietly running pre-requisite target of `test`.
+      #
+      # On Windows, executing `make config` directly works fine.
+      # But when `config` is a pre-requisite to running `test`, it fails.
+      # But only when run via GitHub Actions.
+      # The ../../scripts/config.sh isn't run because you can't nest PowerShell instances.
       # Each GitHub Action 'run' step is a PowerShell instance.
       # And each instance is run as: powershell.exe -command ". '...'"
       - name: "Test suite"

scripts/go-test-cache/go.mod

@@ -0,0 +1,3 @@
+module go-test-cache
+
+go 1.20

scripts/go-test-cache/main.go

@@ -0,0 +1,111 @@
+// This script is based on https://github.com/airplanedev/blog-examples/blob/main/go-test-caching/update_file_timestamps.py?ref=airplane.ghost.io
+// and was generated automatically using AI.
+package main
+
+import (
+	"crypto/sha1"
+	"io"
+	"log"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+	"time"
+)
+
+const (
+	BUF_SIZE    = 65536
+	BASE_DATE   = 1684178360
+	TIME_FORMAT = "2006-01-02 15:04:05"
+)
+
+func main() {
+	repoRoot := "."
+	allDirs := make([]string, 0)
+
+	err := filepath.Walk(repoRoot, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+
+		if info.IsDir() {
+			dirPath := filepath.Join(repoRoot, path)
+			relPath, _ := filepath.Rel(repoRoot, dirPath)
+
+			if strings.HasPrefix(relPath, ".") {
+				return nil
+			}
+
+			allDirs = append(allDirs, dirPath)
+		} else {
+			filePath := filepath.Join(repoRoot, path)
+			relPath, _ := filepath.Rel(repoRoot, filePath)
+
+			if strings.HasPrefix(relPath, ".") {
+				return nil
+			}
+
+			sha1Hash, err := getFileSHA1(filePath)
+			if err != nil {
+				return err
+			}
+
+			modTime := getModifiedTime(sha1Hash)
+
+			log.Printf("Setting modified time of file %s to %s\n", relPath, modTime.Format(TIME_FORMAT))
+			err = os.Chtimes(filePath, modTime, modTime)
+			if err != nil {
+				return err
+			}
+		}
+
+		return nil
+	})
+	if err != nil {
+		log.Fatal("Error:", err)
+	}
+
+	sort.Slice(allDirs, func(i, j int) bool {
+		return len(allDirs[i]) > len(allDirs[j]) || (len(allDirs[i]) == len(allDirs[j]) && allDirs[i] < allDirs[j])
+	})
+
+	for _, dirPath := range allDirs {
+		relPath, _ := filepath.Rel(repoRoot, dirPath)
+
+		log.Printf("Setting modified time of directory %s to %s\n", relPath, time.Unix(BASE_DATE, 0).Format(TIME_FORMAT))
+		err := os.Chtimes(dirPath, time.Unix(BASE_DATE, 0), time.Unix(BASE_DATE, 0))
+		if err != nil {
+			log.Fatal("Error:", err)
+		}
+	}
+
+	log.Println("Done")
+}
+
+func getFileSHA1(filePath string) (string, error) {
+	file, err := os.Open(filePath)
+	if err != nil {
+		return "", err
+	}
+	defer file.Close()
+
+	hash := sha1.New()
+	if _, err := io.CopyBuffer(hash, file, make([]byte, BUF_SIZE)); err != nil {
+		return "", err
+	}
+
+	return string(hash.Sum(nil)), nil
+}
+
+func getModifiedTime(sha1Hash string) time.Time {
+	hashBytes := []byte(sha1Hash)
+	lastFiveBytes := hashBytes[:5]
+	lastFiveValue := int64(0)
+
+	for _, b := range lastFiveBytes {
+		lastFiveValue = (lastFiveValue << 8) + int64(b)
+	}
+
+	modTime := BASE_DATE - (lastFiveValue % 10000)
+	return time.Unix(modTime, 0)
+}