Git config verification: avoid mutating local git config and throw exception instead

.github/workflows/nebula.yml

@@ -26,6 +26,10 @@ jobs:
     name: Gradle Build without Publish
     steps:
       - uses: actions/checkout@v1
+      - name: Setup git user
+        run: |
+          git config --global user.name "$(git --no-pager log --format=format:'%an' -n 1)"
+          git config --global user.email "$(git --no-pager log --format=format:'%ae' -n 1)"
       - name: Set up JDK 8
         uses: actions/setup-java@v2
         with:

src/main/groovy/nebula/plugin/release/git/command/GitReadCommand.groovy

@@ -276,7 +276,6 @@ abstract class RevListCountHead  extends GitReadCommand {
  * ex. git rev-parse HEAD -> 8e6c4c925a54dbe827f043d21cd7a2a01b97fbac
  */
 abstract class RevParseHead extends GitReadCommand {
-
     @Override
     String obtain() {
         try {
@@ -312,9 +311,13 @@ abstract class GetGitConfigValue extends GitReadCommand {
     @Override
     String obtain() {
         try {
-            return executeGitCommand( "config", parameters.getGitConfigScope().get(), parameters.getGitConfigKey().get())
+            if(parameters.getGitConfigScope().isPresent()) {
+                return executeGitCommand( "config", parameters.getGitConfigScope().get(), parameters.getGitConfigKey().get())
+            } else {
+                return executeGitCommand( "config", parameters.getGitConfigKey().get())
+            }
         } catch (Exception e) {
-            logger.debug("Could not get git config {} {} {}", parameters.getGitConfigScope().get(), parameters.getGitConfigKey().get())
+            logger.debug("Could not get git config {} {}", parameters.getGitConfigScope().isPresent() ? parameters.gitConfigScope.get() : "", parameters.getGitConfigKey().get())
             return null
         }
     }

src/main/groovy/nebula/plugin/release/git/command/GitReadOnlyCommandUtil.groovy

@@ -1,6 +1,7 @@
 package nebula.plugin.release.git.command
 
 import nebula.plugin.release.git.model.TagRef
+import org.gradle.api.GradleException
 import org.gradle.api.provider.Provider
 import org.gradle.api.provider.ProviderFactory
 import org.slf4j.Logger
@@ -41,7 +42,7 @@ class GitReadOnlyCommandUtil implements Serializable {
         emailFromLogProvider = providers.of(EmailFromLog.class) {
             it.parameters.rootDir.set(rootDir)
         }
-        configureCommitterIfNecessary()
+        verifyGitConfig()
         currentBranchProvider = providers.of(CurrentBranch.class) {
             it.parameters.rootDir.set(rootDir)
         }
@@ -75,18 +76,22 @@ class GitReadOnlyCommandUtil implements Serializable {
 
     }
 
-    private void configureCommitterIfNecessary() {
+    private void verifyGitConfig() {
+        String username = getGitConfig('user.name')
+        String email = getGitConfig('user.email')
         String globalUsername = getGitConfig('--global', 'user.name')
         String globalEmail = getGitConfig('--global', 'user.email')
+        String systemUsername = getGitConfig('--system', 'user.name')
+        String systemEmail = getGitConfig('--system', 'user.email')
         String localUsername = getGitConfig('--local', 'user.name')
         String localEmail = getGitConfig('--local', 'user.email')
         String usernameFromLog = usernameFromLogProvider.isPresent() ? usernameFromLogProvider.get() : null
-        if(!globalUsername && !localUsername && usernameFromLog) {
-            setGitConfig("user.name", usernameFromLog)
+        if(!username && !globalUsername && !localUsername && !systemUsername && usernameFromLog) {
+            throw new GradleException("Git user.name is not set. Please configure git user.name globally, locally or system wide. You can learn more in https://git-scm.com/book/en/v2/Getting-Started-First-Time-Git-Setup")
         }
         String emailFromLog =  emailFromLogProvider.isPresent() ? emailFromLogProvider.get() : null
-        if(!globalEmail && !localEmail && emailFromLog) {
-            setGitConfig("user.email", emailFromLog)
+        if(!email && !globalEmail && !localEmail && !systemEmail && emailFromLog) {
+            throw new GradleException("Git user.email is not set. Please configure git user.email globally, locally or system wide. You can learn more in https://git-scm.com/book/en/v2/Getting-Started-First-Time-Git-Setup")
         }
     }
 
@@ -255,6 +260,23 @@ class GitReadOnlyCommandUtil implements Serializable {
             logger.debug("Could not get git config {} {} {}", scope, configKey)
             return null
         }
+    }    /**
+     * Returns a git config value for a given scope
+     * @param configKey
+     * @return
+     */
+    String getGitConfig(String configKey) {
+        try {
+            def getConfigValueProvider = providers.of(GetGitConfigValue.class) {
+                it.parameters.rootDir.set(rootDir)
+                it.parameters.gitConfigKey.set(configKey)
+            }
+            return getConfigValueProvider.get().toString()?.
+                    replaceAll("\n", "")?.toString()
+        } catch(Exception e) {
+            logger.debug("Could not get git config {} {}", configKey)
+            return null
+        }
     }
 
     /**