From db95aea8556ca28b3dadf5f7133d0a429551787d Mon Sep 17 00:00:00 2001
From: Jeffrey Price <jprice@impulse.com>
Date: Thu, 4 Oct 2018 09:36:16 -0400
Subject: [PATCH] Fix the ability of the 'gitBranchExpression' project property
 to override git branch detection.

When the environment variable expression provided by
'gitBranchExpression' resolves to some branch name, that was being
ignored in favor of the git branch detected by reading the local git
metadata. Now the local git branch is only used if that variable is
missing or doesn't fully resolve.
---
 .../maven/gitflowhelper/ScmUtils.java         | 56 ++++++++++---------
 1 file changed, 31 insertions(+), 25 deletions(-)

diff --git a/src/main/java/com/e_gineering/maven/gitflowhelper/ScmUtils.java b/src/main/java/com/e_gineering/maven/gitflowhelper/ScmUtils.java
index abf0582..9927a5f 100644
--- a/src/main/java/com/e_gineering/maven/gitflowhelper/ScmUtils.java
+++ b/src/main/java/com/e_gineering/maven/gitflowhelper/ScmUtils.java
@@ -87,15 +87,41 @@ public static String resolveUrlOrExpression(final MavenProject project) {
     /**
      * Attempts to resolve the current branch of the build.
      */
-    public GitBranchInfo resolveBranchInfo(final String gitBranchExpression)
-    {
+    public GitBranchInfo resolveBranchInfo(final String gitBranchExpression) {
         // Start off with the name or expression provided from the config parameter.
         // Remember, the config parameter may be `null` (it is by default).
         String branchNameOrExpression = gitBranchExpression;
 
+        // Make sure we have a non-null value. (may have been passed in from the @Parameter)
+        if (branchNameOrExpression == null) {
+            log.debug("Git branch expression was null, defaulting to: " + DEFAULT_BRANCH_EXPRESSION);
+            branchNameOrExpression = DEFAULT_BRANCH_EXPRESSION;
+        }
+
+        // Now force it to resolve any properties.
+        String resolvedBranchName = PropertyResolver.resolveValue(branchNameOrExpression, project.getProperties(), systemEnvVars);
+
+        // It's possible that we were unable to expand all the properties.
+        // In this case we'll try reading the git branch name by invoking the git command.
+        ExpansionBuffer eb = new ExpansionBuffer(resolvedBranchName);
+        if (eb.hasMoreLegalPlaceholders()) {
+            resolvedBranchName = getBranchNameFromGit();
+            log.debug("Git branch expression couldn't be resolved, using branch name from git metadata: " + resolvedBranchName);
+        }
+
+        if (!branchNameOrExpression.equals(resolvedBranchName) || log.isDebugEnabled()) { // Resolves Issue #9
+            if (log.isDebugEnabled()) {
+                log.debug("Resolved gitBranchExpression: '" + gitBranchExpression + "' to '" + resolvedBranchName + "'");
+            }
+        }
+
+        return resolveBranchType(resolvedBranchName);
+    }
 
+    private String getBranchNameFromGit() {
         String connectionUrl = resolveUrlOrExpression(project);
 
+        String result = null;
         try {
             ScmRepository repository = scmManager.makeScmRepository(connectionUrl);
             if (!GitScmProviderRepository.PROTOCOL_GIT.equals(scmManager.getProviderByRepository(repository).getScmType())) {
@@ -109,7 +135,7 @@ public GitBranchInfo resolveBranchInfo(final String gitBranchExpression)
             ScmLogDispatcher scmLogger = new ScmLogDispatcher();
 
             try {
-                branchNameOrExpression = GitBranchCommand.getCurrentBranch(scmLogger, gitScmProviderRepository, fileSet);
+                result = GitBranchCommand.getCurrentBranch(scmLogger, gitScmProviderRepository, fileSet);
             } catch (ScmException scme) {
                 log.debug("Exception attempting to resolve a local branch. Attempting detached HEAD resolution");
 
@@ -153,7 +179,7 @@ public GitBranchInfo resolveBranchInfo(final String gitBranchExpression)
                 // Detached head resolution was successful.
                 // Either we iterated once, or all of the subsequent types were resolved to the same type as the
                 // first branch, and there was only one of those branches which may have been a uniquely versioned branch.
-                branchNameOrExpression = name;
+                result = name;
             }
         } catch (ScmException scme) {
             // Only do the following if the SCM resolution fails miserably.
@@ -161,27 +187,7 @@ public GitBranchInfo resolveBranchInfo(final String gitBranchExpression)
         } catch (IllegalArgumentException iae) {
             log.debug("IllegalArgumentException likely the result of the <scm> block missing from the pom.xml", iae);
         }
-
-        // Make sure we have a non-null value. (may have been passed in from the @Parameter)
-        if (branchNameOrExpression == null) {
-            branchNameOrExpression = DEFAULT_BRANCH_EXPRESSION;
-        }
-
-        // Now force it to resolve any properties.
-        String resolvedBranchName = PropertyResolver.resolveValue(branchNameOrExpression, project.getProperties(), systemEnvVars);
-
-        if (!branchNameOrExpression.equals(resolvedBranchName) || log.isDebugEnabled()) { // Resolves Issue #9
-            if (log.isDebugEnabled()) {
-                log.debug("Resolved gitBranchExpression: '" + gitBranchExpression + " to '" + resolvedBranchName + "'");
-            }
-        }
-        // It's possible that we were unable to expand all the properties.
-        ExpansionBuffer eb = new ExpansionBuffer(resolvedBranchName);
-        if (eb.hasMoreLegalPlaceholders()) {
-            resolvedBranchName = null; // Force it to resolve as UNDEFINED.
-        }
-
-        return resolveBranchType(resolvedBranchName);
+        return result;
     }
 
     private GitBranchInfo resolveBranchType(String branchName) {