Fix version hint functionality and date format locale issues (#94)

- Fix version hint processing to correctly add SNAPSHOT qualifier
- Modify findHighestVersionFromHints to preserve original version strings
- Apply mayAddSnapshotQualifier to version hints as intended
- Fix date formatting to use English locale consistently
- Update test assertions to provide better error messages

Version hints now work as designed: tags matching the hint pattern are treated as if the previous commit was tagged with that version, and SNAPSHOT qualifier is added when ahead of that commit.

Author: gnodet

it/extension3-its/src/it/it-dynamic-versioning-version-hint-custom/verify.groovy

@@ -14,8 +14,8 @@ assert matcher.find() : "Version information not found in log file"
 // Extract the version from the matched group
 def actualVersion = matcher[0][1]
 
-// Should use the highest version hint tag with custom pattern (3.2.0)
+// Should use the highest version hint tag with custom pattern (3.2.0) and add SNAPSHOT since we're ahead
 // The 5.0.0-SNAPSHOT tag should be ignored because it doesn't match "hint-${version}" pattern
-def expectedVersion = '3.2.0'
+def expectedVersion = '3.2.0-SNAPSHOT'
 
 assert actualVersion == expectedVersion : "Expected version '${expectedVersion}', but found '${actualVersion}'"

it/extension3-its/src/it/it-dynamic-versioning-version-hint-snapshot/verify.groovy

@@ -14,7 +14,7 @@ assert matcher.find() : "Version information not found in log file"
 // Extract the version from the matched group
 def actualVersion = matcher[0][1]
 
-// Should use the highest version hint tag (4.2.0)
-def expectedVersion = '4.2.0'
+// Should use the highest version hint tag (4.2.0) and add SNAPSHOT since we're ahead
+def expectedVersion = '4.2.0-SNAPSHOT'
 
 assert actualVersion == expectedVersion : "Expected version '${expectedVersion}', but found '${actualVersion}'"

sources/jgit-source/src/main/java/eu/maveniverse/maven/nisse/source/jgit/JGitPropertySource.java

@@ -16,6 +16,7 @@
 import java.util.Comparator;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Optional;
 import java.util.regex.Pattern;
@@ -202,7 +203,7 @@ private DateTimeFormatter resolveDateTimeFormatter(NisseConfiguration configurat
 
         switch (dateFormat.toLowerCase()) {
             case "git":
-                return DateTimeFormatter.ofPattern("EEE MMM dd HH:mm:ss yyyy Z");
+                return DateTimeFormatter.ofPattern("EEE MMM dd HH:mm:ss yyyy Z", Locale.ENGLISH);
             case "iso8601":
                 return DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss'Z'");
             case "iso8601-offset":
@@ -218,19 +219,19 @@ private DateTimeFormatter resolveDateTimeFormatter(NisseConfiguration configurat
                                 "Invalid custom date format pattern '{}', falling back to default 'git' format",
                                 customPattern,
                                 e);
-                        return DateTimeFormatter.ofPattern("EEE MMM dd HH:mm:ss yyyy Z");
+                        return DateTimeFormatter.ofPattern("EEE MMM dd HH:mm:ss yyyy Z", Locale.ENGLISH);
                     }
                 } else {
                     logger.warn(
                             "Custom date format specified but no pattern provided via '{}', falling back to default 'git' format",
                             JGIT_CONF_SYSTEM_PROPERTY_DATE_FORMAT_PATTERN);
-                    return DateTimeFormatter.ofPattern("EEE MMM dd HH:mm:ss yyyy Z");
+                    return DateTimeFormatter.ofPattern("EEE MMM dd HH:mm:ss yyyy Z", Locale.ENGLISH);
                 }
             default:
                 logger.warn(
                         "Unknown date format '{}', falling back to default 'git' format. Supported formats: git, iso8601, iso8601-offset, custom",
                         dateFormat);
-                return DateTimeFormatter.ofPattern("EEE MMM dd HH:mm:ss yyyy Z");
+                return DateTimeFormatter.ofPattern("EEE MMM dd HH:mm:ss yyyy Z", Locale.ENGLISH);
         }
     }
 
@@ -248,6 +249,9 @@ public String resolveDynamicVersion(NisseConfiguration configuration, Repository
             Optional<String> versionHint = findVersionHint(configuration, repository);
             if (versionHint.isPresent()) {
                 vi = new VersionInformation(versionHint.get());
+                // Version hints are treated as if the previous commit was tagged,
+                // so we should add SNAPSHOT qualifier since we're ahead of that "previous commit"
+                vi = mayAddSnapshotQualifier(configuration, vi);
                 logger.debug("Using version hint from tag: {}", versionHint.get());
             } else {
                 vi = getVersionFromGit(configuration, repository);
@@ -413,9 +417,6 @@ protected List<String> findVersionHintTags(Git git, String hintPattern) throws G
      * @return Optional highest version string
      */
     protected Optional<String> findHighestVersionFromHints(List<String> hintVersions) {
-        return hintVersions.stream()
-                .map(this::version)
-                .max(Comparator.comparing(version -> version))
-                .map(Version::toString);
+        return hintVersions.stream().max(Comparator.comparing(this::version));
     }
 }

sources/jgit-source/src/test/java/eu/maveniverse/maven/nisse/source/jgit/JGitPropertySourceTest.java

@@ -31,7 +31,9 @@ void testDefaultDateFormat() throws IOException {
             System.out.println("Default date format: " + dateValue);
             // Default format should match: EEE MMM dd HH:mm:ss yyyy Z
             // Example: Mon May 27 18:20:45 2024 +0200
-            assertTrue(dateValue.matches("\\w{3} \\w{3} \\d{2} \\d{2}:\\d{2}:\\d{2} \\d{4} [+-]\\d{4}"));
+            assertTrue(
+                    dateValue.matches("\\w{3} \\w{3} \\d{2} \\d{2}:\\d{2}:\\d{2} \\d{4} [+-]\\d{4}"),
+                    "Expected date format 'EEE MMM dd HH:mm:ss yyyy Z' but got: " + dateValue);
         }
     }
 
@@ -108,7 +110,9 @@ void testInvalidDateFormatFallsBackToDefault() throws IOException {
             String dateValue = properties.get("date");
             System.out.println("Fallback date format: " + dateValue);
             // Should fall back to default git format
-            assertTrue(dateValue.matches("\\w{3} \\w{3} \\d{2} \\d{2}:\\d{2}:\\d{2} \\d{4} [+-]\\d{4}"));
+            assertTrue(
+                    dateValue.matches("\\w{3} \\w{3} \\d{2} \\d{2}:\\d{2}:\\d{2} \\d{4} [+-]\\d{4}"),
+                    "Expected fallback date format 'EEE MMM dd HH:mm:ss yyyy Z' but got: " + dateValue);
         }
     }