logger: add git branch name to the log

src/lib/version/version.c

@@ -156,6 +156,11 @@ uint32_t px4_firmware_version(void)
 	return version_tag_to_number(PX4_GIT_TAG_STR);
 }
 
+const char *px4_firmware_git_branch(void)
+{
+	return PX4_GIT_BRANCH_NAME;
+}
+
 uint32_t px4_board_version(void)
 {
 #if defined(__PX4_NUTTX)

src/lib/version/version.h

@@ -118,6 +118,12 @@ __EXPORT const char *px4_toolchain_version(void);
  */
 __EXPORT const char *px4_firmware_version_string(void);
 
+/**
+ * get the git branch name (can be empty, for example if HEAD points to a tag)
+ */
+__EXPORT const char *px4_firmware_git_branch(void);
+
+
 /**
  * Firmware version in binary form (first part of the git tag)
  */

src/modules/logger/logger.cpp

@@ -1656,6 +1656,12 @@ void Logger::write_version()
 	write_info("sys_os_name", px4_os_name());
 	const char *os_version = px4_os_version_string();
 
+	const char *git_branch = px4_firmware_git_branch();
+
+	if (git_branch && git_branch[0]) {
+		write_info("ver_sw_branch", git_branch);
+	}
+
 	if (os_version) {
 		write_info("sys_os_ver", os_version);
 	}