From 50bc89bab17de2a954d9acfff957b279aede4889 Mon Sep 17 00:00:00 2001
From: Dmitry Kalinkin <dmitry.kalinkin@gmail.com>
Date: Tue, 23 Jul 2024 17:03:49 -0400
Subject: [PATCH] cmake: set CMAKE_PROJECT_VERSION from git, add it back to
 thisepic.sh (#758)

### Briefly, what does this PR introduce?
This uses same code as in EICrecon. This partially undoes of #733,
geometry version is useful.

### What kind of change does this PR introduce?
- [ ] Bug fix (issue #__)
- [x] New feature (issue #__)
- [ ] Documentation update
- [ ] Other: __

### Please check if this PR fulfills the following:
- [ ] Tests for the changes have been added
- [ ] Documentation has been added / updated
- [ ] Changes have been communicated to collaborators

### Does this PR introduce breaking changes? What changes might users
need to make to their code?
No

### Does this PR change default behavior?
No

---------

Co-authored-by: Wouter Deconinck <wdconinc@gmail.com>
---
 CMakeLists.txt            | 18 ++++++++++++------
 cmake/git_version.cmake   | 29 +++++++++++++++++++++++++++++
 templates/epic.xml.jinja2 |  1 +
 templates/thisepic.sh.in  |  1 +
 templates/version.xml.in  |  4 ++++
 5 files changed, 47 insertions(+), 6 deletions(-)
 create mode 100644 cmake/git_version.cmake
 create mode 100644 templates/version.xml.in

diff --git a/CMakeLists.txt b/CMakeLists.txt
index fa06a7105..49e5778d3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -8,6 +8,10 @@ PROJECT(epic
   DESCRIPTION "DD4hep Geometry Description of the EPIC Experiment"
   )
 
+# Set version based on git
+include(cmake/git_version.cmake)
+set_git_version(CMAKE_PROJECT_VERSION)
+
 # C++ standard
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD 17 CACHE STRING "Set the C++ standard to be used")
@@ -101,14 +105,16 @@ install(DIRECTORY calibrations/
     )
 
 #-----------------------------------------------------------------------------------
-# Configure and install detector setup script
+# Configure and install compact/version.xml
 #
-execute_process(
-  COMMAND git rev-parse --abbrev-ref HEAD
-  WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
-  OUTPUT_VARIABLE GIT_BRANCH
-  OUTPUT_STRIP_TRAILING_WHITESPACE
+configure_file(templates/version.xml.in ${CMAKE_CURRENT_BINARY_DIR}/version.xml @ONLY)
+install(FILES ${CMAKE_CURRENT_BINARY_DIR}/version.xml
+    DESTINATION ${CMAKE_INSTALL_DATADIR}/${PROJECT_NAME}/compact
 )
+
+#-----------------------------------------------------------------------------------
+# Configure and install detector setup script
+#
 configure_file(templates/thisepic.sh.in ${CMAKE_CURRENT_BINARY_DIR}/thisepic.sh @ONLY)
 install(FILES ${CMAKE_CURRENT_BINARY_DIR}/thisepic.sh
     DESTINATION ${CMAKE_INSTALL_BINDIR}
diff --git a/cmake/git_version.cmake b/cmake/git_version.cmake
new file mode 100644
index 000000000..98e013cfe
--- /dev/null
+++ b/cmake/git_version.cmake
@@ -0,0 +1,29 @@
+# Determine version from git describe cmake-lint: disable=C0103
+macro(set_git_version VERSION)
+  if(NOT Git_Found)
+    find_package(Git)
+  endif()
+
+  if(GIT_EXECUTABLE)
+    # Generate a git-describe version string from Git repository tags
+    execute_process(
+      COMMAND ${GIT_EXECUTABLE} describe --tags --dirty --match "v*"
+      WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+      OUTPUT_VARIABLE GIT_DESCRIBE_VERSION
+      RESULT_VARIABLE GIT_DESCRIBE_ERROR_CODE
+      OUTPUT_STRIP_TRAILING_WHITESPACE)
+    if(NOT GIT_DESCRIBE_ERROR_CODE)
+      set(${VERSION} ${GIT_DESCRIBE_VERSION})
+    endif()
+  endif()
+
+  # Final fallback: Just use a bogus version string that is semantically older
+  # than anything else and spit out a warning to the developer.
+  if(NOT DEFINED ${VERSION})
+    set(${VERSION} v0.0.0-unknown)
+    message(
+      WARNING
+        "Failed to determine VERSION from Git tags. Using default version \"${${VERSION}}\"."
+    )
+  endif()
+endmacro()
diff --git a/templates/epic.xml.jinja2 b/templates/epic.xml.jinja2
index ad376206d..0472526f2 100644
--- a/templates/epic.xml.jinja2
+++ b/templates/epic.xml.jinja2
@@ -48,6 +48,7 @@
     <include ref="${DETECTOR_PATH}/compact/far_forward/definitions.xml" />
     <include ref="${DETECTOR_PATH}/compact/far_backward/definitions.xml" />
     <include ref="${DETECTOR_PATH}/compact/definitions.xml" />
+    <include ref="${DETECTOR_PATH}/compact/version.xml"/>
     <include ref="${DD4hepINSTALL}/DDDetectors/compact/detector_types.xml"/>
   </define>
 
diff --git a/templates/thisepic.sh.in b/templates/thisepic.sh.in
index 9a6013f05..f3ef9fde5 100644
--- a/templates/thisepic.sh.in
+++ b/templates/thisepic.sh.in
@@ -3,6 +3,7 @@
 export DETECTOR=@PROJECT_NAME@
 export DETECTOR_PATH=@CMAKE_INSTALL_FULL_DATADIR@/@PROJECT_NAME@
 export DETECTOR_CONFIG=${1:-@PROJECT_NAME@}
+export DETECTOR_VERSION=@CMAKE_PROJECT_VERSION@
 
 ## Warn is not the right name (this script is sourced, hence $1)
 if [[ "$(basename ${BASH_SOURCE[0]})" != "thisepic.sh" ]]; then
diff --git a/templates/version.xml.in b/templates/version.xml.in
new file mode 100644
index 000000000..6398540f7
--- /dev/null
+++ b/templates/version.xml.in
@@ -0,0 +1,4 @@
+<!-- SPDX-License-Identifier: LGPL-3.0-or-later -->
+<!-- Copyright (C) 2024 Dmitry Kalinkin -->
+
+    <constant name="epic_version" value="@CMAKE_PROJECT_VERSION@" />