Fix builds from CI showing up as modified (#4384)

This change also adds a new environment variable used while building: `CHATTERINO_REQUIRE_CLEAN_GIT` which, if set, will error out during your build's GIT stage.
This is used in CI to ensure we don't accidentally introduce a change that would result in builds showing up as "modified" again.

Co-authored-by: Rasmus Karlsson <rasmus.karlsson@pajlada.com>

cmake/GIT.cmake

@@ -9,7 +9,7 @@
 #   If the git binary is found and the git work tree is intact, GIT_RELEASE is worked out using the `git describe` command
 #   The value of GIT_RELEASE can be overriden by defining the GIT_RELEASE environment variable
 # GIT_MODIFIED
-#	If the git binary is found and the git work tree is intact, GIT_MODIFIED is worked out by checking if output of `git status --porcelain -z` command is empty
+#   If the git binary is found and the git work tree is intact, GIT_MODIFIED is worked out by checking if output of `git status --porcelain -z` command is empty
 #   The value of GIT_MODIFIED cannot be overriden
 
 find_package(Git)
@@ -19,67 +19,75 @@ set(GIT_COMMIT "GIT-REPOSITORY-NOT-FOUND")
 set(GIT_RELEASE "${PROJECT_VERSION}")
 set(GIT_MODIFIED 0)
 
-if (DEFINED ENV{CHATTERINO_SKIP_GIT_GEN})
+if(DEFINED ENV{CHATTERINO_SKIP_GIT_GEN})
     return()
-endif ()
+endif()
 
-if (GIT_EXECUTABLE)
+if(GIT_EXECUTABLE)
     execute_process(
-            COMMAND ${GIT_EXECUTABLE} rev-parse --is-inside-work-tree
-            WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
-            RESULT_VARIABLE GIT_REPOSITORY_NOT_FOUND
-            OUTPUT_QUIET
-            ERROR_QUIET
+        COMMAND ${GIT_EXECUTABLE} rev-parse --is-inside-work-tree
+        WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+        RESULT_VARIABLE GIT_REPOSITORY_NOT_FOUND
+        OUTPUT_QUIET
+        ERROR_QUIET
     )
-    if (GIT_REPOSITORY_NOT_FOUND)
+
+    if(GIT_REPOSITORY_NOT_FOUND)
         set(GIT_REPOSITORY_FOUND 0)
-    else ()
+    else()
         set(GIT_REPOSITORY_FOUND 1)
     endif()
 
-    if (GIT_REPOSITORY_FOUND)
+    if(GIT_REPOSITORY_FOUND)
         execute_process(
-                COMMAND ${GIT_EXECUTABLE} rev-parse --short HEAD
-                WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
-                OUTPUT_VARIABLE GIT_HASH
-                OUTPUT_STRIP_TRAILING_WHITESPACE
+            COMMAND ${GIT_EXECUTABLE} rev-parse --short HEAD
+            WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+            OUTPUT_VARIABLE GIT_HASH
+            OUTPUT_STRIP_TRAILING_WHITESPACE
         )
 
         execute_process(
-                COMMAND ${GIT_EXECUTABLE} rev-parse HEAD
-                WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
-                OUTPUT_VARIABLE GIT_COMMIT
-                OUTPUT_STRIP_TRAILING_WHITESPACE
+            COMMAND ${GIT_EXECUTABLE} rev-parse HEAD
+            WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+            OUTPUT_VARIABLE GIT_COMMIT
+            OUTPUT_STRIP_TRAILING_WHITESPACE
         )
 
         execute_process(
-                COMMAND ${GIT_EXECUTABLE} describe
-                WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
-                OUTPUT_VARIABLE GIT_RELEASE
-                OUTPUT_STRIP_TRAILING_WHITESPACE
+            COMMAND ${GIT_EXECUTABLE} describe
+            WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+            OUTPUT_VARIABLE GIT_RELEASE
+            OUTPUT_STRIP_TRAILING_WHITESPACE
         )
 
         execute_process(
-                COMMAND ${GIT_EXECUTABLE} status --porcelain -z
-                WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
-                OUTPUT_VARIABLE GIT_MODIFIED_OUTPUT
-                OUTPUT_STRIP_TRAILING_WHITESPACE
+            COMMAND ${GIT_EXECUTABLE} status --porcelain -z
+            WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+            OUTPUT_VARIABLE GIT_MODIFIED_OUTPUT
+            OUTPUT_STRIP_TRAILING_WHITESPACE
         )
-    endif (GIT_REPOSITORY_FOUND)
-endif (GIT_EXECUTABLE)
+    endif(GIT_REPOSITORY_FOUND)
+endif(GIT_EXECUTABLE)
+
+if(GIT_MODIFIED_OUTPUT)
+    if(DEFINED ENV{CHATTERINO_REQUIRE_CLEAN_GIT})
+        message(STATUS "git status --porcelain -z\n${GIT_MODIFIED_OUTPUT}")
+        message(FATAL_ERROR "Git repository was expected to be clean, but modifications were found!")
+    endif()
 
-if (GIT_MODIFIED_OUTPUT)
     set(GIT_MODIFIED 1)
-endif ()
+endif()
 
-if (DEFINED ENV{GIT_HASH})
+if(DEFINED ENV{GIT_HASH})
     set(GIT_HASH "$ENV{GIT_HASH}")
-endif ()
-if (DEFINED ENV{GIT_COMMIT})
+endif()
+
+if(DEFINED ENV{GIT_COMMIT})
     set(GIT_COMMIT "$ENV{GIT_COMMIT}")
-endif ()
-if (DEFINED ENV{GIT_RELEASE})
+endif()
+
+if(DEFINED ENV{GIT_RELEASE})
     set(GIT_RELEASE "$ENV{GIT_RELEASE}")
-endif ()
+endif()
 
 message(STATUS "Injected git values: ${GIT_COMMIT} (${GIT_RELEASE}) modified: ${GIT_MODIFIED}")