Use generate_target for timestamped changelog generator.

Telegram/build/changelog2appdata.py

@@ -9,8 +9,8 @@ def parse_changelog(changelog_path):
     version_re = re.compile(r'([\d.-]+)\s+(\w+)?\s*\((\d{2}.\d{2}\.\d{2})\)')
     entry_re = re.compile(r'-\s(.*)')
 
-    with open(changelog_path, "r") as f:
+    with open(changelog_path, "rb") as f:
-        changelog_lines = f.read().splitlines()
+        changelog_lines = f.read().decode('utf-8').splitlines()
 
     releases = []
     for l in changelog_lines:

Telegram/cmake/generate_appdata_changelog.cmake

@@ -7,18 +7,28 @@
 function(generate_appdata_changelog target_name changelog_path appdata_path)
     find_package(Python3 REQUIRED)
 
-    add_custom_target(${target_name}_appdata_changelog
+    set(gen_dst ${CMAKE_CURRENT_BINARY_DIR}/gen)
+    set(gen_timestamp ${gen_dst}/${target_name}_changelog.timestamp)
+    set(gen_files ${appdata_path})
+
+    add_custom_command(
+    OUTPUT
+        ${gen_timestamp}
+    BYPRODUCTS
+        ${gen_files}
+    COMMAND
         ${Python3_EXECUTABLE}
         ${submodules_loc}/build/changelog2appdata.py
         -c "${changelog_path}"
         -a "${appdata_path}"
         -n 10
+    COMMAND
+        echo 1> ${gen_timestamp}
     COMMENT "Generating AppData changelog (${target_name})"
     DEPENDS
         ${submodules_loc}/build/changelog2appdata.py
         ${changelog_path}
         ${appdata_path}
-    VERBATIM
     )
-    add_dependencies(${target_name} ${target_name}_appdata_changelog)
+    generate_target(${target_name} changelog ${gen_timestamp} "${gen_files}" ${gen_dst})
 endfunction()