Merge pull request #5905 from jerbob92/feature/only-call-pip-compile-once

Only call pip compile once

Author: deivid-rodriguez

python/lib/dependabot/python/file_updater/pip_compile_file_updater.rb

@@ -81,12 +81,6 @@ def compile_new_requirement_files
                 "#{SharedHelpers.escape_command(version_part)}",
                 allow_unsafe_shell_command: true
               )
-              # Run pip-compile a second time, without an update argument, to
-              # ensure it resets the right comments.
-              run_pip_compile_command(
-                "pyenv exec pip-compile #{pip_compile_options(filename)} " \
-                "#{filename}"
-              )
             end
 
             # Remove any .python-version file before parsing the reqs

python/lib/dependabot/python/update_checker/pip_compile_version_resolver.rb

@@ -80,9 +80,17 @@ def fetch_latest_resolvable_version_string(requirement:)
                   run_pip_compile_command(
                     "pyenv exec pip-compile -v #{pip_compile_options(filename)} -P #{dependency.name} #{filename}"
                   )
-                  # Run pip-compile a second time, without an update argument,
-                  # to ensure it handles markers correctly
-                  write_original_manifest_files unless dependency.top_level?
+
+                  next if dependency.top_level?
+
+                  # Run pip-compile a second time for transient dependencies
+                  # to make sure we do not update dependencies that are
+                  # superfluous. pip-compile does not detect these when
+                  # updating a specific dependency with the -P option.
+                  # Running pip-compile a second time will automatically remove
+                  # superfluous dependencies. Dependabot then marks those with
+                  # update_not_possible.
+                  write_original_manifest_files
                   run_pip_compile_command(
                     "pyenv exec pip-compile #{pip_compile_options(filename)} #{filename}"
                   )