fix: use a patch for rerender (#22)

* fix: use a patch for rerender

* fix: sync perms and stage properly

* fix: wrong git diff syntax

* fix: strip newlines and spaces

* test: debug what is going on here

* fix: do not cache docker build for now

Author: beckermr

.github/workflows/tests.yml

@@ -60,13 +60,11 @@ jobs:
           push: false
           load: true
           tags: conda-forge-feedstock-ops:test
-          cache-from: type=gha
-          cache-to: type=gha,mode=max
-
-      - name: run tests
-        run: |
-          pytest -vvs tests
 
       - name: ensure cli runs
         run: |
           conda-forge-feedstock-ops-container --help
+
+      - name: run tests
+        run: |
+          pytest -vvs tests

conda_forge_feedstock_ops/__main__.py

@@ -113,30 +113,40 @@ def _run_bot_task(func, *, log_level, existing_feedstock_node_attrs, **kwargs):
         print(dumps(ret))
 
 
-def _execute_git_cmds_and_report(*, cmds, cwd, msg):
+def _execute_git_cmds_and_report(*, cmds, cwd, msg, ignore_stderr=False):
     logger = logging.getLogger("conda_forge_feedstock_ops.container")
 
     try:
         _output = ""
+        _output_stderr = ""
         for cmd in cmds:
             gitret = subprocess.run(
                 cmd,
                 cwd=cwd,
                 stdout=subprocess.PIPE,
-                stderr=subprocess.STDOUT,
+                stderr=subprocess.PIPE if ignore_stderr else subprocess.STDOUT,
                 text=True,
             )
             logger.debug("git command %r output: %s", cmd, gitret.stdout)
             _output += gitret.stdout
+            if ignore_stderr:
+                _output_stderr += gitret.stderr
             gitret.check_returncode()
     except Exception as e:
-        logger.error("%s\noutput: %s", msg, _output, exc_info=e)
+        logger.error(
+            "%s\noutput: %s\nstderr: %s",
+            msg,
+            _output,
+            _output_stderr if ignore_stderr else "<in output>",
+            exc_info=e,
+        )
         raise e
 
+    return _output
+
 
 def _rerender_feedstock(*, timeout):
     from conda_forge_feedstock_ops.os_utils import (
-        chmod_plus_rwX,
         get_user_execute_permissions,
         reset_permissions_with_user_execute,
         sync_dirs,
@@ -192,6 +202,13 @@ def _rerender_feedstock(*, timeout):
             msg="git init failed for rerender",
         )
 
+        prev_commit = _execute_git_cmds_and_report(
+            cmds=[["git", "rev-parse", "HEAD"]],
+            cwd=fs_dir,
+            msg="git rev-parse HEAD failed for rerender prev commit",
+            ignore_stderr=True,
+        ).strip()
+
         if timeout is not None:
             kwargs = {"timeout": timeout}
         else:
@@ -212,16 +229,38 @@ def _rerender_feedstock(*, timeout):
                 msg="git status failed for rerender",
             )
 
-        # if something changed, copy back the new feedstock
         if msg is not None:
             output_permissions = get_user_execute_permissions(fs_dir)
-            sync_dirs(fs_dir, input_fs_dir, ignore_dot_git=True, update_git=False)
+
+            _execute_git_cmds_and_report(
+                cmds=[
+                    ["git", "add", "."],
+                    ["git", "commit", "-am", msg],
+                ],
+                cwd=fs_dir,
+                msg="git commit failed for rerender",
+            )
+            curr_commit = _execute_git_cmds_and_report(
+                cmds=[["git", "rev-parse", "HEAD"]],
+                cwd=fs_dir,
+                msg="git rev-parse HEAD failed for rerender curr commit",
+                ignore_stderr=True,
+            ).strip()
+            patch = _execute_git_cmds_and_report(
+                cmds=[["git", "diff", prev_commit + ".." + curr_commit]],
+                cwd=fs_dir,
+                msg="git diff failed for rerender",
+                ignore_stderr=True,
+            )
         else:
+            patch = None
             output_permissions = input_permissions
 
-        chmod_plus_rwX(input_fs_dir, recursive=True, skip_on_error=True)
-
-        return {"commit_message": msg, "permissions": output_permissions}
+        return {
+            "commit_message": msg,
+            "patch": patch,
+            "permissions": output_permissions,
+        }
 
 
 def _parse_package_and_feedstock_names():

conda_forge_feedstock_ops/rerender.py

@@ -113,14 +113,23 @@ def rerender_containerized(feedstock_dir, timeout=None):
             mount_dir=tmpdir,
         )
 
-        if data["commit_message"] is not None:
-            sync_dirs(
-                tmp_feedstock_dir,
-                feedstock_dir,
-                ignore_dot_git=True,
-                update_git=True,
+        if data["commit_message"] is not None and data["patch"] is not None:
+            patch_file = os.path.join(
+                tmpdir, f"rerender-diff-{os.path.basename(feedstock_dir)}.patch"
+            )
+            with open(patch_file, "w") as fp:
+                fp.write(data["patch"])
+            subprocess.run(
+                ["git", "apply", "--allow-empty", patch_file],
+                check=True,
+                cwd=feedstock_dir,
             )
             reset_permissions_with_user_execute(feedstock_dir, data["permissions"])
+            subprocess.run(
+                ["git", "add", "."],
+                check=True,
+                cwd=feedstock_dir,
+            )
 
         # When tempfile removes tempdir, it tries to reset permissions on subdirs.
         # This causes a permission error since the subdirs were made by the user