From f61329c0eec5e9caf6953aa2709a47e9462e65fa Mon Sep 17 00:00:00 2001
From: Stefan Sperling <stsp@stsp.name>
Date: Mon, 20 Jan 2025 11:03:02 +0000
Subject: [PATCH] skip full content comparison in 'got status' if file sizes
 differ

Speeds up 'got status' in work trees that contain large files which
are modified.

This change exposes bugs in 'got revert' which now manifest as test failures.
One bug where the size recorded in the file index is not updated during
revert, and another where a wrong base commit is recorded in the file
index entry during revert. Fix those bugs, too.

ok jamsek
---
 lib/worktree.c | 34 +++++++++++++++++++++++++---------
 1 file changed, 25 insertions(+), 9 deletions(-)

diff --git a/lib/worktree.c b/lib/worktree.c
index 5fcb85e3..60ed4f12 100644
--- a/lib/worktree.c
+++ b/lib/worktree.c
@@ -1836,8 +1836,22 @@ get_file_status(unsigned char *status, struct stat *sb,
 		goto done;
 	}
 	fd = -1;
+
+	if (staged_status == GOT_STATUS_NO_CHANGE &&
+	    S_ISREG(sb->st_mode) &&
+	    got_fileindex_entry_filetype_get(ie) ==
+	    GOT_FILEIDX_MODE_REGULAR_FILE &&
+	    ie->size != (sb->st_size & 0xffffffff)) {
+		/*
+		 * The size of regular files differs. We can skip the full
+		 * content comparison loop below but still need to check
+		 * for conflict markers.
+		 */
+		*status = GOT_STATUS_MODIFY;
+	}
+
 	hdrlen = got_object_blob_get_hdrlen(blob);
-	for (;;) {
+	while (*status == GOT_STATUS_NO_CHANGE) {
 		const uint8_t *bbuf = got_object_blob_get_read_buf(blob);
 		err = got_object_blob_read_block(&blen, blob);
 		if (err)
@@ -5352,6 +5366,11 @@ revert_file(void *arg, unsigned char status, unsigned char staged_status,
 					goto done;
 				}
 			}
+			err = got_fileindex_entry_update(ie,
+			    a->worktree->root_fd, relpath,
+			    &blob->id, &ie->commit, 0);
+			if (err)
+				goto done;
 		} else {
 			int is_bad_symlink = 0;
 			if (te && S_ISLNK(te->mode)) {
@@ -5369,14 +5388,11 @@ revert_file(void *arg, unsigned char status, unsigned char staged_status,
 			}
 			if (err)
 				goto done;
-			if (status == GOT_STATUS_DELETE ||
-			    status == GOT_STATUS_MODE_CHANGE) {
-				err = got_fileindex_entry_update(ie,
-				    a->worktree->root_fd, relpath,
-				    &blob->id, a->worktree->base_commit_id, 1);
-				if (err)
-					goto done;
-			}
+			err = got_fileindex_entry_update(ie,
+			    a->worktree->root_fd, relpath,
+			    &blob->id, &ie->commit, 0);
+			if (err)
+				goto done;
 			if (is_bad_symlink) {
 				got_fileindex_entry_filetype_set(ie,
 				    GOT_FILEIDX_MODE_BAD_SYMLINK);
-- 
2.11.4.GIT