From 5f73076c1a9b4b8dc94f77eac98eb558d25e33c0 Mon Sep 17 00:00:00 2001 From: Junio C Hamano Date: Wed, 8 Feb 2006 21:15:24 -0800 Subject: "Assume unchanged" git This adds "assume unchanged" logic, started by this message in the list discussion recently: This is a workaround for filesystems that do not have lstat() that is quick enough for the index mechanism to take advantage of. On the paths marked as "assumed to be unchanged", the user needs to explicitly use update-index to register the object name to be in the next commit. You can use two new options to update-index to set and reset the CE_VALID bit: git-update-index --assume-unchanged path... git-update-index --no-assume-unchanged path... These forms manipulate only the CE_VALID bit; it does not change the object name recorded in the index file. Nor they add a new entry to the index. When the configuration variable "core.ignorestat = true" is set, the index entries are marked with CE_VALID bit automatically after: - update-index to explicitly register the current object name to the index file. - when update-index --refresh finds the path to be up-to-date. - when tools like read-tree -u and apply --index update the working tree file and register the current object name to the index file. The flag is dropped upon read-tree that does not check out the index entry. This happens regardless of the core.ignorestat settings. Index entries marked with CE_VALID bit are assumed to be unchanged most of the time. However, there are cases that CE_VALID bit is ignored for the sake of safety and usability: - while "git-read-tree -m" or git-apply need to make sure that the paths involved in the merge do not have local modifications. This sacrifices performance for safety. - when git-checkout-index -f -q -u -a tries to see if it needs to checkout the paths. Otherwise you can never check anything out ;-). - when git-update-index --really-refresh (a new flag) tries to see if the index entry is up to date. You can start with everything marked as CE_VALID and run this once to drop CE_VALID bit for paths that are modified. Most notably, "update-index --refresh" honours CE_VALID and does not actively stat, so after you modified a file in the working tree, update-index --refresh would not notice until you tell the index about it with "git-update-index path" or "git-update-index --no-assume-unchanged path". This version is not expected to be perfect. I think diff between index and/or tree and working files may need some adjustment, and there probably needs other cases we should automatically unmark paths that are marked to be CE_VALID. But the basics seem to work, and ready to be tested by people who asked for this feature. Signed-off-by: Junio C Hamano diff --git a/apply.c b/apply.c index 2ad47fb..35ae48e 100644 --- a/apply.c +++ b/apply.c @@ -1309,7 +1309,7 @@ static int check_patch(struct patch *patch) return -1; } - changed = ce_match_stat(active_cache[pos], &st); + changed = ce_match_stat(active_cache[pos], &st, 1); if (changed) return error("%s: does not match index", old_name); diff --git a/cache.h b/cache.h index bdbe2d6..cd58fad 100644 --- a/cache.h +++ b/cache.h @@ -91,6 +91,7 @@ struct cache_entry { #define CE_NAMEMASK (0x0fff) #define CE_STAGEMASK (0x3000) #define CE_UPDATE (0x4000) +#define CE_VALID (0x8000) #define CE_STAGESHIFT 12 #define create_ce_flags(len, stage) htons((len) | ((stage) << CE_STAGESHIFT)) @@ -144,8 +145,8 @@ extern int add_cache_entry(struct cache_entry *ce, int option); extern int remove_cache_entry_at(int pos); extern int remove_file_from_cache(const char *path); extern int ce_same_name(struct cache_entry *a, struct cache_entry *b); -extern int ce_match_stat(struct cache_entry *ce, struct stat *st); -extern int ce_modified(struct cache_entry *ce, struct stat *st); +extern int ce_match_stat(struct cache_entry *ce, struct stat *st, int); +extern int ce_modified(struct cache_entry *ce, struct stat *st, int); extern int ce_path_match(const struct cache_entry *ce, const char **pathspec); extern int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type); extern int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object); @@ -161,6 +162,7 @@ extern int commit_index_file(struct cache_file *); extern void rollback_index_file(struct cache_file *); extern int trust_executable_bit; +extern int assume_unchanged; extern int only_use_symrefs; extern int diff_rename_limit_default; extern int shared_repository; diff --git a/checkout-index.c b/checkout-index.c index 53dd8cb..957b4a8 100644 --- a/checkout-index.c +++ b/checkout-index.c @@ -116,6 +116,7 @@ int main(int argc, char **argv) int all = 0; prefix = setup_git_directory(); + git_config(git_default_config); prefix_length = prefix ? strlen(prefix) : 0; if (read_cache() < 0) { diff --git a/config.c b/config.c index 8355224..7dbdce1 100644 --- a/config.c +++ b/config.c @@ -222,6 +222,11 @@ int git_default_config(const char *var, const char *value) return 0; } + if (!strcmp(var, "core.ignorestat")) { + assume_unchanged = git_config_bool(var, value); + return 0; + } + if (!strcmp(var, "core.symrefsonly")) { only_use_symrefs = git_config_bool(var, value); return 0; diff --git a/diff-files.c b/diff-files.c index d24d11c..c96ad35 100644 --- a/diff-files.c +++ b/diff-files.c @@ -191,7 +191,7 @@ int main(int argc, const char **argv) show_file('-', ce); continue; } - changed = ce_match_stat(ce, &st); + changed = ce_match_stat(ce, &st, 0); if (!changed && !diff_options.find_copies_harder) continue; oldmode = ntohl(ce->ce_mode); diff --git a/diff-index.c b/diff-index.c index f8a102e..12a9418 100644 --- a/diff-index.c +++ b/diff-index.c @@ -33,7 +33,7 @@ static int get_stat_data(struct cache_entry *ce, } return -1; } - changed = ce_match_stat(ce, &st); + changed = ce_match_stat(ce, &st, 0); if (changed) { mode = create_ce_mode(st.st_mode); if (!trust_executable_bit && diff --git a/diff.c b/diff.c index ec51e7d..c72064e 100644 --- a/diff.c +++ b/diff.c @@ -311,7 +311,7 @@ static int work_tree_matches(const char *name, const unsigned char *sha1) ce = active_cache[pos]; if ((lstat(name, &st) < 0) || !S_ISREG(st.st_mode) || /* careful! */ - ce_match_stat(ce, &st) || + ce_match_stat(ce, &st, 0) || memcmp(sha1, ce->sha1, 20)) return 0; /* we return 1 only when we can stat, it is a regular file, diff --git a/entry.c b/entry.c index 6c47c3a..8fb99bc 100644 --- a/entry.c +++ b/entry.c @@ -123,7 +123,7 @@ int checkout_entry(struct cache_entry *ce, struct checkout *state) strcpy(path + len, ce->name); if (!lstat(path, &st)) { - unsigned changed = ce_match_stat(ce, &st); + unsigned changed = ce_match_stat(ce, &st, 1); if (!changed) return 0; if (!state->force) { diff --git a/environment.c b/environment.c index 0596fc6..251e53c 100644 --- a/environment.c +++ b/environment.c @@ -12,6 +12,7 @@ char git_default_email[MAX_GITNAME]; char git_default_name[MAX_GITNAME]; int trust_executable_bit = 1; +int assume_unchanged = 0; int only_use_symrefs = 0; int repository_format_version = 0; char git_commit_encoding[MAX_ENCODING_LENGTH] = "utf-8"; diff --git a/read-cache.c b/read-cache.c index c5474d4..efbb1be 100644 --- a/read-cache.c +++ b/read-cache.c @@ -27,6 +27,9 @@ void fill_stat_cache_info(struct cache_entry *ce, struct stat *st) ce->ce_uid = htonl(st->st_uid); ce->ce_gid = htonl(st->st_gid); ce->ce_size = htonl(st->st_size); + + if (assume_unchanged) + ce->ce_flags |= htons(CE_VALID); } static int ce_compare_data(struct cache_entry *ce, struct stat *st) @@ -146,9 +149,18 @@ static int ce_match_stat_basic(struct cache_entry *ce, struct stat *st) return changed; } -int ce_match_stat(struct cache_entry *ce, struct stat *st) +int ce_match_stat(struct cache_entry *ce, struct stat *st, int ignore_valid) { - unsigned int changed = ce_match_stat_basic(ce, st); + unsigned int changed; + + /* + * If it's marked as always valid in the index, it's + * valid whatever the checked-out copy says. + */ + if (!ignore_valid && (ce->ce_flags & htons(CE_VALID))) + return 0; + + changed = ce_match_stat_basic(ce, st); /* * Within 1 second of this sequence: @@ -164,7 +176,7 @@ int ce_match_stat(struct cache_entry *ce, struct stat *st) * effectively mean we can make at most one commit per second, * which is not acceptable. Instead, we check cache entries * whose mtime are the same as the index file timestamp more - * careful than others. + * carefully than others. */ if (!changed && index_file_timestamp && @@ -174,10 +186,10 @@ int ce_match_stat(struct cache_entry *ce, struct stat *st) return changed; } -int ce_modified(struct cache_entry *ce, struct stat *st) +int ce_modified(struct cache_entry *ce, struct stat *st, int really) { int changed, changed_fs; - changed = ce_match_stat(ce, st); + changed = ce_match_stat(ce, st, really); if (!changed) return 0; /* @@ -233,6 +245,11 @@ int cache_name_compare(const char *name1, int flags1, const char *name2, int fla return -1; if (len1 > len2) return 1; + + /* Differences between "assume up-to-date" should not matter. */ + flags1 &= ~CE_VALID; + flags2 &= ~CE_VALID; + if (flags1 < flags2) return -1; if (flags1 > flags2) @@ -430,6 +447,7 @@ int add_cache_entry(struct cache_entry *ce, int option) int ok_to_add = option & ADD_CACHE_OK_TO_ADD; int ok_to_replace = option & ADD_CACHE_OK_TO_REPLACE; int skip_df_check = option & ADD_CACHE_SKIP_DFCHECK; + pos = cache_name_pos(ce->name, ntohs(ce->ce_flags)); /* existing match? Just replace it. */ diff --git a/read-tree.c b/read-tree.c index 5580f15..52f06e3 100644 --- a/read-tree.c +++ b/read-tree.c @@ -349,7 +349,7 @@ static void verify_uptodate(struct cache_entry *ce) return; if (!lstat(ce->name, &st)) { - unsigned changed = ce_match_stat(ce, &st); + unsigned changed = ce_match_stat(ce, &st, 1); if (!changed) return; errno = 0; diff --git a/update-index.c b/update-index.c index afec98d..767fd49 100644 --- a/update-index.c +++ b/update-index.c @@ -23,6 +23,10 @@ static int quiet; /* --refresh needing update is not error */ static int info_only; static int force_remove; static int verbose; +static int mark_valid_only = 0; +#define MARK_VALID 1 +#define UNMARK_VALID 2 + /* Three functions to allow overloaded pointer return; see linux/err.h */ static inline void *ERR_PTR(long error) @@ -53,6 +57,25 @@ static void report(const char *fmt, ...) va_end(vp); } +static int mark_valid(const char *path) +{ + int namelen = strlen(path); + int pos = cache_name_pos(path, namelen); + if (0 <= pos) { + switch (mark_valid_only) { + case MARK_VALID: + active_cache[pos]->ce_flags |= htons(CE_VALID); + break; + case UNMARK_VALID: + active_cache[pos]->ce_flags &= ~htons(CE_VALID); + break; + } + active_cache_changed = 1; + return 0; + } + return -1; +} + static int add_file_to_cache(const char *path) { int size, namelen, option, status; @@ -94,6 +117,7 @@ static int add_file_to_cache(const char *path) ce = xmalloc(size); memset(ce, 0, size); memcpy(ce->name, path, namelen); + ce->ce_flags = htons(namelen); fill_stat_cache_info(ce, &st); ce->ce_mode = create_ce_mode(st.st_mode); @@ -105,7 +129,6 @@ static int add_file_to_cache(const char *path) if (0 <= pos) ce->ce_mode = active_cache[pos]->ce_mode; } - ce->ce_flags = htons(namelen); if (index_path(ce->sha1, path, &st, !info_only)) return -1; @@ -128,7 +151,7 @@ static int add_file_to_cache(const char *path) * For example, you'd want to do this after doing a "git-read-tree", * to link up the stat cache details with the proper files. */ -static struct cache_entry *refresh_entry(struct cache_entry *ce) +static struct cache_entry *refresh_entry(struct cache_entry *ce, int really) { struct stat st; struct cache_entry *updated; @@ -137,21 +160,22 @@ static struct cache_entry *refresh_entry(struct cache_entry *ce) if (lstat(ce->name, &st) < 0) return ERR_PTR(-errno); - changed = ce_match_stat(ce, &st); + changed = ce_match_stat(ce, &st, really); if (!changed) return NULL; - if (ce_modified(ce, &st)) + if (ce_modified(ce, &st, really)) return ERR_PTR(-EINVAL); size = ce_size(ce); updated = xmalloc(size); memcpy(updated, ce, size); fill_stat_cache_info(updated, &st); + return updated; } -static int refresh_cache(void) +static int refresh_cache(int really) { int i; int has_errors = 0; @@ -171,12 +195,19 @@ static int refresh_cache(void) continue; } - new = refresh_entry(ce); + new = refresh_entry(ce, really); if (!new) continue; if (IS_ERR(new)) { if (not_new && PTR_ERR(new) == -ENOENT) continue; + if (really && PTR_ERR(new) == -EINVAL) { + /* If we are doing --really-refresh that + * means the index is not valid anymore. + */ + ce->ce_flags &= ~htons(CE_VALID); + active_cache_changed = 1; + } if (quiet) continue; printf("%s: needs update\n", ce->name); @@ -274,6 +305,8 @@ static int add_cacheinfo(unsigned int mode, const unsigned char *sha1, memcpy(ce->name, path, len); ce->ce_flags = create_ce_flags(len, stage); ce->ce_mode = create_ce_mode(mode); + if (assume_unchanged) + ce->ce_flags |= htons(CE_VALID); option = allow_add ? ADD_CACHE_OK_TO_ADD : 0; option |= allow_replace ? ADD_CACHE_OK_TO_REPLACE : 0; if (add_cache_entry(ce, option)) @@ -317,6 +350,12 @@ static void update_one(const char *path, const char *prefix, int prefix_length) fprintf(stderr, "Ignoring path %s\n", path); return; } + if (mark_valid_only) { + if (mark_valid(p)) + die("Unable to mark file %s", path); + return; + } + if (force_remove) { if (remove_file_from_cache(p)) die("git-update-index: unable to remove %s", path); @@ -467,7 +506,11 @@ int main(int argc, const char **argv) continue; } if (!strcmp(path, "--refresh")) { - has_errors |= refresh_cache(); + has_errors |= refresh_cache(0); + continue; + } + if (!strcmp(path, "--really-refresh")) { + has_errors |= refresh_cache(1); continue; } if (!strcmp(path, "--cacheinfo")) { @@ -493,6 +536,14 @@ int main(int argc, const char **argv) die("git-update-index: %s cannot chmod %s", path, argv[i]); continue; } + if (!strcmp(path, "--assume-unchanged")) { + mark_valid_only = MARK_VALID; + continue; + } + if (!strcmp(path, "--no-assume-unchanged")) { + mark_valid_only = UNMARK_VALID; + continue; + } if (!strcmp(path, "--info-only")) { info_only = 1; continue; diff --git a/write-tree.c b/write-tree.c index f866059..addb5de 100644 --- a/write-tree.c +++ b/write-tree.c @@ -111,7 +111,7 @@ int main(int argc, char **argv) funny = 0; for (i = 0; i < entries; i++) { struct cache_entry *ce = active_cache[i]; - if (ntohs(ce->ce_flags) & ~CE_NAMEMASK) { + if (ce_stage(ce)) { if (10 < ++funny) { fprintf(stderr, "...\n"); break; -- cgit v0.10.2-6-g49f6 From 8b9b0f3af73233595b6b1103ffb30242508a5e47 Mon Sep 17 00:00:00 2001 From: Junio C Hamano Date: Wed, 8 Feb 2006 21:49:47 -0800 Subject: "Assume unchanged" git: do not set CE_VALID with --refresh When working with automatic assume-unchanged mode using core.ignorestat, setting CE_VALID after --refresh makes things more cumbersome to use. Consider this scenario: (1) the working tree is on a filesystem with slow lstat(2). The user sets core.ignorestat = true. (2) "git checkout" to switch to a different branch (or initial checkout) updates all paths and the index starts out with "all clean". (3) The user knows she wants to edit certain paths. She uses update-index --no-assume-unchanged (we could call it --edit; the name is inmaterial) to mark these paths and starts editing. (4) After editing half of the paths marked to be edited, she runs "git status". This runs "update-index --refresh" to reduce the false hits from diff-files. (5) Now the other half of the paths, since she has not changed them, are found to match the index, and CE_VALID is set on them again. For this reason, this commit makes update-index --refresh not to set CE_VALID even after the path without CE_VALID are verified to be up to date. The user still can run --really-refresh to force lstat() to match the index entries to the reality. Signed-off-by: Junio C Hamano diff --git a/update-index.c b/update-index.c index 767fd49..bb73050 100644 --- a/update-index.c +++ b/update-index.c @@ -172,6 +172,15 @@ static struct cache_entry *refresh_entry(struct cache_entry *ce, int really) memcpy(updated, ce, size); fill_stat_cache_info(updated, &st); + /* In this case, if really is not set, we should leave + * CE_VALID bit alone. Otherwise, paths marked with + * --no-assume-unchanged (i.e. things to be edited) will + * reacquire CE_VALID bit automatically, which is not + * really what we want. + */ + if (!really && assume_unchanged && !(ce->ce_flags & htons(CE_VALID))) + updated->ce_flags &= ~htons(CE_VALID); + return updated; } -- cgit v0.10.2-6-g49f6 From 2bcab24080dc97fc628e1b601a195a9a96773fac Mon Sep 17 00:00:00 2001 From: Junio C Hamano Date: Wed, 8 Feb 2006 21:50:18 -0800 Subject: ls-files: debugging aid for CE_VALID changes. This is not really part of the proposed updates for CE_VALID, but with this change, ls-files -t shows CE_VALID paths with lowercase tag letters instead of the usual uppercase. Useful for checking out what is going on. Signed-off-by: Junio C Hamano diff --git a/ls-files.c b/ls-files.c index 6af3b09..3f06ece 100644 --- a/ls-files.c +++ b/ls-files.c @@ -447,6 +447,22 @@ static void show_ce_entry(const char *tag, struct cache_entry *ce) if (pathspec && !match(pathspec, ce->name, len)) return; + if (tag && *tag && (ce->ce_flags & htons(CE_VALID))) { + static char alttag[4]; + memcpy(alttag, tag, 3); + if (isalpha(tag[0])) + alttag[0] = tolower(tag[0]); + else if (tag[0] == '?') + alttag[0] = '!'; + else { + alttag[0] = 'v'; + alttag[1] = tag[0]; + alttag[2] = ' '; + alttag[3] = 0; + } + tag = alttag; + } + if (!show_stage) { fputs(tag, stdout); write_name_quoted("", 0, ce->name + offset, @@ -503,7 +519,7 @@ static void show_files(void) err = lstat(ce->name, &st); if (show_deleted && err) show_ce_entry(tag_removed, ce); - if (show_modified && ce_modified(ce, &st)) + if (show_modified && ce_modified(ce, &st, 0)) show_ce_entry(tag_modified, ce); } } -- cgit v0.10.2-6-g49f6 From b92b2ce94e5673ab3a2fbc9c762b39aaf7d72de5 Mon Sep 17 00:00:00 2001 From: Junio C Hamano Date: Thu, 9 Feb 2006 00:55:17 -0800 Subject: "Assume unchanged" git: --really-refresh fix. The earlier round failed to make --really-refresh to mark up-to-date index entry to valid again due to a trivial thinko. Signed-off-by: Junio C Hamano diff --git a/update-index.c b/update-index.c index bb73050..ce1db38 100644 --- a/update-index.c +++ b/update-index.c @@ -161,8 +161,13 @@ static struct cache_entry *refresh_entry(struct cache_entry *ce, int really) return ERR_PTR(-errno); changed = ce_match_stat(ce, &st, really); - if (!changed) - return NULL; + if (!changed) { + if (really && assume_unchanged && + !(ce->ce_flags & htons(CE_VALID))) + ; /* mark this one VALID again */ + else + return NULL; + } if (ce_modified(ce, &st, really)) return ERR_PTR(-EINVAL); -- cgit v0.10.2-6-g49f6 From 8bb2e03b9d47d87657b67ddfaf712e736cf3db8f Mon Sep 17 00:00:00 2001 From: Junio C Hamano Date: Sun, 12 Feb 2006 01:47:57 -0800 Subject: ls-files: split "show-valid-bit" into a different option. To preserve compatibility with scripts that expect uppercase letters to be shown, do not make '-t' to unconditionally show the valid bit. Introduce '-v' option for that. Signed-off-by: Junio C Hamano diff --git a/ls-files.c b/ls-files.c index 3f06ece..30296fd 100644 --- a/ls-files.c +++ b/ls-files.c @@ -20,6 +20,7 @@ static int show_unmerged = 0; static int show_modified = 0; static int show_killed = 0; static int show_other_directories = 0; +static int show_valid_bit = 0; static int line_terminator = '\n'; static int prefix_len = 0, prefix_offset = 0; @@ -447,7 +448,8 @@ static void show_ce_entry(const char *tag, struct cache_entry *ce) if (pathspec && !match(pathspec, ce->name, len)) return; - if (tag && *tag && (ce->ce_flags & htons(CE_VALID))) { + if (tag && *tag && show_valid_bit && + (ce->ce_flags & htons(CE_VALID))) { static char alttag[4]; memcpy(alttag, tag, 3); if (isalpha(tag[0])) @@ -592,7 +594,7 @@ static void verify_pathspec(void) } static const char ls_files_usage[] = - "git-ls-files [-z] [-t] (--[cached|deleted|others|stage|unmerged|killed|modified])* " + "git-ls-files [-z] [-t] [-v] (--[cached|deleted|others|stage|unmerged|killed|modified])* " "[ --ignored ] [--exclude=] [--exclude-from=] " "[ --exclude-per-directory= ] [--full-name] [--] []*"; @@ -617,13 +619,15 @@ int main(int argc, const char **argv) line_terminator = 0; continue; } - if (!strcmp(arg, "-t")) { + if (!strcmp(arg, "-t") || !strcmp(arg, "-v")) { tag_cached = "H "; tag_unmerged = "M "; tag_removed = "R "; tag_modified = "C "; tag_other = "? "; tag_killed = "K "; + if (arg[1] == 'v') + show_valid_bit = 1; continue; } if (!strcmp(arg, "-c") || !strcmp(arg, "--cached")) { -- cgit v0.10.2-6-g49f6 From f9666adfead47d265a65c7ba6f90d0ebae3e6b21 Mon Sep 17 00:00:00 2001 From: Junio C Hamano Date: Sun, 12 Feb 2006 01:48:47 -0800 Subject: "assume unchanged" git: documentation. This updates documentation to describe the "assume unchanged" behaviour. Signed-off-by: Junio C Hamano diff --git a/Documentation/git-ls-files.txt b/Documentation/git-ls-files.txt index e433407..e5a92f4 100644 --- a/Documentation/git-ls-files.txt +++ b/Documentation/git-ls-files.txt @@ -8,7 +8,8 @@ git-ls-files - Information about files in the index/working directory SYNOPSIS -------- -'git-ls-files' [-z] [-t] +[verse] +'git-ls-files' [-z] [-t] [-v] (--[cached|deleted|others|ignored|stage|unmerged|killed|modified])\* (-[c|d|o|i|s|u|k|m])\* [-x |--exclude=] @@ -82,6 +83,10 @@ OPTIONS K:: to be killed ? other +-v:: + Similar to `-t`, but use lowercase letters for files + that are marked as 'always matching index'. + --full-name:: When run from a subdirectory, the command usually outputs paths relative to the current directory. This diff --git a/Documentation/git-update-index.txt b/Documentation/git-update-index.txt index c74311d..0a1b0ad 100644 --- a/Documentation/git-update-index.txt +++ b/Documentation/git-update-index.txt @@ -8,11 +8,14 @@ git-update-index - Modifies the index or directory cache SYNOPSIS -------- +[verse] 'git-update-index' [--add] [--remove | --force-remove] [--replace] [--refresh [-q] [--unmerged] [--ignore-missing]] [--cacheinfo ]\* [--chmod=(+|-)x] + [--assume-unchanged | --no-assume-unchanged] + [--really-refresh] [--info-only] [--index-info] [-z] [--stdin] [--verbose] @@ -65,6 +68,18 @@ OPTIONS --chmod=(+|-)x:: Set the execute permissions on the updated files. +--assume-unchanged, --no-assume-unchanged:: + When these flags are specified, the object name recorded + for the paths are not updated. Instead, these options + sets and unsets the "assume unchanged" bit for the + paths. When the "assume unchanged" bit is on, git stops + checking the working tree files for possible + modifications, so you need to manually unset the bit to + tell git when you change the working tree file. This is + sometimes helpful when working with a big project on a + filesystem that has very slow lstat(2) system call + (e.g. cifs). + --info-only:: Do not create objects in the object database for all arguments that follow this flag; just insert @@ -193,6 +208,37 @@ $ git ls-files -s ------------ +Using "assume unchanged" bit +---------------------------- + +Many operations in git depend on your filesystem to have an +efficient `lstat(2)` implementation, so that `st_mtime` +information for working tree files can be cheaply checked to see +if the file contents have changed from the version recorded in +the index file. Unfortunately, some filesystems have +inefficient `lstat(2)`. If your filesystem is one of them, you +can set "assume unchanged" bit to paths you have not changed to +cause git not to do this check. Note that setting this bit on a +path does not mean git will check the contents of the file to +see if it has changed -- it makes git to omit any checking and +assume it has *not* changed. When you make changes to working +tree files, you have to explicitly tell git about it by dropping +"assume unchanged" bit, either before or after you modify them. + +In order to set "assume unchanged" bit, use `--assume-unchanged` +option. To unset, use `--no-assume-unchanged`. + +The command looks at `core.ignorestat` configuration variable. When +this is true, paths updated with `git-update-index paths...` and +paths updated with other git commands that update both index and +working tree (e.g. `git-apply --index`, `git-checkout-index -u`, +and `git-read-tree -u`) are automatically marked as "assume +unchanged". Note that "assume unchanged" bit is *not* set if +`git-update-index --refresh` finds the working tree file matches +the index (use `git-update-index --really-refresh` if you want +to mark them as "assume unchanged"). + + Examples -------- To update and refresh only the files already checked out: @@ -201,6 +247,35 @@ To update and refresh only the files already checked out: $ git-checkout-index -n -f -a && git-update-index --ignore-missing --refresh ---------------- +On an inefficient filesystem with `core.ignorestat` set: + +------------ +$ git update-index --really-refresh <1> +$ git update-index --no-assume-unchanged foo.c <2> +$ git diff --name-only <3> +$ edit foo.c +$ git diff --name-only <4> +M foo.c +$ git update-index foo.c <5> +$ git diff --name-only <6> +$ edit foo.c +$ git diff --name-only <7> +$ git update-index --no-assume-unchanged foo.c <8> +$ git diff --name-only <9> +M foo.c + +<1> forces lstat(2) to set "assume unchanged" bits for paths + that match index. +<2> mark the path to be edited. +<3> this does lstat(2) and finds index matches the path. +<4> this does lstat(2) and finds index does not match the path. +<5> registering the new version to index sets "assume unchanged" bit. +<6> and it is assumed unchanged. +<7> even after you edit it. +<8> you can tell about the change after the fact. +<9> now it checks with lstat(2) and finds it has been changed. +------------ + Configuration ------------- @@ -213,6 +288,9 @@ in the index and the file mode on the filesystem if they differ only on executable bit. On such an unfortunate filesystem, you may need to use `git-update-index --chmod=`. +The command looks at `core.ignorestat` configuration variable. See +'Using "assume unchanged" bit' section above. + See Also -------- -- cgit v0.10.2-6-g49f6 From 7b80be150ce137a790f498a69a784d61d8fc2e78 Mon Sep 17 00:00:00 2001 From: Junio C Hamano Date: Sun, 12 Feb 2006 23:46:25 -0800 Subject: cache_name_compare() compares name and stage, nothing else. The code was a bit unclear in expressing what it wants to compare. Signed-off-by: Junio C Hamano diff --git a/read-cache.c b/read-cache.c index efbb1be..f97f92d 100644 --- a/read-cache.c +++ b/read-cache.c @@ -246,9 +246,9 @@ int cache_name_compare(const char *name1, int flags1, const char *name2, int fla if (len1 > len2) return 1; - /* Differences between "assume up-to-date" should not matter. */ - flags1 &= ~CE_VALID; - flags2 &= ~CE_VALID; + /* Compare stages */ + flags1 &= CE_STAGEMASK; + flags2 &= CE_STAGEMASK; if (flags1 < flags2) return -1; -- cgit v0.10.2-6-g49f6