Index: README.reference =================================================================== --- 5f61aecb06c2f2579bbb5951b1b53e0dedc434eb/README.reference (mode:100644 sha1:8186a561108d3c62625614272bd5e2f7d5826b4b) +++ bc80a76ad52f0cdf28c4e10a2490da3558f5def6/README.reference (mode:100644 sha1:810f4990448fbee57490a945d03a5e8a3eaadec0) @@ -53,7 +53,7 @@ ################################################################ checkout-cache - checkout-cache [-q] [-a] [-f] [--] ... + checkout-cache [-q] [-a] [-f] [--prefix=] [--] ... Will copy all files listed from the cache to the working directory (not overwriting existing files). Note that the file contents are @@ -69,6 +69,13 @@ checks out all files in the cache before processing listed files. +--prefix= + When creating files, prepend this (usually a + directory including a trailing /) + +-- + Do not interpret any more arguments as options. + Note that the order of the flags matters: checkout-cache -a -f file.c @@ -96,6 +103,22 @@ problems (not possible in the above example, but get used to it in scripting!). +The prefix ability basically makes it trivial to use checkout-cache as +a "export as tree" function. Just read the desired tree into the +index, and do a + + checkout-cache --prefix=export-dir/ -a + +and checkout-cache will "export" the cache into the specified +directory. + +NOTE! The final "/" is important. The exported name is literally just +prefixed with the specified string, so you can also do something like + + checkout-cache --prefix=.merged- Makefile + +to check out the currently cached copy of "Makefile" into the file +".merged-Makefile". ################################################################ commit-id @@ -109,12 +132,340 @@ ################################################################ commit-tree - commit-tree [-p ]* < changelog + commit-tree [-p ]* < changelog + +Creates a new commit object based on the provided tree object and +emits the new commit object id on stdout. If no parent is given then +it is considered to be an initial tree. + +A commit object usually has 1 parent (a commit after a change) or up +to 16 parents. More than one parent represents merge of branches that +led to them. + +While a tree represents a particular directory state of a working +directory, a commit represents that state in "time", and explains how +to get there. + +Normally a commit would identify a new "HEAD" state, and while git +doesn't care where you save the note about that state, in practice we +tend to just write the result to the file ".git/HEAD", so that we can +always see what the last committed state was. + +Options + + + An existing tree object + +-p + Each -p indicates a the id of a parent commit object. + + +Commit Information + +A commit encapsulates: + all parent object ids + author name, email and date + committer name and email and the commit time. + +If not provided, commit-tree uses your name, hostname and domain to +provide author and committer info. This can be overridden using the +following environment variables. + AUTHOR_NAME + AUTHOR_EMAIL + AUTHOR_DATE + COMMIT_AUTHOR_NAME + COMMIT_AUTHOR_EMAIL +(nb <,> and '\n's are stripped) + +A commit comment is read from stdin (max 999 chars) + +see also: write-tree ################################################################ +diff-cache + diff-cache [-r] [-z] [--cached] + +Compares the content and mode of the blobs found via a tree object +with the content of the current cache and, optionally ignoring the +stat state of the file on disk. + +(This is basically a special case of diff-tree that works with the +current cache as the first tree.) + + + The id of a tree or commit object to diff against. + +-r + recurse + +-z + /0 line termination on output + +--cached + do not consider the on-disk file at all + +Output format: + +For files in the tree but not in the cache +-\t \t \t + +For files in the cache but not in the tree ++\t \t \t + +For files that differ: +*->\t \t ->\t + +In the special case of the file being changed on disk and out of sync +with the cache, the sha1 is all 0's. Example: + + *100644->100660 blob 5be4a414b32cf4204f889469942986d3d783da84->0000000000000000000000000000000000000000 file.c + + +Operating Modes +You can choose whether you want to trust the index file entirely +(using the "--cached" flag) or ask the diff logic to show any files +that don't match the stat state as being "tentatively changed". Both +of these operations are very useful indeed. + +Cached Mode +If --cached is specified, it allows you to ask: + show me the differences between HEAD and the current index + contents (the ones I'd write with a "write-tree") + +For example, let's say that you have worked on your index file, and are +ready to commit. You want to see eactly _what_ you are going to commit is +without having to write a new tree object and compare it that way, and to +do that, you just do + + diff-cache --cached $(cat .git/HEAD) + +Example: let's say I had renamed "commit.c" to "git-commit.c", and I had +done an "upate-cache" to make that effective in the index file. +"show-diff" wouldn't show anything at all, since the index file matches +my working directory. But doing a diff-cache does: + torvalds@ppc970:~/git> diff-cache --cached $(cat .git/HEAD) + -100644 blob 4161aecc6700a2eb579e842af0b7f22b98443f74 commit.c + +100644 blob 4161aecc6700a2eb579e842af0b7f22b98443f74 git-commit.c + +And as you can see, the output matches "diff-tree -r" output (we +always do "-r", since the index is always fully populated +??CHECK??). +You can trivially see that the above is a rename. + +In fact, "diff-tree --cached" _should_ always be entirely equivalent to +actually doing a "write-tree" and comparing that. Except this one is much +nicer for the case where you just want to check where you are. + +So doing a "diff-cache --cached" is basically very useful when you are +asking yourself "what have I already marked for being committed, and +what's the difference to a previous tree". + +Non-cached Mode + +The "non-cached" mode takes a different approach, and is potentially +the even more useful of the two in that what it does can't be emulated +with a "write-tree + diff-tree". Thus that's the default mode. The +non-cached version asks the question + + "show me the differences between HEAD and the currently checked out + tree - index contents _and_ files that aren't up-to-date" + +which is obviously a very useful question too, since that tells you what +you _could_ commit. Again, the output matches the "diff-tree -r" output to +a tee, but with a twist. + +The twist is that if some file doesn't match the cache, we don't have a +backing store thing for it, and we use the magic "all-zero" sha1 to show +that. So let's say that you have edited "kernel/sched.c", but have not +actually done an update-cache on it yet - there is no "object" associated +with the new state, and you get: + + torvalds@ppc970:~/v2.6/linux> diff-cache $(cat .git/HEAD ) + *100644->100664 blob 7476bbcfe5ef5a1dd87d745f298b831143e4d77e->0000000000000000000000000000000000000000 kernel/sched.c + +ie it shows that the tree has changed, and that "kernel/sched.c" has is +not up-to-date and may contain new stuff. The all-zero sha1 means that to +get the real diff, you need to look at the object in the working directory +directly rather than do an object-to-object diff. + +NOTE! As with other commands of this type, "diff-cache" does not actually +look at the contents of the file at all. So maybe "kernel/sched.c" hasn't +actually changed, and it's just that you touched it. In either case, it's +a note that you need to upate-cache it to make the cache be in sync. + +NOTE 2! You can have a mixture of files show up as "has been updated" and +"is still dirty in the working directory" together. You can always tell +which file is in which state, since the "has been updated" ones show a +valid sha1, and the "not in sync with the index" ones will always have the +special all-zero sha1. + +################################################################ diff-tree - diff-tree [-r] [-z] + diff-tree [-r] [-z] + +Compares the content and mode of the blobs found via two tree objects. + +Note that diff-tree can use the tree encapsulated in a commit object. + + + The id of a tree or commit object. + +-r + recurse + +-z + /0 line termination on output + +--cached + Cached only (private?) + +Output format: + +For files in tree1 but not in tree2 +-\t \t \t + +For files not in tree1 but in tree2 ++\t \t \t + +For files that differ: +*->\t \t ->\t + + +An example of normal usage is: + + torvalds@ppc970:~/git> diff-tree 5319e4d609cdd282069cc4dce33c1db559539b03 b4e628ea30d5ab3606119d2ea5caeab141d38df7 + *100664->100664 blob ac348b7d5278e9d04e3a1cd417389379c32b014f->a01513ed4d4d565911a60981bfb4173311ba3688 fsck-cache.c + +which tells you that the last commit changed just one file (it's from +this one: + + commit 3c6f7ca19ad4043e9e72fa94106f352897e651a8 + tree 5319e4d609cdd282069cc4dce33c1db559539b03 + parent b4e628ea30d5ab3606119d2ea5caeab141d38df7 + author Linus Torvalds Sat Apr 9 12:02:30 2005 + committer Linus Torvalds Sat Apr 9 12:02:30 2005 + + Make "fsck-cache" print out all the root commits it finds. + + Once I do the reference tracking, I'll also make it print out all the + HEAD commits it finds, which is even more interesting. + +in case you care). + + +################################################################ +fsck-cache + fsck-cache [[--unreachable] *] + +Verifies the connectivity and validity of the objects in the database. + + + A commit object to begin an unreachability trace + +--unreachable + print out objects that exist but that aren't readable from any + of the specified root nodes + +It tests SHA1 and general object sanity, but it does full tracking of +the resulting reachability and everything else. It prints out any +corruption it finds (missing or bad objects), and if you use the +"--unreachable" flag it will also print out objects that exist but +that aren't readable from any of the specified root nodes. + +So for example + + fsck-cache --unreachable $(cat .git/HEAD) + +or, for Cogito users: + + fsck-cache --unreachable $(cat .git/heads/*) + +will do quite a _lot_ of verification on the tree. There are a few +extra validity tests to be added (make sure that tree objects are +sorted properly etc), but on the whole if "fsck-cache" is happy, you +do have a valid tree. + +Any corrupt objects you will have to find in backups or other archives +(ie you can just remove them and do an "rsync" with some other site in +the hopes that somebody else has the object you have corrupted). + +Of course, "valid tree" doesn't mean that it wasn't generated by some +evil person, and the end result might be crap. Git is a revision +tracking system, not a quality assurance system ;) + +Extracted Diagnostics +expect dangling commits - potential heads - due to lack of head information + You haven't specified any nodes as heads so it won't be + possible to differentiate between un-parented commits and + root nodes. + +missing sha1 directory '' + The directory holding the sha1 objects is missing. + +unreachable + The object , isn't actually referred to directly + or indirectly in any of the trees or commits seen. This can + mean that there's another root na SHA1_ode that you're not specifying + or that the tree is corrupt. If you haven't missed a root node + then you might as well delete unreachable nodes since they + can't be used. + +missing + The object , is referred to but isn't present in + the database. + +dangling + The object , is present in the database but never + _directly_ used. A dangling commit could be a root node. + +warning: fsck-cache: tree has full pathnames in it + And it shouldn't... + +sha1 mismatch + The database has an object who's sha1 doesn't match the + database value. + This indicates a ??serious?? data integrity problem. + (note: this error occured during early git development when + the database format changed.) + +Environment Variables + +SHA1_FILE_DIRECTORY + used to specify the object database root (usually .git/objects) + +################################################################ +git-export + git-export top [base] + +probably deprecated: +On Wed, 20 Apr 2005, Petr Baudis wrote: +>> I will probably not buy git-export, though. (That is, it is merged, but +>> I won't make git frontend for it.) My "git export" already does +>> something different, but more importantly, "git patch" of mine already +>> does effectively the same thing as you do, just for a single patch; so I +>> will probably just extend it to do it for an (a,b] range of patches. + + +That's fine. It was a quick hack, just to show that if somebody wants to, +the data is trivially exportable. + + Linus + + +################################################################ +init-db + init-db + +This simply creates an empty git object database - basically a .git +directory. + +If the object storage directory is specified via the +SHA1_FILE_DIRECTORY environment variable then the sha1 directories are +created underneath - otherwise the default .git/objects directory is +used. + +init-db won't hurt an existing repository. ################################################################ @@ -134,7 +485,108 @@ ################################################################ read-tree - read-tree [-m] + read-tree ( | -m [ ])" + +Reads the tree information given by into the directory cache, +but does not actually _update_ any of the files it "caches". (see: +checkout-cache) + +Optionally, it can merge a tree into the cache or perform a 3-way +merge. + +Trivial merges are done by read-tree itself. Only conflicting paths +will be in unmerged state when read-tree returns. + + +-m + Perform a merge, not just a read + + + The id of the tree object(s) to be read/merged. + + +Merging +Each "index" entry has two bits worth of "stage" state. stage 0 is the +normal one, and is the only one you'd see in any kind of normal use. + +However, when you do "read-tree" with multiple trees, the "stage" +starts out at 0, but increments for each tree you read. And in +particular, the old "-m" flag (which used to be "merge with old +state") has a new meaning: it now means "start at stage 1" instead. + +This means that you can do + + read-tree -m + +and you will end up with an index with all of the entries in +"stage1", all of the entries in "stage2" and all of the + entries in "stage3". + +Furthermore, "read-tree" has this special-case logic that says: if you +see a file that matches in all respects in all three states, it +"collapses" back to "stage0". + +Write-tree refuses to write a nonsensical tree, so write-tree will +complain about unmerged entries if it sees a single entry that is not +stage 0". + +Ok, this all sounds like a collection of totally nonsensical rules, +but it's actually exactly what you want in order to do a fast +merge. The different stages represent the "result tree" (stage 0, aka +"merged"), the original tree (stage 1, aka "orig"), and the two trees +you are trying to merge (stage 2 and 3 respectively). + +In fact, the way "read-tree" works, it's entirely agnostic about how +you assign the stages, and you could really assign them any which way, +and the above is just a suggested way to do it (except since +"write-tree" refuses to write anything but stage0 entries, it makes +sense to always consider stage 0 to be the "full merge" state). + +So what happens? Try it out. Select the original tree, and two trees +to merge, and look how it works: + + - if a file exists in identical format in all three trees, it will + automatically collapse to "merged" state by the new read-tree. + + - a file that has _any_ difference what-so-ever in the three trees + will stay as separate entries in the index. It's up to "script + policy" to determine how to remove the non-0 stages, and insert a + merged version. But since the index is always sorted, they're easy + to find: they'll be clustered together. + + - the index file saves and restores with all this information, so you + can merge things incrementally, but as long as it has entries in + stages 1/2/3 (ie "unmerged entries") you can't write the result. + +So now the merge algorithm ends up being really simple: + + - you walk the index in order, and ignore all entries of stage 0, + since they've already been done. + + - if you find a "stage1", but no matching "stage2" or "stage3", you + know it's been removed from both trees (it only existed in the + original tree), and you remove that entry. - if you find a + matching "stage2" and "stage3" tree, you remove one of them, and + turn the other into a "stage0" entry. Remove any matching "stage1" + entry if it exists too. .. all the normal trivial rules .. + +NOTE NOTE NOTE! although read-tree coule do some of these nontrivial +merges, only the "matches in all three states" thing collapses by +default. This is because even though there are other trivial cases +("matches in both merge trees but not in the original one"), those +cases might actually be interesting for the merge logic to know about, +so that information is left around. It should be fairly rare anyway, +so a few extra index entries are written out to disk so that the merge +can be annotated. + +Incidentally - it also means that you don't even have to have a separate +subdirectory for this. All the information literally is in the index file, +which is a temporary thing anyway. There is no need to worry about what is in +the working directory, since it is never shown and never used. + +see also: +write-tree +show-files ################################################################ @@ -151,8 +603,145 @@ show-files show-files [-z] [-t] (--[cached|deleted|others|ignored|stage])* +This merges the file listing in the directory cache index with the +actual working directory list, and shows different combinations of the +two. + +--cached + Show cached files in the output (default) + +--deleted + Show deleted files in the output + +--others + Show other files in the output + +--ignored + Show ignored files in the output + +--stage + Show stage files in the output + +-t + Show the following tags (followed by a space) at the start of + each line: + H cached + M unmerged + R removed/deleted + ? other + +-z + /0 line termination on output + +Output +show files just outputs the filename unless --stage is specified in +which case it outputs: + +[ ] + +show-files --unmerged" and "show-files --stage " can be used to examine +detailed information on unmerged paths. + +For an unmerged path, instead of recording a single mode/SHA1 pair, +the dircache records up to three such pairs; one from tree O in stage +1, A in stage 2, and B in stage 3. This information can be used by +the user (or Cogito) to see what should eventually be recorded at the +path. (see read-cache for more information on state) + +see also: +read-cache + ################################################################ unpack-file unpack-file.c +################################################################ +update-cache + update-cache [--add] [--remove] [--refresh] [--cacheinfo ]* [--] []* + +Modifies the index or directory cache. Each file mentioned is updated +into the cache and any 'unmerged' or 'needs updating' state is +cleared. + +The way update-cache handles files it is told about can be modified +using the various options: + +--add + If a specified file isn't in the cache already then it's + added. + Default behaviour is to ignore new files. + +--remove + If a specified file is in the cache but is missing then it's + removed. + Default behaviour is to ignore removed file. + +--refresh + Looks at the current cache and checks to see if merges or + updates are needed by checking stat() information. + +--cacheinfo + Directly insert the specified info into the cache. + +-- + Do not interpret any more arguments as options. + + + Files to act on. + Note that files begining with '.' are discarded. This includes + "./file" and "dir/./file". If you don't want this, then use + cleaner names. + The same applies to directories ending '/' and paths with '//' + + +Using --refresh + +--refresh" does not calculate a new sha1 file or bring the cache +up-to-date for mode/content changes. But what it _does_ do is to +"re-match" the stat information of a file with the cache, so that you +can refresh the cache for a file that hasn't been changed but where +the stat entry is out of date. + +For example, you'd want to do this after doing a "read-tree", to link +up the stat cache details with the proper files. + +Using --cacheinfo +--cacheinfo is used to register a file that is not in the current +working directory. This is useful for minimum-checkout merging. + +To pretend you have a file with mode and sha1 at path, say: + + $ update-cache --cacheinfo mode sha1 path + + +################################################################ +write-tree + write-tree + +Creates a tree object using the current cache. + +The cache must be merged. + +Conceptually, write-tree sync()s the current directory cache contents +into a set of tree files. +In order to have that match what is actually in your directory right +now, you need to have done a "update-cache" phase before you did the +"write-tree". + + +################################################################ + + + +git Environment Variables +AUTHOR_NAME +AUTHOR_EMAIL +AUTHOR_DATE +COMMIT_AUTHOR_NAME +COMMIT_AUTHOR_EMAIL +GIT_DIFF_CMD +GIT_DIFF_OPTS +GIT_INDEX_FILE +SHA1_FILE_DIRECTORY + Index: contrib/gitfeedmaillist.sh ===================================================================