diff options
| -rw-r--r-- | Documentation/rev-list-options.txt | 153 |
1 files changed, 136 insertions, 17 deletions
diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt index 1d857559ef..0ce3f7fbd9 100644 --- a/Documentation/rev-list-options.txt +++ b/Documentation/rev-list-options.txt @@ -43,11 +43,13 @@ endif::git-rev-list[] --parents:: - Print the parents of the commit. + Print the parents of the commit. Also enables parent + rewriting, see 'History Simplification' below. --children:: - Print the children of the commit. + Print the children of the commit. Also enables parent + rewriting, see 'History Simplification' below. ifdef::git-rev-list[] --timestamp:: @@ -191,14 +193,6 @@ endif::git-rev-list[] Stop when a given path disappears from the tree. ---full-history:: - - Show also parts of history irrelevant to current state of a given - path. This turns off history simplification, which removed merges - which didn't change anything at all at some child. It will still actually - simplify away merges that didn't change anything at all into either - child. - --no-merges:: Do not print commits with more than one parent. @@ -280,18 +274,144 @@ See also linkgit:git-reflog[1]. Output uninteresting commits at the boundary, which are usually not shown. +-- + +History Simplification +~~~~~~~~~~~~~~~~~~~~~~ + +When optional paths are given, 'git-rev-list' simplifies commits with +various strategies, according to the options you have selected. + +Suppose you specified `foo` as the <paths>. We shall call commits +that modify `foo` !TREESAME, and the rest TREESAME. (In a diff +filtered for `foo`, they look different and equal, respectively.) + +In the following, we will always refer to the same example history to +illustrate the differences between simplification settings. We assume +that you are filtering for a file `foo` in this commit graph: +----------------------------------------------------------------------- + .-A---M---N---O---P + / / / / / + I B C D E + \ / / / / + `-------------' +----------------------------------------------------------------------- +The horizontal line of history A--P is taken to be the first parent of +each merge. The commits are: + +* `I` is the initial commit, in which `foo` exists with contents + "asdf", and a file `quux` exists with contents "quux". Initial + commits are compared to an empty tree, so `I` is !TREESAME. + +* In `A`, `foo` contains just "foo". + +* `B` contains the same change as `A`. Its merge `M` is trivial and + hence TREESAME to all parents. + +* `C` does not change `foo`, but its merge `N` changes it to "foobar", + so it is not TREESAME to any parent. + +* `D` sets `foo` to "baz". Its merge `O` combines the strings from + `N` and `D` to "foobarbaz"; i.e., it is not TREESAME to any parent. + +* `E` changes `quux` to "xyzzy", and its merge `P` combines the + strings to "quux xyzzy". Despite appearing interesting, `P` is + TREESAME to all parents. + +'rev-list' walks backwards through history, including or excluding +commits based on whether '\--full-history' and/or parent rewriting +(via '\--parents' or '\--children') are used. The following settings +are available. + +Default mode:: + + Commits are included if they are not TREESAME to any parent + (though this can be changed, see '\--sparse' below). If the + commit was a merge, and it was TREESAME to one parent, follow + only that parent. (Even if there are several TREESAME + parents, follow only one of them.) Otherwise, follow all + parents. ++ +This results in: ++ +----------------------------------------------------------------------- + .-A---N---O + / / + I---------D +----------------------------------------------------------------------- ++ +Note how the rule to only follow the TREESAME parent, if one is +available, removed `B` from consideration entirely. `C` was +considered via `N`, but is TREESAME. Root commits are compared to an +empty tree, so `I` is !TREESAME. ++ +Parent/child relations are only visible with --parents, but that does +not affect the commits selected in default mode, so we have shown the +parent lines. + +--full-history without parent rewriting:: + + This mode differs from the default in one point: always follow + all parents of a merge, even if it is TREESAME to one of them. + Even if more than one side of the merge has commits that are + included, this does not imply that the merge itself is! In + the example, we get ++ +----------------------------------------------------------------------- + I A B N D O +----------------------------------------------------------------------- ++ +`P` and `M` were excluded because they are TREESAME to a parent. `E`, +`C` and `B` were all walked, but only `B` was !TREESAME, so the others +do not appear. ++ +Note that without parent rewriting, it is not really possible to talk +about the parent/child relationships between the commits, so we show +them disconnected. + +--full-history with parent rewriting:: + + Ordinary commits are only included if they are !TREESAME + (though this can be changed, see '\--sparse' below). ++ +Merges are always included. However, their parent list is rewritten: +Along each parent, prune away commits that are not included +themselves. This results in ++ +----------------------------------------------------------------------- + .-A---M---N---O---P + / / / / / + I B / D / + \ / / / / + `-------------' +----------------------------------------------------------------------- ++ +Compare to '\--full-history' without rewriting above. Note that `E` +was pruned away because it is TREESAME, but the parent list of P was +rewritten to contain `E`'s parent `I`. The same happened for `C` and +`N`. Note also that `P` was included despite being TREESAME. + +In addition to the above settings, you can change whether TREESAME +affects inclusion: + --dense:: + + Commits that are walked are included if they are not TREESAME + to any parent. + --sparse:: -When optional paths are given, the default behaviour ('--dense') is to -only output commits that changes at least one of them, and also ignore -merges that do not touch the given paths. + All commits that are walked are included. ++ +Note that without '\--full-history', this still simplifies merges: if +one of the parents is TREESAME, we follow only that one, so the other +sides of the merge are never walked. -Use the '--sparse' flag to makes the command output all eligible commits -(still subject to count and age limitation), but apply merge -simplification nevertheless. ifdef::git-rev-list[] +Bisection Helpers +~~~~~~~~~~~~~~~~~ + --bisect:: Limit output to the one commit object which is roughly halfway between @@ -341,7 +461,6 @@ after all the sorted commit objects, there will be the same text as if `--bisect-vars` had been used alone. endif::git-rev-list[] --- Commit Ordering ~~~~~~~~~~~~~~~ |