diff options
Diffstat (limited to 'Documentation/rev-list-options.txt')
| -rw-r--r-- | Documentation/rev-list-options.txt | 203 |
1 files changed, 153 insertions, 50 deletions
diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt index bfd02ade99..b1c8f86c6e 100644 --- a/Documentation/rev-list-options.txt +++ b/Documentation/rev-list-options.txt @@ -128,8 +128,12 @@ parents) and `--max-parents=-1` (negative numbers denote no upper limit). because merges into a topic branch tend to be only about adjusting to updated upstream from time to time, and this option allows you to ignore the individual commits - brought in to your history by such a merge. Cannot be - combined with --bisect. + brought in to your history by such a merge. +ifdef::git-log[] ++ +This option also changes default diff format for merge commits +to `first-parent`, see `--diff-merges=first-parent` for details. +endif::git-log[] --not:: Reverses the meaning of the '{caret}' prefix (or lack thereof) @@ -207,7 +211,7 @@ ifndef::git-rev-list[] Pretend as if the bad bisection ref `refs/bisect/bad` was listed and as if it was followed by `--not` and the good bisection refs `refs/bisect/good-*` on the command - line. Cannot be combined with --first-parent. + line. endif::git-rev-list[] --stdin:: @@ -223,6 +227,15 @@ ifdef::git-rev-list[] test the exit status to see if a range of objects is fully connected (or not). It is faster than redirecting stdout to `/dev/null` as the output does not have to be formatted. + +--disk-usage:: + Suppress normal output; instead, print the sum of the bytes used + for on-disk storage by the selected commits or objects. This is + equivalent to piping the output into `git cat-file + --batch-check='%(objectsize:disk)'`, except that it runs much + faster (especially with `--use-bitmap-index`). See the `CAVEATS` + section in linkgit:git-cat-file[1] for the limitations of what + "on-disk storage" means. endif::git-rev-list[] --cherry-mark:: @@ -342,6 +355,12 @@ Default mode:: branches if the end result is the same (i.e. merging branches with the same content) +--show-pulls:: + Include all commits from the default mode, but also any merge + commits that are not TREESAME to the first parent but are + TREESAME to a later parent. This mode is helpful for showing + the merge commits that "first introduced" a change to a branch. + --full-history:: Same as the default mode, but does not prune some history. @@ -534,7 +553,7 @@ Note the major differences in `N`, `P`, and `Q` over `--full-history`: parent and is TREESAME. -- -Finally, there is a fifth simplification mode available: +There is another simplification mode available: --ancestry-path:: Limit the displayed commits to those directly on the ancestry @@ -573,6 +592,135 @@ option does. Applied to the 'D..M' range, it results in: L--M ----------------------------------------------------------------------- +Before discussing another option, `--show-pulls`, we need to +create a new example history. + +A common problem users face when looking at simplified history is that a +commit they know changed a file somehow does not appear in the file's +simplified history. Let's demonstrate a new example and show how options +such as `--full-history` and `--simplify-merges` works in that case: + +----------------------------------------------------------------------- + .-A---M-----C--N---O---P + / / \ \ \/ / / + I B \ R-'`-Z' / + \ / \/ / + \ / /\ / + `---X--' `---Y--' +----------------------------------------------------------------------- + +For this example, suppose `I` created `file.txt` which was modified by +`A`, `B`, and `X` in different ways. The single-parent commits `C`, `Z`, +and `Y` do not change `file.txt`. The merge commit `M` was created by +resolving the merge conflict to include both changes from `A` and `B` +and hence is not TREESAME to either. The merge commit `R`, however, was +created by ignoring the contents of `file.txt` at `M` and taking only +the contents of `file.txt` at `X`. Hence, `R` is TREESAME to `X` but not +`M`. Finally, the natural merge resolution to create `N` is to take the +contents of `file.txt` at `R`, so `N` is TREESAME to `R` but not `C`. +The merge commits `O` and `P` are TREESAME to their first parents, but +not to their second parents, `Z` and `Y` respectively. + +When using the default mode, `N` and `R` both have a TREESAME parent, so +those edges are walked and the others are ignored. The resulting history +graph is: + +----------------------------------------------------------------------- + I---X +----------------------------------------------------------------------- + +When using `--full-history`, Git walks every edge. This will discover +the commits `A` and `B` and the merge `M`, but also will reveal the +merge commits `O` and `P`. With parent rewriting, the resulting graph is: + +----------------------------------------------------------------------- + .-A---M--------N---O---P + / / \ \ \/ / / + I B \ R-'`--' / + \ / \/ / + \ / /\ / + `---X--' `------' +----------------------------------------------------------------------- + +Here, the merge commits `O` and `P` contribute extra noise, as they did +not actually contribute a change to `file.txt`. They only merged a topic +that was based on an older version of `file.txt`. This is a common +issue in repositories using a workflow where many contributors work in +parallel and merge their topic branches along a single trunk: manu +unrelated merges appear in the `--full-history` results. + +When using the `--simplify-merges` option, the commits `O` and `P` +disappear from the results. This is because the rewritten second parents +of `O` and `P` are reachable from their first parents. Those edges are +removed and then the commits look like single-parent commits that are +TREESAME to their parent. This also happens to the commit `N`, resulting +in a history view as follows: + +----------------------------------------------------------------------- + .-A---M--. + / / \ + I B R + \ / / + \ / / + `---X--' +----------------------------------------------------------------------- + +In this view, we see all of the important single-parent changes from +`A`, `B`, and `X`. We also see the carefully-resolved merge `M` and the +not-so-carefully-resolved merge `R`. This is usually enough information +to determine why the commits `A` and `B` "disappeared" from history in +the default view. However, there are a few issues with this approach. + +The first issue is performance. Unlike any previous option, the +`--simplify-merges` option requires walking the entire commit history +before returning a single result. This can make the option difficult to +use for very large repositories. + +The second issue is one of auditing. When many contributors are working +on the same repository, it is important which merge commits introduced +a change into an important branch. The problematic merge `R` above is +not likely to be the merge commit that was used to merge into an +important branch. Instead, the merge `N` was used to merge `R` and `X` +into the important branch. This commit may have information about why +the change `X` came to override the changes from `A` and `B` in its +commit message. + +--show-pulls:: + In addition to the commits shown in the default history, show + each merge commit that is not TREESAME to its first parent but + is TREESAME to a later parent. ++ +When a merge commit is included by `--show-pulls`, the merge is +treated as if it "pulled" the change from another branch. When using +`--show-pulls` on this example (and no other options) the resulting +graph is: ++ +----------------------------------------------------------------------- + I---X---R---N +----------------------------------------------------------------------- ++ +Here, the merge commits `R` and `N` are included because they pulled +the commits `X` and `R` into the base branch, respectively. These +merges are the reason the commits `A` and `B` do not appear in the +default history. ++ +When `--show-pulls` is paired with `--simplify-merges`, the +graph includes all of the necessary information: ++ +----------------------------------------------------------------------- + .-A---M--. N + / / \ / + I B R + \ / / + \ / / + `---X--' +----------------------------------------------------------------------- ++ +Notice that since `M` is reachable from `R`, the edge from `N` to `M` +was simplified away. However, `N` still appears in the history as an +important commit because it "pulled" the change `R` into the main +branch. + The `--simplify-by-decoration` option allows you to view only the big picture of the topology of the history, by omitting commits that are not referenced by tags. Commits are marked as !TREESAME @@ -608,7 +756,7 @@ outputs 'midpoint', the output of the two commands would be of roughly the same length. Finding the change which introduces a regression is thus reduced to a binary search: repeatedly generate and test new 'midpoint's until the commit chain is of length -one. Cannot be combined with --first-parent. +one. --bisect-vars:: This calculates the same as `--bisect`, except that refs in @@ -982,48 +1130,3 @@ ifdef::git-rev-list[] by a tab. endif::git-rev-list[] endif::git-shortlog[] - -ifndef::git-shortlog[] -ifndef::git-rev-list[] -Diff Formatting -~~~~~~~~~~~~~~~ - -Listed below are options that control the formatting of diff output. -Some of them are specific to linkgit:git-rev-list[1], however other diff -options may be given. See linkgit:git-diff-files[1] for more options. - --c:: - With this option, diff output for a merge commit - shows the differences from each of the parents to the merge result - simultaneously instead of showing pairwise diff between a parent - and the result one at a time. Furthermore, it lists only files - which were modified from all parents. - ---cc:: - This flag implies the `-c` option and further compresses the - patch output by omitting uninteresting hunks whose contents in - the parents have only two variants and the merge result picks - one of them without modification. - ---combined-all-paths:: - This flag causes combined diffs (used for merge commits) to - list the name of the file from all parents. It thus only has - effect when -c or --cc are specified, and is likely only - useful if filename changes are detected (i.e. when either - rename or copy detection have been requested). - --m:: - This flag makes the merge commits show the full diff like - regular commits; for each merge parent, a separate log entry - and diff is generated. An exception is that only diff against - the first parent is shown when `--first-parent` option is given; - in that case, the output represents the changes the merge - brought _into_ the then-current branch. - --r:: - Show recursive diffs. - --t:: - Show the tree objects in the diff output. This implies `-r`. -endif::git-rev-list[] -endif::git-shortlog[] |