git log -p -m: document -m and honor --first-parent
git log -p -m is used to show one merge entry per parent, with an appropriate diff; this can be useful when examining histories where full set of changes introduced by a merged branch is interesting, not only the conflicts. This patch properly documents the -m switch, which has so far been mentioned only as a fairly special diff-tree flag. It also makes the code show full patch entry only for the first parent when --first-parent is used. Thus: git log -p -m --first-parent will show the history from the "main branch perspective", while also including full diff of changes introduced by other merged in branches. Signed-off-by: Petr Baudis <pasky@suse.cz> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Petr Baudis committed
Feb 10, 2010 at 02:11 UTC
88d9d45d071379e81e585faa95e4f28414d7d973
4 files changed
+32
-3
Documentation/diff-generate-patch.txt
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-1
@@ -56,7 +56,8 @@ combined diff format
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"git-diff-tree", "git-diff-files" and "git-diff" can take '-c' or
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'--cc' option to produce 'combined diff'. For showing a merge commit
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-with "git log -p", this is the default format.
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+with "git log -p", this is the default format; you can force showing
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+full diff with the '-m' option.
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A 'combined diff' format looks like this:
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------------
Documentation/git-log.txt
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@@ -118,6 +118,15 @@ git log master --not --remotes=*/master::
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Shows all commits that are in local master but not in any remote
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repository master branches.
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+git log -p -m --first-parent::
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+
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+ Shows the history including change diffs, but only from the
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+ "main branch" perspective, skipping commits that come from merged
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+ branches, and showing full diffs of changes introduced by the merges.
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+ This makes sense only when following a strict policy of merging all
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+ topic branches when staying on a single integration branch.
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+
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+
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Discussion
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----------
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Documentation/rev-list-options.txt
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@@ -108,8 +108,8 @@ options may be given. See linkgit:git-diff-files[1] for more options.
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-c::
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- This flag changes the way a merge commit is displayed. It shows
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- the differences from each of the parents to the merge result
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+ With this option, diff output for a merge commit
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+ shows the differences from each of the parents to the merge result
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simultaneously instead of showing pairwise diff between a parent
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and the result one at a time. Furthermore, it lists only files
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which were modified from all parents.
@@ -121,6 +121,15 @@ options may be given. See linkgit:git-diff-files[1] for more options.
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the parents have only two variants and the merge result picks
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one of them without modification.
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+-m::
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+
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+ This flag makes the merge commits show the full diff like
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+ regular commits; for each merge parent, a separate log entry
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+ and diff is generated. An exception is that only diff against
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+ the first parent is shown when '--first-parent' option is given;
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+ in that case, the output represents the changes the merge
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+ brought _into_ the then-current branch.
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+
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-r::
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Show recursive diffs.
log-tree.c
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@@ -514,6 +514,16 @@ static int log_tree_diff(struct rev_info *opt, struct commit *commit, struct log
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return 0;
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else if (opt->combine_merges)
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return do_diff_combined(opt, commit);
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+ else if (opt->first_parent_only) {
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+ /*
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+ * Generate merge log entry only for the first
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+ * parent, showing summary diff of the others
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+ * we merged _in_.
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+ */
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+ diff_tree_sha1(parents->item->object.sha1, sha1, "", &opt->diffopt);
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+ log_tree_diff_flush(opt);
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+ return !opt->loginfo;
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+ }
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/* If we show individual diffs, show the parent info */
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log->parent = parents->item;