Felipe Contreras <felipe.contre...@gmail.com> writes: >> Imagine that your scoreboard originally has three blocks of text >> (i.e. blame_entry) A, B, and C, and the current suspect for A and C >> are the same, while we already know what the final guilty party for >> B is (which may be some descendant of the "suspect"). > > I don't see how that's possible, but whatever.
The tree in your latest commit HEAD has a file with block of text A followed by block of text B followed by block of text C. The latest commit was the one that added B (perhaps new lines were inserted, or perhaps existing contiguous block of text was replaced, there is no difference between these two cases). You start digging the history of this file from HEAD. Your scoreboard begins with a single blame-entry that covers all three segments, with its suspect set to HEAD. Then pass_blame() discovers that top and bottom segments are older than this latest commit, and splits the originally-one blame entry into three blame entries. The first and the third blame entries cover the block A and the block C respectively, and their suspect fields are both set to HEAD^. The second blame entry covers the block B and its suspect does not change (it still is HEAD). Then it returns to the caller. The caller of pass_blame() looks at the scoreboard and finds these three blame entries. The second one's supect is still the original suspect the caller asked pass_blame() to exonerate blames for, and the suspect failed to do so for block B. The final blame for the middle block is now known to be HEAD. After all of the above, the next iteration of while(1) loop begins. That is how you arrive to the "whatever" situation. You have three blame entries, A, B and C, and suspect of A and C are the same, while B has a different suspect. Then in that "next iteration", we pick blame entry for A and decide to see if HEAD^, which is the suspect for A, can be exonerated of blames for _any_ (not just A) blame entry it currently is suspected for. We call pass_blame() and it will find and process both A and C with a single "git diff-tree", attempting to pass blame to HEAD^^ and its ancestors. -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
