# Accuracy of "git blame -C" - are there configuration options? 2 messages from 2024-03-01 to 2024-03-08. Participants: Baumann, Moritz. Thread: https://gitlist.dev/t/61032 ## Baumann, Moritz, 2024-03-01 07:21 Subject: Accuracy of "git blame -C" - are there configuration options? Message-ID: URL: https://gitlist.dev/e/AS1PR02MB81858FD5DDD15551754AEA74945E2%40AS1PR02MB8185.eurprd02.prod.outlook.com ``` Hi, A colleague recently experimented with "git blame -C" and noticed that the accuracy with which git detects lines moved from other files varies a lot depending on the sizes of the files involved. Example repository: https://github.com/Boddlnagg/git-blame-problem The latest commit on all branches moves some lines from Decl.cpp to line 93 of DeclBase.cpp. "git blame -C" doesn't detect this on main, but on the "works-as-expected" branch, in which the size of Decl.cpp was artificially reduced, it does. Further experiments show that the following work as well: git blame -L 93,95 -C main -- DeclBase.cpp git blame -L 80,108 -C main -- DeclBase.cpp However, with a sufficiently large range, it stops working again: git blame -L 80,109 -C main -- DeclBase.cpp How does the pickaxe search of git blame work under the hood? Are there any configuration options I can use if I want to trade performance for accuracy? Best regards, Moritz Baumann ``` ## Baumann, Moritz, 2024-03-08 13:59 Subject: Re: Accuracy of "git blame -C" - are there configuration options? Message-ID: URL: https://gitlist.dev/e/AS1PR02MB81855C978C6A42E4D6E2DE5C94272%40AS1PR02MB8185.eurprd02.prod.outlook.com In-Reply-To: ``` Maybe I should rephrase the question to clarify what I want to achieve: Is there a way to execute 'git blame -C' for an entire large file at once and get the same accurate results as if 'git blame -C -L' had been called for each line separately? ---   Hi, A colleague recently experimented with "git blame -C" and noticed that the accuracy with which git detects lines moved from other files varies a lot depending on the sizes of the files involved. Example repository: https://github.com/Boddlnagg/git-blame-problem The latest commit on all branches moves some lines from Decl.cpp to line 93 of DeclBase.cpp. "git blame -C" doesn't detect this on main, but on the "works-as-expected" branch, in which the size of Decl.cpp was artificially reduced, it does. Further experiments show that the following work as well: git blame -L 93,95 -C main -- DeclBase.cpp git blame -L 80,108 -C main -- DeclBase.cpp However, with a sufficiently large range, it stops working again: git blame -L 80,109 -C main -- DeclBase.cpp How does the pickaxe search of git blame work under the hood? Are there any configuration options I can use if I want to trade performance for accuracy? Best regards, Moritz Baumann ```