1 00:00:00,270 --> 00:00:01,740 Instructor: Now in the last lesson, 2 00:00:01,740 --> 00:00:03,810 we spoke about some of the more basic variants 3 00:00:03,810 --> 00:00:05,400 of version control. 4 00:00:05,400 --> 00:00:09,450 In this lesson, I wanna talk about branches and branching. 5 00:00:09,450 --> 00:00:11,610 Now let's start off with a simple example. 6 00:00:11,610 --> 00:00:15,090 Say if we had version one and two, 7 00:00:15,090 --> 00:00:19,020 so two commits that were made to our local repository. 8 00:00:19,020 --> 00:00:21,570 And at this point, we realize that 9 00:00:21,570 --> 00:00:23,730 we want to maybe try out something different, 10 00:00:23,730 --> 00:00:25,740 maybe build a new feature 11 00:00:25,740 --> 00:00:29,040 or just to mess around with a new idea or concept. 12 00:00:29,040 --> 00:00:32,189 What we can do is instead of continuing to commit 13 00:00:32,189 --> 00:00:34,740 to the main branch that you see here, 14 00:00:34,740 --> 00:00:37,950 we can also create a side branch. 15 00:00:37,950 --> 00:00:41,790 After the second commit, we create a new branch 16 00:00:41,790 --> 00:00:44,910 and we start committing to this new branch 17 00:00:44,910 --> 00:00:47,160 or this experimental branch. 18 00:00:47,160 --> 00:00:50,400 We add some features and we write some code. 19 00:00:50,400 --> 00:00:54,210 Simultaneously, we can continue working on the main branch, 20 00:00:54,210 --> 00:00:56,910 putting out all those essential updates 21 00:00:56,910 --> 00:01:01,910 or bits of code that are maintaining our main project. 22 00:01:01,950 --> 00:01:05,099 But at the same time, we can continue to update 23 00:01:05,099 --> 00:01:07,590 and work on this experimental branch, 24 00:01:07,590 --> 00:01:10,080 trying things out and committing our experiments 25 00:01:10,080 --> 00:01:11,970 to this experimental branch. 26 00:01:11,970 --> 00:01:16,020 So now we have two branches that are parallel to each other 27 00:01:16,020 --> 00:01:18,750 and they can be developed simultaneously. 28 00:01:18,750 --> 00:01:20,550 If at some point in the future 29 00:01:20,550 --> 00:01:23,970 that we decide that that experiment was really fruitful 30 00:01:23,970 --> 00:01:27,390 and the feature that we built in it was really, really great 31 00:01:27,390 --> 00:01:30,750 and we'd like to merge it back to the main branch 32 00:01:30,750 --> 00:01:32,460 or to the main project, 33 00:01:32,460 --> 00:01:34,770 then that can be done really easily as well 34 00:01:34,770 --> 00:01:37,980 by simply placing a merge request in. 35 00:01:37,980 --> 00:01:40,410 And we can bring all of those changes 36 00:01:40,410 --> 00:01:43,650 that we experimented with, that we messed around with, 37 00:01:43,650 --> 00:01:45,480 back to the main project 38 00:01:45,480 --> 00:01:47,640 and check to see if there's any conflict 39 00:01:47,640 --> 00:01:49,320 with the main branch code. 40 00:01:49,320 --> 00:01:52,020 And if not, or if after a little bit of editing, 41 00:01:52,020 --> 00:01:54,630 then we can bring all of those changes 42 00:01:54,630 --> 00:01:57,273 into the main working branch. 43 00:01:58,260 --> 00:02:00,690 And then we can continue working from here 44 00:02:00,690 --> 00:02:04,770 onto the next commit or we can make more branches. 45 00:02:04,770 --> 00:02:07,020 And very often what you see in practice 46 00:02:07,020 --> 00:02:10,350 is that there'll be multiple branches being worked on 47 00:02:10,350 --> 00:02:13,590 at the same time for any given large project. 48 00:02:13,590 --> 00:02:15,000 And the reason is because 49 00:02:15,000 --> 00:02:17,040 sometimes you're developing new features, 50 00:02:17,040 --> 00:02:19,500 sometimes you are fixing bugs, 51 00:02:19,500 --> 00:02:22,980 and all of these things may break your main project. 52 00:02:22,980 --> 00:02:25,440 So you don't want to do it on the main branch. 53 00:02:25,440 --> 00:02:28,230 You only want to put it on to the main branch 54 00:02:28,230 --> 00:02:31,650 once you know that everything is working fine 55 00:02:31,650 --> 00:02:35,130 and then you can bring your code back to the working copy 56 00:02:35,130 --> 00:02:37,710 ready for shipment and deployment. 57 00:02:37,710 --> 00:02:41,640 Let's take a look at how this would work in reality. 58 00:02:41,640 --> 00:02:46,083 Now let's say we navigate back to our story directory. 59 00:02:47,160 --> 00:02:51,390 And inside here, we've still got our previous three chapters 60 00:02:51,390 --> 00:02:53,370 and they are under version control. 61 00:02:53,370 --> 00:02:55,500 So if we just have a look at git log, 62 00:02:55,500 --> 00:02:59,550 you can see that this is currently the most recent commit 63 00:02:59,550 --> 00:03:02,463 and it's also mirrored in our remote. 64 00:03:03,720 --> 00:03:06,750 Let's try and do this locally first. 65 00:03:06,750 --> 00:03:10,020 If I decided that I want to create a new branch, 66 00:03:10,020 --> 00:03:13,260 you can simply just write git branch 67 00:03:13,260 --> 00:03:16,230 and specify the name of your new branch. 68 00:03:16,230 --> 00:03:20,880 I'm going to add a space related plot to my story 69 00:03:20,880 --> 00:03:25,653 so let's call our branch alien-plot. 70 00:03:27,210 --> 00:03:28,080 Hit Enter. 71 00:03:28,080 --> 00:03:30,600 And now you can check out what branches you have 72 00:03:30,600 --> 00:03:34,530 by just writing git branch without the name. 73 00:03:34,530 --> 00:03:37,950 And you can see that you've got one branch called alien-plot 74 00:03:37,950 --> 00:03:39,270 and another one called main 75 00:03:39,270 --> 00:03:41,940 and the asterisk shows you which branch 76 00:03:41,940 --> 00:03:43,620 you are currently on. 77 00:03:43,620 --> 00:03:45,600 So we're currently on the main branch. 78 00:03:45,600 --> 00:03:48,330 We can switch to the alien-plot 79 00:03:48,330 --> 00:03:53,130 by simply writing git checkout alien-plot. 80 00:03:56,730 --> 00:03:57,900 Okay, as it says, 81 00:03:57,900 --> 00:04:01,680 we have now switched to the branch called alien-plot. 82 00:04:01,680 --> 00:04:03,300 Now it is inside this branch 83 00:04:03,300 --> 00:04:07,830 that I'm going to make some changes to my chapters. 84 00:04:07,830 --> 00:04:12,720 Now I'm gonna make some completely nonsensical modification 85 00:04:12,720 --> 00:04:14,850 to my files. 86 00:04:14,850 --> 00:04:16,769 So let's change chapter one. 87 00:04:16,769 --> 00:04:19,773 Let's change chapter two. 88 00:04:26,640 --> 00:04:28,650 Okay, there we go. 89 00:04:28,650 --> 00:04:31,110 Okay, so we've made some modifications to chapter one, 90 00:04:31,110 --> 00:04:32,040 chapter two 91 00:04:32,040 --> 00:04:34,590 and we've decided to change 92 00:04:34,590 --> 00:04:37,050 some of the pre-existing written text 93 00:04:37,050 --> 00:04:40,983 to integrate a space-themed or alien-themed plot. 94 00:04:42,240 --> 00:04:44,280 Let's go ahead and commit that. 95 00:04:44,280 --> 00:04:46,540 So remember we have to do git add 96 00:04:47,550 --> 00:04:51,480 and then git commit -m 97 00:04:51,480 --> 00:04:56,330 and our message is going to be modify chapter one 98 00:04:59,790 --> 00:05:04,493 and two to have alien theme. 99 00:05:06,570 --> 00:05:11,250 Okay, now hit Enter and we've made our commits. 100 00:05:11,250 --> 00:05:13,650 Now if we do a git log, 101 00:05:13,650 --> 00:05:17,580 we can see that we have two commits made on the main branch 102 00:05:17,580 --> 00:05:22,440 and we have one commit made on the alien-plot branch. 103 00:05:22,440 --> 00:05:26,190 So now let's say that we go back onto our main branch. 104 00:05:26,190 --> 00:05:28,290 Whenever you're confused where you are, 105 00:05:28,290 --> 00:05:30,600 you can always do a git branch to check 106 00:05:30,600 --> 00:05:32,550 and see where the asterisk is 107 00:05:32,550 --> 00:05:35,520 and the asterisk is obviously where you are. 108 00:05:35,520 --> 00:05:39,030 So let's do a git checkout main 109 00:05:39,030 --> 00:05:41,640 to go back to the main branch. 110 00:05:41,640 --> 00:05:44,970 So you can see that our main branch is unchanged 111 00:05:44,970 --> 00:05:47,700 with respect to the space or alien plot 112 00:05:47,700 --> 00:05:48,960 that we did just now. 113 00:05:48,960 --> 00:05:51,330 Nothing has changed over here. 114 00:05:51,330 --> 00:05:54,840 So while on the main branch, I'm going to create a new file. 115 00:05:54,840 --> 00:05:56,677 I'm gonna call it chapter4.txt. 116 00:06:01,200 --> 00:06:05,283 And inside chapter four, let's add something. 117 00:06:09,780 --> 00:06:12,030 Okay and hit Enter and say... 118 00:06:12,030 --> 00:06:13,680 By the way, I have no idea what I'm typing. 119 00:06:13,680 --> 00:06:15,750 I'm now making up and destroying 120 00:06:15,750 --> 00:06:18,810 probably in the process a masterpiece but it's okay. 121 00:06:18,810 --> 00:06:21,390 So we now have a chapter four on our main branch 122 00:06:21,390 --> 00:06:26,103 and I'm gonna go ahead and do a git add and git commit. 123 00:06:27,090 --> 00:06:29,880 Now there's ways of combining add and commit together 124 00:06:29,880 --> 00:06:31,410 in the same command 125 00:06:31,410 --> 00:06:32,730 but I think if you're new to Git, 126 00:06:32,730 --> 00:06:34,920 it's always good to really know in your head 127 00:06:34,920 --> 00:06:36,270 exactly what's going on. 128 00:06:36,270 --> 00:06:39,660 So I recommend actually separating those two bits out. 129 00:06:39,660 --> 00:06:42,870 Let's go ahead and give it a commit message 130 00:06:42,870 --> 00:06:45,123 and chapter four. 131 00:06:46,050 --> 00:06:48,000 Okay, so git log. 132 00:06:48,000 --> 00:06:49,590 Let's see, what have we got? 133 00:06:49,590 --> 00:06:52,020 We are currently only looking at the main branch 134 00:06:52,020 --> 00:06:53,790 and we have three commits. 135 00:06:53,790 --> 00:06:57,480 This is the position of our remote. 136 00:06:57,480 --> 00:07:00,030 So on our GitHub repository, 137 00:07:00,030 --> 00:07:02,910 this was the latest commit that it could see. 138 00:07:02,910 --> 00:07:05,460 But on our local Git repository, 139 00:07:05,460 --> 00:07:07,260 this is in fact the latest commit, 140 00:07:07,260 --> 00:07:10,050 the one that we just made where we added chapter four. 141 00:07:10,050 --> 00:07:12,750 And you can see that if I switch between the branches, 142 00:07:12,750 --> 00:07:17,310 say if I go over to alien-plot branch and hit Enter, 143 00:07:17,310 --> 00:07:20,640 you can see that our local files actually changed 144 00:07:20,640 --> 00:07:22,230 as I switch branches. 145 00:07:22,230 --> 00:07:25,470 Let's just say that I'm quite happy with the changes 146 00:07:25,470 --> 00:07:29,250 that I've made in terms of my alien-plot addition 147 00:07:29,250 --> 00:07:32,400 and I would like to merge these changes 148 00:07:32,400 --> 00:07:33,870 back into my main branch. 149 00:07:33,870 --> 00:07:36,210 So I've done a little bit of experimentation 150 00:07:36,210 --> 00:07:37,560 on a separate branch. 151 00:07:37,560 --> 00:07:39,990 I've, you know, messed with a few things 152 00:07:39,990 --> 00:07:42,150 and I think it was a great experiment 153 00:07:42,150 --> 00:07:46,380 so I'm going to put it back into our main branch. 154 00:07:46,380 --> 00:07:47,580 In order to do that, 155 00:07:47,580 --> 00:07:50,820 what you have to do is go back to the main branch. 156 00:07:50,820 --> 00:07:53,640 So git checkout main 157 00:07:53,640 --> 00:07:55,500 and while we're on the main branch, 158 00:07:55,500 --> 00:07:58,110 we're going to merge the changes 159 00:07:58,110 --> 00:08:00,360 inside the alien-plot branch. 160 00:08:00,360 --> 00:08:03,070 So we use the command git merge 161 00:08:04,080 --> 00:08:07,050 and we're going to specify the branch name 162 00:08:07,050 --> 00:08:09,600 which was alien-plot. 163 00:08:09,600 --> 00:08:10,590 Hit Enter. 164 00:08:10,590 --> 00:08:13,590 And this opens up VIM which is a text editor. 165 00:08:13,590 --> 00:08:16,710 And this allows you to add a merge message if you wish. 166 00:08:16,710 --> 00:08:18,990 And alternatively, as we're gonna do here 167 00:08:18,990 --> 00:08:20,490 which is gonna leave it empty, 168 00:08:20,490 --> 00:08:24,423 and you're gonna write :q! to save and quit. 169 00:08:25,590 --> 00:08:29,940 And you can see now I've actually absorbed those changes 170 00:08:29,940 --> 00:08:31,860 from the alien-plot. 171 00:08:31,860 --> 00:08:36,510 And you can see that because if I do git branch, 172 00:08:36,510 --> 00:08:37,647 I am on the main branch. 173 00:08:37,647 --> 00:08:40,740 The alien-plot branch still exists by the way. 174 00:08:40,740 --> 00:08:42,539 If you have a look at git log, 175 00:08:42,539 --> 00:08:45,750 you can see that I've got some of the previous commits 176 00:08:45,750 --> 00:08:48,630 but I've also got this merge branch alien-plot 177 00:08:48,630 --> 00:08:51,330 which was my most recent commit. 178 00:08:51,330 --> 00:08:56,330 Now at this point, let's do a git push 179 00:08:56,460 --> 00:08:58,560 to our origin domain 180 00:08:58,560 --> 00:09:00,933 and remember to add the -U flag. 181 00:09:02,280 --> 00:09:05,310 That's completed and let's check it out online. 182 00:09:05,310 --> 00:09:07,890 If we go over to our story repository, 183 00:09:07,890 --> 00:09:11,280 you can see that there's now five commits. 184 00:09:11,280 --> 00:09:13,080 We modify chapter one and two, 185 00:09:13,080 --> 00:09:14,580 we added chapter four 186 00:09:14,580 --> 00:09:17,400 and we merge the alien-plot branch. 187 00:09:17,400 --> 00:09:20,550 So if you go into Insights and go to Network. 188 00:09:20,550 --> 00:09:23,850 Now if I zoom in on this network graph, 189 00:09:23,850 --> 00:09:26,520 then you can see this is the process 190 00:09:26,520 --> 00:09:27,990 that we've gone through. 191 00:09:27,990 --> 00:09:31,020 This is the main branch where we did chapter one 192 00:09:31,020 --> 00:09:32,400 and chapter two. 193 00:09:32,400 --> 00:09:34,200 And then at this point 194 00:09:34,200 --> 00:09:36,540 after I created chapter two and three, 195 00:09:36,540 --> 00:09:39,390 I created a new branch. 196 00:09:39,390 --> 00:09:41,640 And while inside this branch, I made a commit 197 00:09:41,640 --> 00:09:43,680 that modified chapter one and two 198 00:09:43,680 --> 00:09:45,720 to have an alien theme. 199 00:09:45,720 --> 00:09:47,580 And then on the main branch, 200 00:09:47,580 --> 00:09:49,680 I continued developing the main branch 201 00:09:49,680 --> 00:09:51,660 adding a chapter four. 202 00:09:51,660 --> 00:09:56,190 But subsequently, I realized that I did a great job 203 00:09:56,190 --> 00:09:59,730 adding alien themes to our storyline 204 00:09:59,730 --> 00:10:04,530 and I decided to merge it back into the main branch. 205 00:10:04,530 --> 00:10:07,380 This is basically a graphical representation 206 00:10:07,380 --> 00:10:09,180 of what's been going on. 207 00:10:09,180 --> 00:10:12,840 So that was us creating a branch and merging it. 208 00:10:12,840 --> 00:10:14,790 Now why don't you go ahead and have a go 209 00:10:14,790 --> 00:10:17,070 and create your own repository 210 00:10:17,070 --> 00:10:19,740 both locally as well as on GitHub 211 00:10:19,740 --> 00:10:23,130 and you know, write a story or write a poem, 212 00:10:23,130 --> 00:10:24,270 anything you like 213 00:10:24,270 --> 00:10:29,270 and check out the amazingness that is branching using Git.