Long1Tail · Long1Tail · Jun 8, 2026 · Jun 8, 2026 · Jun 8, 2026 · Jun 8, 2026
diff --git a/submissions/lab2.md b/submissions/lab2.md
@@ -0,0 +1,209 @@
+# Lab 2 submission
+
+## Task 1.
+
+### 1
+
+```
+$ git cat-file -p HEAD   
+tree a0ebc8d78ec5cebe0bd415bf9038265fa72a8af1
+parent e74f9ee679e546b734846cf659a43188e28b395f
+author Long1TaiL <m.shulaev@innopolis.university> 1780906325 +0300
+committer Long1TaiL <m.shulaev@innopolis.university> 1780906325 +0300
+gpgsig -----BEGIN SSH SIGNATURE-----
+ U1NIU0lHAAAAAQAAADMAAAALc3NoLWVkMjU1MTkAAAAgLHMegGfcirLfZ5gTp0dP5aRlNq
+ vT3dfDT0vtJN7xsekAAAADZ2l0AAAAAAAAAAZzaGE1MTIAAABTAAAAC3NzaC1lZDI1NTE5
+ AAAAQOUFCQ6k/mRLpmKWcPwXupIb9EPwLYcnQN/RgKv7jnS925zDEVDbg6zQU9HtRt1n0k
+ jNb/lcQ1hQ9QyY7n/OBQw=
+ -----END SSH SIGNATURE-----
+
+docs(lab2): start submission
+
+Signed-off-by: Long1TaiL <m.shulaev@innopolis.university>
+```
+
+```
+$ git cat-file -p a0ebc8d78ec5cebe0bd415bf9038265fa72a8af1
+040000 tree b77c55b65711d03e8add51a686680252046b672e    .github
+100644 blob 1c0a1e94b7bbdd951f456cda51af6b8484cc3cee    .gitignore
+100644 blob d10c04c6e7e0014f4fe883599c11747c15012d4e    README.md
+040000 tree 7d0898a908e274ea809722844cdbd836f3b1c05a    app
+040000 tree 6db686e340ecdd318fa43375e26254293371942a    labs
+040000 tree 3f11973a71be5915539cb53313149aa319d69cb5    lectures
+040000 tree 015b347aa515248532bc54c11dbbd07748aa9fc5    submissions
+```
+
+```
+$ git cat-file -p b77c55b65711d03e8add51a686680252046b672e
+100644 blob 8c55e7441819834ab88d58c7f453c033dd4c6b11    pull_request_template.md
+```
+
+```
+## Goal
+To submit tasks from lab1
+
+## Changes
+submissions/lab1.md and a pull request template were added
+
+## Testing
+
+QuickNotes runs locally
+git log --show-signature demonstrates verified commits
+main branch requires a verification
+
+## Checklist
+- [x] Title is a clear sentence (≤ 70 chars)
+- [x] Commits are signed (`git log --show-signature`)
+- [x] `submissions/labN.md` updated
+```
+
+### 2
+
+```
+ls -la .git/ 
+итого 56
+drwxr-xr-x  7 long1tail long1tail 4096 июн  8 11:12 .
+drwxr-xr-x  8 long1tail long1tail 4096 июн  8 11:10 ..
+-rw-r--r--  1 long1tail long1tail   88 июн  8 11:12 COMMIT_EDITMSG
+-rw-r--r--  1 long1tail long1tail  575 июн  8 11:08 config
+-rw-r--r--  1 long1tail long1tail   73 июн  5 11:06 description
+-rw-r--r--  1 long1tail long1tail    0 июн  5 11:28 FETCH_HEAD
+-rw-r--r--  1 long1tail long1tail   29 июн  8 11:08 HEAD
+drwxr-xr-x  2 long1tail long1tail 4096 июн  5 11:06 hooks
+-rw-r--r--  1 long1tail long1tail 3307 июн  8 11:12 index
+drwxr-xr-x  2 long1tail long1tail 4096 июн  5 11:06 info
+drwxr-xr-x  3 long1tail long1tail 4096 июн  5 11:06 logs
+drwxr-xr-x 54 long1tail long1tail 4096 июн  8 11:12 objects
+-rw-r--r--  1 long1tail long1tail   41 июн  5 11:40 ORIG_HEAD
+-rw-r--r--  1 long1tail long1tail  112 июн  5 11:06 packed-refs
+drwxr-xr-x  5 long1tail long1tail 4096 июн  5 11:06 refs
+```
+
+This is the core of git. Here is stored history, settings and additional data
+
+```
+cat .git/HEAD
+ref: refs/heads/feature/lab2
+```
+
+This is the HEAD pointer. It points to my current state. Also, as .git/HEAD points not to some hash, it means that I am on some branch
+
+```
+ls .git/refs/heads/ 
+feature  main
+```
+
+This is containment of /heads. Branches are stored here. In my repository there are 3 branches (yet). As "feature/lab1" and 'feature/lab2" contains in naming '/' symbol, git creates directory "feature", were 'lab1' and 'lab2' stored. It can be checked by running `ls .git/refs/heads/feature`
+
+```
+ls .git/objects/ | head
+01
+09
+0c
+0e
+15
+17
+1a
+1b
+1c
+1d
+```
+
+In these directories commits are stored. each directory named after first 2 bytes of SHA-hash of commits, stored in them. e.g: in directory ab would be stored abcd.... and abde.... commits
+
+```
+find .git/objects -type f | wc -l
+56
+```
+
+This command shows, how many git objects were found
+
+### 3
+
+```
+$ git reflog              
+14e9283 (HEAD -> feature/lab2) HEAD@{0}: reset: moving to 14e9283
+f6508f8 (origin/feature/lab2) HEAD@{1}: reset: moving to f6508f8
+aa8dd05 HEAD@{2}: reset: moving to aa8dd05
+f6508f8 (origin/feature/lab2) HEAD@{3}: reset: moving to f6508f8
+f6508f8 (origin/feature/lab2) HEAD@{4}: reset: moving to HEAD~2
+14e9283 (HEAD -> feature/lab2) HEAD@{5}: commit: wip(lab2): more progress
+aa8dd05 HEAD@{6}: commit: wip(lab2): start
+f6508f8 (origin/feature/lab2) HEAD@{7}: commit: docs(lab2): added 1.1, 1.2 tasks. Commit before execution of task 1.3
+7722946 HEAD@{8}: commit: docs(lab2): start submission
+e74f9ee (origin/main, origin/HEAD, main) HEAD@{9}: checkout: moving from main to feature/lab2
+e74f9ee (origin/main, origin/HEAD, main) HEAD@{10}: commit: docs(lab1): pull request template completed
+82d4bf6 HEAD@{11}: checkout: moving from feature/lab1 to main
+```
+
+```
+$ git reset --hard 14e9283
+Указатель HEAD сейчас на коммите 14e9283 wip(lab2): more progress
+```
+
+If `git gc` (garbage collector) were run before I restore my commits, information, stored in them would be lost and even git reset --hard <SHA> won't help
+
+## Task 2.
+
+Before:
+```
+git log --oneline --graph
+* f6508f8 (HEAD -> feature/lab2) docs(lab2): added 1.1, 1.2 tasks. Commit before execution of task 1.3
+* 7722946 docs(lab2): start submission
+* e74f9ee (tag: v0.1.0-lab2-long1tail, upstream/main, upstream/HEAD) docs(lab1): pull request template completed
+* 82d4bf6 test: unsigned commit (should fail)
+* 492d4ec docs: add PR template
+* 4b3d0b9 docs: add PR template
+* 66bbd4d docs(lab1): align Task 3 GitHub Community engagement with other courses
+```
+
+After:
+```
+git log --oneline --graph
+* c2aa5f9 (HEAD -> feature/lab2, origin/feature/lab2) docs(lab2): added 1.1, 1.2 tasks. Commit before execution of task 1.3
+* a066fde docs(lab2): start submission
+* 29bcd5e (origin/main, origin/HEAD, main) docs: upstream moved while you worked
+* e74f9ee (tag: v0.1.0-lab2-long1tail, upstream/main, upstream/HEAD) docs(lab1): pull request template completed
+* 82d4bf6 test: unsigned commit (should fail)
+* 492d4ec docs: add PR template
+* 4b3d0b9 docs: add PR template
+* 66bbd4d docs(lab1): align Task 3 GitHub Community engagement with other courses
+```
+
+Merge is good for public branches. It saves complex, non-linear history.
+Rebase creates clean, linear history and perfect for private branches
+
+## Bonus task.
+
+### B.3
+
+```
+git bisect log                                                  
+git bisect start
+# status: waiting for both good and bad commits
+# bad: [f0c9243b7c80ebb930a1ce7048a1d65b4c2ac493] docs(app): mention go test invocation
+git bisect bad f0c9243b7c80ebb930a1ce7048a1d65b4c2ac493
+# status: waiting for good commit(s), bad commit known
+# good: [0ec87b808ae6a257a98ecea4a3c8d38a7f2c5ac7] chore(app): document versioning scheme (bisect fixture baseline)
+git bisect good 0ec87b808ae6a257a98ecea4a3c8d38a7f2c5ac7
+# bad: [f285ede8611e55ac0a7d01100891c0cc775e0709] refactor(store): simplify nextID restoration in load()
+git bisect bad f285ede8611e55ac0a7d01100891c0cc775e0709
+# good: [cb89bb9ee2ee5010b166061447eaca3ae0da2378] docs(store): comment the load() decode step
+git bisect good cb89bb9ee2ee5010b166061447eaca3ae0da2378
+# first bad commit: [f285ede8611e55ac0a7d01100891c0cc775e0709] refactor(store): simplify nextID restoration in load()
+```
+
+```
+commit f285ede8611e55ac0a7d01100891c0cc775e0709
+Author: Dmitrii Creed <creeed22@gmail.com>
+Date:   Fri Jun 5 13:36:56 2026 +0400
+
+    refactor(store): simplify nextID restoration in load()
+
+    Signed-off-by: Dmitrii Creed <creeed22@gmail.com>
+
+ app/store.go | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+ ```
+
+ Bisect works as a binary search. It takes good commmit, bad commit, marks commit in the middle between them for check. After check - bisect marks this commit as bad/good and continue. Therefore, it's asymptotic time complexity is O(log_2(N))