How does one `git log` tagged commits only?

Question

I'd like to `git log` all the tagged commits on the master branch (and none of the untagged commits). Is this possible?

Accepted Answer

The secret trick to this is to realize that `git log` uses the same rules as `git rev-list`. The latter command has a `--tags` flag to look at tags. So, as with the other answers so far, if you're willing to look at all tagged commits, this single command will do it:

```
git log --no-walk --tags
```

(The `--no-walk` prevents this from starting with tags and finding all their parent commits, and the parents' parents, and so on.)

But you asked for "tagged commits on the master branch", which I assume means (in technical terms) "commits that are both pointed to by tags and reachable via the `master` branch". This is substantially harder (`git rev-list` can do set union via `--stdin --no-walk`, but seems to have no way to do set intersection). Here are several methods of finding the right commit-IDs, with various drawbacks:

First make two file lists: "all tagged commits" and "all commits reachable from master":

```
git rev-list --tags --no-walk > /tmp/all-tags
git rev-list master > /tmp/all-master
```

Now just print lines that appear only in both files. The `comm` utility can do this. It's documented to expect the files to be sorted, but in all implementations I have seen, the files merely need to be in the same order, as it were, so this works without pre-sorting:

```
comm -12 /tmp/all-tags /tmp/all-master
```

Drawbacks: needs two temporary files (unless you use the special `bash` syntax that uses `/dev/fd`); might not work without sorting; requires `comm`.

Same idea as before, but use `uniq -d` to produce the list. This really does require sorting, but you can eliminate the temporary files using a pipe:

```
(git rev-list --tags --no-walk; git rev-list master) | sort | uniq -d
```

Drawback: requires sorting. The commits come out in some strange order, not the order you would normally see with `git log`.

Write your own utility that basically does what the `comm` method would do, but invokes `git rev-list` itself (perhaps a script that creates temp files using `mktemp` to make unique names).

Drawback: requires a lot more work. :-)

In all cases, once you have the list of commit-IDs, you just need to pass them to `git log --no-walk`, e.g.:

```
git log --no-walk $(comm -12 /tmp/all-tags /tmp/all-master)
```

How does one `git log` tagged commits only?

Solution

Problem