Documentation Source Text

[https://git-scm.org|Git] version control system.
SQLite uses
[https://fossil-scm.org/|Fossil] instead, which is a
version control system that was specifically designed
and written to support SQLite.

<p>
People often wonder sometimes ask why SQLite does not use the
[https://git-scm.org|Git] version control system like everybody
else.
This article attempts to answer that question.  Also,
in <a href="#getthecode">section 3</a>, 
this article provides hints to Git users
about how they can easily access the SQLite source code.

................................................................................
<p>
This article is <u>not</u> advocating that you switch your projects
away from Git.  You can use whatever version control system you want.
If you are perfectly happy with Git, then by all means keep using
Git.  But, if you are wondering if there isn't something better,
then maybe try to understand the perspectives presented below.
Use the insights thus obtained to find or write a different and
better version control system, or to make
improvements to Git.

<h2>Edits</h2>

<p>
This article has been revised multiple times in an attempt
to improve clarity, address concerns and misgivings,
and to fix errors identified on
[https://news.ycombinator.com/item?id=16806114|Hacker News],
[https://www.reddit.com/r/programming/comments/8c2niw/why_sqlite_does_not_use_git/|Reddit]
and
[https://lobste.rs/s/slcntl/why_sqlite_does_not_use_git|Lobsters].
The complete edit history can be seen at
[https://sqlite.org/docsrc/finfo/pages/whynotgit.in].
(Usage hint: Click on any two nodes of the graph in the file history
page linked above to see a diff between the two versions.)


<h1>A Few Reasons Why SQLite Does Not Use Git</h1>

<p>
One could summarize the reason why SQLite does not use Git in
a single sentence:  The lead SQLite developer finds Git to be
unpalatable.  If you like Git and want to use it, that's great.
I would rather use something better.

<p>
The following are a few of the reasons why I do not like Git:

<h2>Git does not provide good situational awareness</h2>

<p>
When I want to see what has been happening on SQLite (or any of
about a dozen other projects that I work on) I visit the
[https://sqlite.org/src/timeline|timeline] and in a single
screen I can see a quick summary of all the latest changes,
................................................................................
Git keeps the complete DAG of the check-in sequence.  But branch
tags are local information that is not synced and not retained
once a branch closes.
This makes review of historical
branches tedious.

<p>
As an example, consider display of a single historical
branch of SQLite as rendered by GitHub and by Fossil:




<ul>
<li><b>GitHub:</b> [https://github.com/sqlite/sqlite/commits/prefer-coroutine-sort-subquery]
<li><b>Fossil:</b> [https://sqlite.org/src/timeline?r=prefer-coroutine-sort-subquery]
</ul>

<p>
................................................................................
<p>
As of 2019-03-20, there is now an 
[https://github.com/sqlite/sqlite|official Git mirror] of the
SQLite sources on GitHub.

<p>The mirror is an incremental export of the 
[https://sqlite.org/src/timeline|canonical Fossil repository] for
SQLite.  A cron-job updates the GitHub repository at 17 minutes after
the hour, ever hour.
This is a one-way, read-only code mirror.  No pull requests or 
changes are accepted via GitHub.  The GitHub repository merely copies
the content from the Fossil repository.  All changes are input via
Fossil.

<p>
The hashes that identify check-ins and files on the Git mirror are

[https://git-scm.org|Git] version control system.
SQLite uses
[https://fossil-scm.org/|Fossil] instead, which is a
version control system that was specifically designed
and written to support SQLite.

<p>
People often wonder why SQLite does not use the
[https://git-scm.org|Git] version control system like everybody
else.
This article attempts to answer that question.  Also,
in <a href="#getthecode">section 3</a>, 
this article provides hints to Git users
about how they can easily access the SQLite source code.

................................................................................
<p>
This article is <u>not</u> advocating that you switch your projects
away from Git.  You can use whatever version control system you want.
If you are perfectly happy with Git, then by all means keep using
Git.  But, if you are wondering if there isn't something better,
then maybe try to understand the perspectives presented below.
Use the insights thus obtained to find or write a different and
better version control system, or to just make
improvements to Git itself.

<h2>Edits</h2>

<p>
This article has been revised multiple times in an attempt
to improve clarity, address concerns and misgivings,
and to fix errors identified on
[https://news.ycombinator.com/item?id=16806114|Hacker News],
[https://www.reddit.com/r/programming/comments/8c2niw/why_sqlite_does_not_use_git/|Reddit]
and
[https://lobste.rs/s/slcntl/why_sqlite_does_not_use_git|Lobsters].
The complete edit history can be seen at
[https://sqlite.org/docsrc/finfo/pages/whynotgit.in].
(Usage hint: Click on any two nodes of the graph for a diff.)



<h1>A Few Reasons Why SQLite Does Not Use Git</h1>










<h2>Git does not provide good situational awareness</h2>

<p>
When I want to see what has been happening on SQLite (or any of
about a dozen other projects that I work on) I visit the
[https://sqlite.org/src/timeline|timeline] and in a single
screen I can see a quick summary of all the latest changes,
................................................................................
Git keeps the complete DAG of the check-in sequence.  But branch
tags are local information that is not synced and not retained
once a branch closes.
This makes review of historical
branches tedious.

<p>
As an example, suppose someone (perhaps a customer) asks you:
"What ever became of that 'prefer-coroutine-sort-subquery' branch
from two years ago?"
You might try to answer the query by consulting the history in
your version control system, thusly:

<ul>
<li><b>GitHub:</b> [https://github.com/sqlite/sqlite/commits/prefer-coroutine-sort-subquery]
<li><b>Fossil:</b> [https://sqlite.org/src/timeline?r=prefer-coroutine-sort-subquery]
</ul>

<p>
................................................................................
<p>
As of 2019-03-20, there is now an 
[https://github.com/sqlite/sqlite|official Git mirror] of the
SQLite sources on GitHub.

<p>The mirror is an incremental export of the 
[https://sqlite.org/src/timeline|canonical Fossil repository] for
SQLite.  A cron-job updates the GitHub repository once an hour.

This is a one-way, read-only code mirror.  No pull requests or 
changes are accepted via GitHub.  The GitHub repository merely copies
the content from the Fossil repository.  All changes are input via
Fossil.

<p>
The hashes that identify check-ins and files on the Git mirror are