Merge branch 'ds/bundle-uri-5'

The bundle-URI subsystem adds support for creation-token heuristics
to help incremental fetches.

* ds/bundle-uri-5:
  bundle-uri: test missing bundles with heuristic
  bundle-uri: store fetch.bundleCreationToken
  fetch: fetch from an external bundle URI
  bundle-uri: drop bundle.flag from design doc
  clone: set fetch.bundleURI if appropriate
  bundle-uri: download in creationToken order
  bundle-uri: parse bundle.<id>.creationToken values
  bundle-uri: parse bundle.heuristic=creationToken
  t5558: add tests for creationToken heuristic
  bundle: verify using check_connected()
  bundle: test unbundling with incomplete history

3 files changed, 35 insertions, 4 deletions

diff --git a/Documentation/config/bundle.txt b/Documentation/config/bundle.txt
index daa21eb674..3faae38685 100644
--- a/Documentation/config/bundle.txt
+++ b/Documentation/config/bundle.txt
@@ -15,6 +15,13 @@ bundle.mode::
 	complete understanding of the bundled information (`all`) or if any one
 	of the listed bundle URIs is sufficient (`any`).
 
+bundle.heuristic::
+	If this string-valued key exists, then the bundle list is designed to
+	work well with incremental `git fetch` commands. The heuristic signals
+	that there are additional keys available for each bundle that help
+	determine which subset of bundles the client should download. The
+	only value currently understood is `creationToken`.
+
 bundle.<id>.*::
 	The `bundle.<id>.*` keys are used to describe a single item in the
 	bundle list, grouped under `<id>` for identification purposes.
diff --git a/Documentation/config/fetch.txt b/Documentation/config/fetch.txt
index cd65d236b4..568f0f75b3 100644
--- a/Documentation/config/fetch.txt
+++ b/Documentation/config/fetch.txt
@@ -96,3 +96,27 @@ fetch.writeCommitGraph::
 	merge and the write may take longer. Having an updated commit-graph
 	file helps performance of many Git commands, including `git merge-base`,
 	`git push -f`, and `git log --graph`. Defaults to false.
+
+fetch.bundleURI::
+	This value stores a URI for downloading Git object data from a bundle
+	URI before performing an incremental fetch from the origin Git server.
+	This is similar to how the `--bundle-uri` option behaves in
+	linkgit:git-clone[1]. `git clone --bundle-uri` will set the
+	`fetch.bundleURI` value if the supplied bundle URI contains a bundle
+	list that is organized for incremental fetches.
++
+If you modify this value and your repository has a `fetch.bundleCreationToken`
+value, then remove that `fetch.bundleCreationToken` value before fetching from
+the new bundle URI.
+
+fetch.bundleCreationToken::
+	When using `fetch.bundleURI` to fetch incrementally from a bundle
+	list that uses the "creationToken" heuristic, this config value
+	stores the maximum `creationToken` value of the downloaded bundles.
+	This value is used to prevent downloading bundles in the future
+	if the advertised `creationToken` is not strictly larger than this
+	value.
++
+The creation token values are chosen by the provider serving the specific
+bundle URI. If you modify the URI at `fetch.bundleURI`, then be sure to
+remove the value for the `fetch.bundleCreationToken` value before fetching.
diff --git a/Documentation/technical/bundle-uri.txt b/Documentation/technical/bundle-uri.txt
index b78d01d9ad..91d3a13e32 100644
--- a/Documentation/technical/bundle-uri.txt
+++ b/Documentation/technical/bundle-uri.txt
@@ -479,14 +479,14 @@ outline for submitting these features:
    (This choice is an opt-in via a config option and a command-line
    option.)
 
-4. Allow the client to understand the `bundle.flag=forFetch` configuration
+4. Allow the client to understand the `bundle.heuristic` configuration key
    and the `bundle.<id>.creationToken` heuristic. When `git clone`
-   discovers a bundle URI with `bundle.flag=forFetch`, it configures the
-   client repository to check that bundle URI during later `git fetch <remote>`
+   discovers a bundle URI with `bundle.heuristic`, it configures the client
+   repository to check that bundle URI during later `git fetch <remote>`
    commands.
 
 5. Allow clients to discover bundle URIs during `git fetch` and configure
-   a bundle URI for later fetches if `bundle.flag=forFetch`.
+   a bundle URI for later fetches if `bundle.heuristic` is set.
 
 6. Implement the "inspect headers" heuristic to reduce data downloads when
    the `bundle.<id>.creationToken` heuristic is not available.