Explain ADD invalidation more accurately
And also move it in to the `ADD` section, rather than being hidden in the `RUN` section.
Docker-DCO-1.1-Signed-off-by: Daniel Watkins (github: OddBloke)
@@ -169,9 +169,8 @@ will be reused during the next build.
The cache for `RUN` instructions can be invalidated by using the `--no-cache`
flag, for example `docker build --no-cache`.
-The first encountered `ADD` instruction will invalidate the cache for all
-following instructions from the 'Dockerfile' if the contents of the context
-have changed. This will also invalidate the cache for `RUN` instructions.
+The cache for `RUN` instructions can be invalidated by `ADD` instructions. See
+[below](#add) for details.
### Known Issues (RUN)
@@ -285,6 +284,11 @@ In the case where `<src>` is a remote file URL, the destination will have permis
> or use another tool from within the container as ADD does not support
> authentication.
+> **Note**:
+> The first encountered `ADD` instruction will invalidate the cache for all
+> following instructions from the Dockerfile if the contents of `<src>` have
+> changed. This includes invalidating the cache for `RUN` instructions.
+
The copy obeys the following rules:
- The `<src>` path must be inside the *context* of the build;
