plugin.py/pluginfactory.py: Implementing BST_MIN_VERSION

The BST_MIN_VERSION guards assert that the BuildStream core which
loaded the plugin is compatible with the plugin itself.

This commit adds BST_MIN_VERSION to the base plugin.py with documentation
informing Plugin authors how to set the minimum version, and also adds
the assertions at plugin loading time in pluginfactory.py.

This commit also:

  * Adds the BST_MIN_VERSION specification to all current core plugins
  * Adds the BST_MIN_VERSION specification to plugins used in test cases

18 files changed, 46 insertions, 1 deletions

diff --git a/src/buildstream/plugins/elements/autotools.py b/src/buildstream/plugins/elements/autotools.py
index c4396c5cc..5f5a1b465 100644
--- a/src/buildstream/plugins/elements/autotools.py
+++ b/src/buildstream/plugins/elements/autotools.py
@@ -60,6 +60,10 @@ from buildstream import BuildElement, SandboxFlags
 
 # Element implementation for the 'autotools' kind.
 class AutotoolsElement(BuildElement):
+    # pylint: disable=attribute-defined-outside-init
+
+    BST_MIN_VERSION = "2.0"
+
     # Enable command batching across prepare() and assemble()
     def configure_sandbox(self, sandbox):
         super().configure_sandbox(sandbox)
diff --git a/src/buildstream/plugins/elements/compose.py b/src/buildstream/plugins/elements/compose.py
index 6e4aed193..9c136df9d 100644
--- a/src/buildstream/plugins/elements/compose.py
+++ b/src/buildstream/plugins/elements/compose.py
@@ -41,6 +41,8 @@ from buildstream import Element, Scope
 class ComposeElement(Element):
     # pylint: disable=attribute-defined-outside-init
 
+    BST_MIN_VERSION = "2.0"
+
     # The compose element's output is its dependencies, so
     # we must rebuild if the dependencies change even when
     # not in strict build plans.
diff --git a/src/buildstream/plugins/elements/filter.py b/src/buildstream/plugins/elements/filter.py
index 37b205fe2..62c04e027 100644
--- a/src/buildstream/plugins/elements/filter.py
+++ b/src/buildstream/plugins/elements/filter.py
@@ -140,6 +140,8 @@ from buildstream import Element, ElementError, Scope
 class FilterElement(Element):
     # pylint: disable=attribute-defined-outside-init
 
+    BST_MIN_VERSION = "2.0"
+
     BST_ARTIFACT_VERSION = 1
 
     # The filter element's output is its dependencies, so
diff --git a/src/buildstream/plugins/elements/import.py b/src/buildstream/plugins/elements/import.py
index 2bbd11354..d9961aa6f 100644
--- a/src/buildstream/plugins/elements/import.py
+++ b/src/buildstream/plugins/elements/import.py
@@ -38,6 +38,8 @@ from buildstream import Element, ElementError
 class ImportElement(Element):
     # pylint: disable=attribute-defined-outside-init
 
+    BST_MIN_VERSION = "2.0"
+
     # Import elements do not run any commands
     BST_RUN_COMMANDS = False
 
diff --git a/src/buildstream/plugins/elements/junction.py b/src/buildstream/plugins/elements/junction.py
index 46c4ddf68..917482d63 100644
--- a/src/buildstream/plugins/elements/junction.py
+++ b/src/buildstream/plugins/elements/junction.py
@@ -165,6 +165,8 @@ from buildstream._pipeline import PipelineError
 class JunctionElement(Element):
     # pylint: disable=attribute-defined-outside-init
 
+    BST_MIN_VERSION = "2.0"
+
     # Junctions are not allowed any dependencies
     BST_FORBID_BDEPENDS = True
     BST_FORBID_RDEPENDS = True
diff --git a/src/buildstream/plugins/elements/manual.py b/src/buildstream/plugins/elements/manual.py
index c95b8e5a2..125c5142b 100644
--- a/src/buildstream/plugins/elements/manual.py
+++ b/src/buildstream/plugins/elements/manual.py
@@ -36,6 +36,10 @@ from buildstream import BuildElement, SandboxFlags
 
 # Element implementation for the 'manual' kind.
 class ManualElement(BuildElement):
+    # pylint: disable=attribute-defined-outside-init
+
+    BST_MIN_VERSION = "2.0"
+
     # Enable command batching across prepare() and assemble()
     def configure_sandbox(self, sandbox):
         super().configure_sandbox(sandbox)
diff --git a/src/buildstream/plugins/elements/pip.py b/src/buildstream/plugins/elements/pip.py
index 06e187b69..5f805f460 100644
--- a/src/buildstream/plugins/elements/pip.py
+++ b/src/buildstream/plugins/elements/pip.py
@@ -36,6 +36,10 @@ from buildstream import BuildElement, SandboxFlags
 
 # Element implementation for the 'pip' kind.
 class PipElement(BuildElement):
+    # pylint: disable=attribute-defined-outside-init
+
+    BST_MIN_VERSION = "2.0"
+
     # Enable command batching across prepare() and assemble()
     def configure_sandbox(self, sandbox):
         super().configure_sandbox(sandbox)
diff --git a/src/buildstream/plugins/elements/script.py b/src/buildstream/plugins/elements/script.py
index e355e5f05..9d780ebe2 100644
--- a/src/buildstream/plugins/elements/script.py
+++ b/src/buildstream/plugins/elements/script.py
@@ -40,6 +40,10 @@ import buildstream
 
 # Element implementation for the 'script' kind.
 class ScriptElement(buildstream.ScriptElement):
+    # pylint: disable=attribute-defined-outside-init
+
+    BST_MIN_VERSION = "2.0"
+
     def configure(self, node):
         for n in node.get_sequence("layout", []):
             dst = self.node_subst_vars(n.get_scalar("destination"))
diff --git a/src/buildstream/plugins/elements/stack.py b/src/buildstream/plugins/elements/stack.py
index df11a257f..b15f67073 100644
--- a/src/buildstream/plugins/elements/stack.py
+++ b/src/buildstream/plugins/elements/stack.py
@@ -29,6 +29,9 @@ from buildstream import Element
 
 # Element implementation for the 'stack' kind.
 class StackElement(Element):
+    # pylint: disable=attribute-defined-outside-init
+
+    BST_MIN_VERSION = "2.0"
 
     # This plugin does not produce any artifacts when built
     BST_ELEMENT_HAS_ARTIFACT = False
diff --git a/src/buildstream/plugins/sources/bzr.py b/src/buildstream/plugins/sources/bzr.py
index 8a02eff95..93b554472 100644
--- a/src/buildstream/plugins/sources/bzr.py
+++ b/src/buildstream/plugins/sources/bzr.py
@@ -66,6 +66,8 @@ from buildstream import utils
 class BzrSource(Source):
     # pylint: disable=attribute-defined-outside-init
 
+    BST_MIN_VERSION = "2.0"
+
     def configure(self, node):
         node.validate_keys(["url", "track", "ref", *Source.COMMON_CONFIG_KEYS])
 
diff --git a/src/buildstream/plugins/sources/git.py b/src/buildstream/plugins/sources/git.py
index 473166132..6427d4b04 100644
--- a/src/buildstream/plugins/sources/git.py
+++ b/src/buildstream/plugins/sources/git.py
@@ -156,7 +156,8 @@ from buildstream import _GitSourceBase
 
 
 class GitSource(_GitSourceBase):
-    pass
+
+    BST_MIN_VERSION = "2.0"
 
 
 # Plugin entry point
diff --git a/src/buildstream/plugins/sources/local.py b/src/buildstream/plugins/sources/local.py
index 57bcf14df..c39e09417 100644
--- a/src/buildstream/plugins/sources/local.py
+++ b/src/buildstream/plugins/sources/local.py
@@ -44,6 +44,8 @@ from buildstream import Source, SourceError
 class LocalSource(Source):
     # pylint: disable=attribute-defined-outside-init
 
+    BST_MIN_VERSION = "2.0"
+
     BST_STAGE_VIRTUAL_DIRECTORY = True
     BST_KEY_REQUIRES_STAGE = True
 
diff --git a/src/buildstream/plugins/sources/patch.py b/src/buildstream/plugins/sources/patch.py
index f33dfedec..18672df8a 100644
--- a/src/buildstream/plugins/sources/patch.py
+++ b/src/buildstream/plugins/sources/patch.py
@@ -52,6 +52,8 @@ from buildstream import utils
 class PatchSource(Source):
     # pylint: disable=attribute-defined-outside-init
 
+    BST_MIN_VERSION = "2.0"
+
     BST_REQUIRES_PREVIOUS_SOURCES_STAGE = True
 
     def configure(self, node):
diff --git a/src/buildstream/plugins/sources/pip.py b/src/buildstream/plugins/sources/pip.py
index 69c08e81f..c0885ce5a 100644
--- a/src/buildstream/plugins/sources/pip.py
+++ b/src/buildstream/plugins/sources/pip.py
@@ -98,6 +98,8 @@ _SDIST_RE = re.compile(r"^([\w.-]+?)-((?:[\d.]+){2,})\.(?:tar|tar.bz2|tar.gz|tar
 class PipSource(Source):
     # pylint: disable=attribute-defined-outside-init
 
+    BST_MIN_VERSION = "2.0"
+
     # We need access to previous sources at track time to use requirements.txt
     # but not at fetch time as self.ref should contain sufficient information
     # for this plugin
diff --git a/src/buildstream/plugins/sources/remote.py b/src/buildstream/plugins/sources/remote.py
index 29333c0d9..57d8743a7 100644
--- a/src/buildstream/plugins/sources/remote.py
+++ b/src/buildstream/plugins/sources/remote.py
@@ -55,6 +55,8 @@ from ._downloadablefilesource import DownloadableFileSource
 class RemoteSource(DownloadableFileSource):
     # pylint: disable=attribute-defined-outside-init
 
+    BST_MIN_VERSION = "2.0"
+
     def configure(self, node):
         super().configure(node)
 
diff --git a/src/buildstream/plugins/sources/tar.py b/src/buildstream/plugins/sources/tar.py
index fc4f5736a..793fd11c9 100644
--- a/src/buildstream/plugins/sources/tar.py
+++ b/src/buildstream/plugins/sources/tar.py
@@ -92,6 +92,8 @@ class ReadableTarInfo(tarfile.TarInfo):
 class TarSource(DownloadableFileSource):
     # pylint: disable=attribute-defined-outside-init
 
+    BST_MIN_VERSION = "2.0"
+
     def configure(self, node):
         super().configure(node)
 
diff --git a/src/buildstream/plugins/sources/workspace.py b/src/buildstream/plugins/sources/workspace.py
index 13e2bb37d..796f2b3d9 100644
--- a/src/buildstream/plugins/sources/workspace.py
+++ b/src/buildstream/plugins/sources/workspace.py
@@ -45,6 +45,9 @@ from buildstream.node import MappingNode
 
 class WorkspaceSource(Source):
     # pylint: disable=attribute-defined-outside-init
+
+    BST_MIN_VERSION = "2.0"
+
     BST_STAGE_VIRTUAL_DIRECTORY = True
     BST_KEY_REQUIRES_STAGE = True
 
diff --git a/src/buildstream/plugins/sources/zip.py b/src/buildstream/plugins/sources/zip.py
index 47823dfde..c112cf10e 100644
--- a/src/buildstream/plugins/sources/zip.py
+++ b/src/buildstream/plugins/sources/zip.py
@@ -69,6 +69,8 @@ from ._downloadablefilesource import DownloadableFileSource
 class ZipSource(DownloadableFileSource):
     # pylint: disable=attribute-defined-outside-init
 
+    BST_MIN_VERSION = "2.0"
+
     def configure(self, node):
         super().configure(node)