Merge branch 'jonathan/workspace-fragment-guess-element' into 'master'

Guess the element when running commands in a workspace

See merge request BuildStream/buildstream!954

11 files changed, 231 insertions, 43 deletions

diff --git a/NEWS b/NEWS
index d11e2c5c4..1212b2f4b 100644
--- a/NEWS
+++ b/NEWS
@@ -86,6 +86,11 @@ buildstream 1.3.1
   o Opening a workspace now creates a .bstproject.yaml file that allows buildstream
     commands to be run from a workspace that is not inside a project.
 
+  o Specifying an element is now optional for some commands when buildstream is run
+    from inside a workspace - the 'build', 'checkout', 'fetch', 'pull', 'push',
+    'shell', 'show', 'source-checkout', 'track', 'workspace close' and 'workspace reset'
+    commands are affected.
+
 
 =================
 buildstream 1.1.5
diff --git a/buildstream/_context.py b/buildstream/_context.py
index 5211fe54d..a3487a794 100644
--- a/buildstream/_context.py
+++ b/buildstream/_context.py
@@ -32,7 +32,7 @@ from ._message import Message, MessageType
 from ._profile import Topics, profile_start, profile_end
 from ._artifactcache import ArtifactCache
 from ._artifactcache.cascache import CASCache
-from ._workspaces import Workspaces, WorkspaceProjectCache
+from ._workspaces import Workspaces, WorkspaceProjectCache, WORKSPACE_PROJECT_FILE
 from .plugin import _plugin_lookup
 
 
@@ -47,9 +47,12 @@ from .plugin import _plugin_lookup
 # verbosity levels and basically anything pertaining to the context
 # in which BuildStream was invoked.
 #
+# Args:
+#    directory (str): The directory that buildstream was invoked in
+#
 class Context():
 
-    def __init__(self):
+    def __init__(self, directory=None):
 
         # Filename indicating which configuration file was used, or None for the defaults
         self.config_origin = None
@@ -148,6 +151,7 @@ class Context():
         self._log_handle = None
         self._log_filename = None
         self._cascache = None
+        self._directory = directory
 
     # load()
     #
@@ -645,6 +649,20 @@ class Context():
             self._cascache = CASCache(self.artifactdir)
         return self._cascache
 
+    # guess_element()
+    #
+    # Attempts to interpret which element the user intended to run commands on
+    #
+    # Returns:
+    #    (str) The name of the element, or None if no element can be guessed
+    def guess_element(self):
+        workspace_project_dir, _ = utils._search_upward_for_files(self._directory, [WORKSPACE_PROJECT_FILE])
+        if workspace_project_dir:
+            workspace_project = self._workspace_project_cache.get(workspace_project_dir)
+            return workspace_project.get_default_element()
+        else:
+            return None
+
 
 # _node_get_option_str()
 #
diff --git a/buildstream/_frontend/app.py b/buildstream/_frontend/app.py
index 4094eec17..87b85cd37 100644
--- a/buildstream/_frontend/app.py
+++ b/buildstream/_frontend/app.py
@@ -164,7 +164,7 @@ class App():
         # Load the Context
         #
         try:
-            self.context = Context()
+            self.context = Context(directory)
             self.context.load(config)
         except BstError as e:
             self._error_exit(e, "Error loading user configuration")
diff --git a/buildstream/_frontend/cli.py b/buildstream/_frontend/cli.py
index e1fab38a0..4900b28a7 100644
--- a/buildstream/_frontend/cli.py
+++ b/buildstream/_frontend/cli.py
@@ -316,10 +316,15 @@ def build(app, elements, all_, track_, track_save, track_all, track_except, trac
     if track_save:
         click.echo("WARNING: --track-save is deprecated, saving is now unconditional", err=True)
 
-    if track_all:
-        track_ = elements
-
     with app.initialized(session_name="Build"):
+        if not all_ and not elements:
+            guessed_target = app.context.guess_element()
+            if guessed_target:
+                elements = (guessed_target,)
+
+        if track_all:
+            track_ = elements
+
         app.stream.build(elements,
                          track_targets=track_,
                          track_except=track_except,
@@ -371,6 +376,11 @@ def fetch(app, elements, deps, track_, except_, track_cross_junctions):
         deps = PipelineSelection.ALL
 
     with app.initialized(session_name="Fetch"):
+        if not elements:
+            guessed_target = app.context.guess_element()
+            if guessed_target:
+                elements = (guessed_target,)
+
         app.stream.fetch(elements,
                          selection=deps,
                          except_targets=except_,
@@ -407,6 +417,11 @@ def track(app, elements, deps, except_, cross_junctions):
         all:   All dependencies of all specified elements
     """
     with app.initialized(session_name="Track"):
+        if not elements:
+            guessed_target = app.context.guess_element()
+            if guessed_target:
+                elements = (guessed_target,)
+
         # Substitute 'none' for 'redirect' so that element redirections
         # will be done
         if deps == 'none':
@@ -442,7 +457,13 @@ def pull(app, elements, deps, remote):
         none:  No dependencies, just the element itself
         all:   All dependencies
     """
+
     with app.initialized(session_name="Pull"):
+        if not elements:
+            guessed_target = app.context.guess_element()
+            if guessed_target:
+                elements = (guessed_target,)
+
         app.stream.pull(elements, selection=deps, remote=remote)
 
 
@@ -475,6 +496,11 @@ def push(app, elements, deps, remote):
         all:   All dependencies
     """
     with app.initialized(session_name="Push"):
+        if not elements:
+            guessed_target = app.context.guess_element()
+            if guessed_target:
+                elements = (guessed_target,)
+
         app.stream.push(elements, selection=deps, remote=remote)
 
 
@@ -545,6 +571,11 @@ def show(app, elements, deps, except_, order, format_):
             $'---------- %{name} ----------\\n%{vars}'
     """
     with app.initialized():
+        if not elements:
+            guessed_target = app.context.guess_element()
+            if guessed_target:
+                elements = (guessed_target,)
+
         dependencies = app.stream.load_selection(elements,
                                                  selection=deps,
                                                  except_targets=except_)
@@ -573,7 +604,7 @@ def show(app, elements, deps, except_, order, format_):
               help="Mount a file or directory into the sandbox")
 @click.option('--isolate', is_flag=True, default=False,
               help='Create an isolated build sandbox')
-@click.argument('element',
+@click.argument('element', required=False,
                 type=click.Path(readable=False))
 @click.argument('command', type=click.STRING, nargs=-1)
 @click.pass_obj
@@ -604,6 +635,11 @@ def shell(app, element, sysroot, mount, isolate, build_, command):
         scope = Scope.RUN
 
     with app.initialized():
+        if not element:
+            element = app.context.guess_element()
+            if not element:
+                raise AppError('Missing argument "ELEMENT".')
+
         dependencies = app.stream.load_selection((element,), selection=PipelineSelection.NONE)
         element = dependencies[0]
         prompt = app.shell_prompt(element)
@@ -641,15 +677,24 @@ def shell(app, element, sysroot, mount, isolate, build_, command):
               help="Create a tarball from the artifact contents instead "
                    "of a file tree. If LOCATION is '-', the tarball "
                    "will be dumped to the standard output.")
-@click.argument('element',
+@click.argument('element', required=False,
                 type=click.Path(readable=False))
-@click.argument('location', type=click.Path())
+@click.argument('location', type=click.Path(), required=False)
 @click.pass_obj
 def checkout(app, element, location, force, deps, integrate, hardlinks, tar):
     """Checkout a built artifact to the specified location
     """
     from ..element import Scope
 
+    if not element and not location:
+        click.echo("ERROR: LOCATION is not specified", err=True)
+        sys.exit(-1)
+
+    if element and not location:
+        # Nasty hack to get around click's optional args
+        location = element
+        element = None
+
     if hardlinks and tar:
         click.echo("ERROR: options --hardlinks and --tar conflict", err=True)
         sys.exit(-1)
@@ -662,6 +707,11 @@ def checkout(app, element, location, force, deps, integrate, hardlinks, tar):
         scope = Scope.NONE
 
     with app.initialized():
+        if not element:
+            element = app.context.guess_element()
+            if not element:
+                raise AppError('Missing argument "ELEMENT".')
+
         app.stream.checkout(element,
                             location=location,
                             force=force,
@@ -683,14 +733,28 @@ def checkout(app, element, location, force, deps, integrate, hardlinks, tar):
               help='The dependencies whose sources to checkout (default: none)')
 @click.option('--fetch', 'fetch_', default=False, is_flag=True,
               help='Fetch elements if they are not fetched')
-@click.argument('element',
+@click.argument('element', required=False,
                 type=click.Path(readable=False))
-@click.argument('location', type=click.Path())
+@click.argument('location', type=click.Path(), required=False)
 @click.pass_obj
 def source_checkout(app, element, location, deps, fetch_, except_):
     """Checkout sources of an element to the specified location
     """
+    if not element and not location:
+        click.echo("ERROR: LOCATION is not specified", err=True)
+        sys.exit(-1)
+
+    if element and not location:
+        # Nasty hack to get around click's optional args
+        location = element
+        element = None
+
     with app.initialized():
+        if not element:
+            element = app.context.guess_element()
+            if not element:
+                raise AppError('Missing argument "ELEMENT".')
+
         app.stream.source_checkout(element,
                                    location=location,
                                    deps=deps,
@@ -747,11 +811,15 @@ def workspace_open(app, no_checkout, force, track_, directory, elements):
 def workspace_close(app, remove_dir, all_, elements):
     """Close a workspace"""
 
-    if not (all_ or elements):
-        click.echo('ERROR: no elements specified', err=True)
-        sys.exit(-1)
-
     with app.initialized():
+        if not (all_ or elements):
+            # NOTE: I may need to revisit this when implementing multiple projects
+            # opening one workspace.
+            element = app.context.guess_element()
+            if element:
+                elements = (element,)
+            else:
+                raise AppError('No elements specified')
 
         # Early exit if we specified `all` and there are no workspaces
         if all_ and not app.stream.workspace_exists():
@@ -808,7 +876,11 @@ def workspace_reset(app, soft, track_, all_, elements):
     with app.initialized():
 
         if not (all_ or elements):
-            raise AppError('No elements specified to reset')
+            element = app.context.guess_element()
+            if element:
+                elements = (element,)
+            else:
+                raise AppError('No elements specified to reset')
 
         if all_ and not app.stream.workspace_exists():
             raise AppError("No open workspaces to reset")
diff --git a/buildstream/_stream.py b/buildstream/_stream.py
index 6d4af1e79..85f77e281 100644
--- a/buildstream/_stream.py
+++ b/buildstream/_stream.py
@@ -544,7 +544,8 @@ class Stream():
             if len(elements) != 1:
                 raise StreamError("Exactly one element can be given if --directory is used",
                                   reason='directory-with-multiple-elements')
-            expanded_directories = [custom_dir, ]
+            directory = os.path.abspath(custom_dir)
+            expanded_directories = [directory, ]
         else:
             # If this fails it is a bug in what ever calls this, usually cli.py and so can not be tested for via the
             # run bst test mechanism.
diff --git a/doc/sessions/developing.run b/doc/sessions/developing.run
index eca2af90b..1ae4eb5ad 100644
--- a/doc/sessions/developing.run
+++ b/doc/sessions/developing.run
@@ -24,6 +24,11 @@ commands:
   output: ../source/sessions/developing-build-after-changes.html
   command: build hello.bst
 
+# Rebuild, from the workspace
+- directory: ../examples/developing/workspace_hello
+  output: ../source/sessions/developing-build-after-changes-workspace.html
+  command: build
+
 # Capture shell output with changes
 - directory: ../examples/developing/
   output: ../source/sessions/developing-shell-after-changes.html
diff --git a/doc/source/developing/workspaces.rst b/doc/source/developing/workspaces.rst
index b5ed64b2c..653716f72 100644
--- a/doc/source/developing/workspaces.rst
+++ b/doc/source/developing/workspaces.rst
@@ -50,11 +50,16 @@ We can open workspace_hello/hello.c and make the following change:
 .. literalinclude:: ../../examples/developing/update.patch
     :language: diff
 
-Now, rebuild the hello.bst element
+Now, rebuild the hello.bst element.
 
 .. raw:: html
    :file: ../sessions/developing-build-after-changes.html
 
+Note that if you run the command from inside the workspace, the element name is optional.
+
+.. raw:: html
+   :file: ../sessions/developing-build-after-changes-workspace.html
+
 Now running the hello command using bst shell:
 
 .. raw:: html
diff --git a/doc/source/sessions-stored/developing-build-after-changes-workspace.html b/doc/source/sessions-stored/developing-build-after-changes-workspace.html
new file mode 100644
index 000000000..54e4ece63
--- /dev/null
+++ b/doc/source/sessions-stored/developing-build-after-changes-workspace.html
@@ -0,0 +1,46 @@
+<!--
+    WARNING: This file was generated with bst2html.py
+-->
+<div class="highlight" style="font-size:x-small"><pre>
+<span style="color:#C4A000;font-weight:bold">user@host</span>:<span style="color:#3456A4;font-weight:bold">~/workspace_hello</span>$ bst build
+
+<span style="color:#06989A"><span style="opacity:0.5">[</span></span><span style="color:#C4A000">--</span><span style="color:#06989A"><span style="opacity:0.5">:</span></span><span style="color:#C4A000">--</span><span style="color:#06989A"><span style="opacity:0.5">:</span></span><span style="color:#C4A000">--</span><span style="color:#06989A"><span style="opacity:0.5">][</span></span><span style="color:#06989A"><span style="opacity:0.5">][</span></span><span style="color:#06989A"><span style="opacity:0.5">] </span></span><span style="color:#3465A4"><span style=""><span style="opacity:0.5">START  </span></span></span><span style="color:#06989A"><span style="opacity:0.5"> </span></span>Build
+<span style="color:#06989A"><span style="opacity:0.5">[</span></span><span style="color:#C4A000">--</span><span style="color:#06989A"><span style="opacity:0.5">:</span></span><span style="color:#C4A000">--</span><span style="color:#06989A"><span style="opacity:0.5">:</span></span><span style="color:#C4A000">--</span><span style="color:#06989A"><span style="opacity:0.5">][</span></span><span style="color:#06989A"><span style="opacity:0.5">][</span></span><span style="color:#06989A"><span style="opacity:0.5">] </span></span><span style="color:#3465A4"><span style=""><span style="opacity:0.5">START  </span></span></span><span style="color:#06989A"><span style="opacity:0.5"> </span></span>Loading elements
+<span style="color:#06989A"><span style="opacity:0.5">[</span></span><span style="color:#C4A000">00</span><span style="color:#06989A"><span style="opacity:0.5">:</span></span><span style="color:#C4A000">00</span><span style="color:#06989A"><span style="opacity:0.5">:</span></span><span style="color:#C4A000">00</span><span style="color:#06989A"><span style="opacity:0.5">][</span></span><span style="color:#06989A"><span style="opacity:0.5">][</span></span><span style="color:#06989A"><span style="opacity:0.5">] </span></span><span style="color:#4E9A06"><span style=""><span style="opacity:0.5">SUCCESS</span></span></span><span style="color:#06989A"><span style="opacity:0.5"> </span></span>Loading elements
+<span style="color:#06989A"><span style="opacity:0.5">[</span></span><span style="color:#C4A000">--</span><span style="color:#06989A"><span style="opacity:0.5">:</span></span><span style="color:#C4A000">--</span><span style="color:#06989A"><span style="opacity:0.5">:</span></span><span style="color:#C4A000">--</span><span style="color:#06989A"><span style="opacity:0.5">][</span></span><span style="color:#06989A"><span style="opacity:0.5">][</span></span><span style="color:#06989A"><span style="opacity:0.5">] </span></span><span style="color:#3465A4"><span style=""><span style="opacity:0.5">START  </span></span></span><span style="color:#06989A"><span style="opacity:0.5"> </span></span>Resolving elements
+<span style="color:#06989A"><span style="opacity:0.5">[</span></span><span style="color:#C4A000">00</span><span style="color:#06989A"><span style="opacity:0.5">:</span></span><span style="color:#C4A000">00</span><span style="color:#06989A"><span style="opacity:0.5">:</span></span><span style="color:#C4A000">00</span><span style="color:#06989A"><span style="opacity:0.5">][</span></span><span style="color:#06989A"><span style="opacity:0.5">][</span></span><span style="color:#06989A"><span style="opacity:0.5">] </span></span><span style="color:#4E9A06"><span style=""><span style="opacity:0.5">SUCCESS</span></span></span><span style="color:#06989A"><span style="opacity:0.5"> </span></span>Resolving elements
+<span style="color:#06989A"><span style="opacity:0.5">[</span></span><span style="color:#C4A000">--</span><span style="color:#06989A"><span style="opacity:0.5">:</span></span><span style="color:#C4A000">--</span><span style="color:#06989A"><span style="opacity:0.5">:</span></span><span style="color:#C4A000">--</span><span style="color:#06989A"><span style="opacity:0.5">][</span></span><span style="color:#06989A"><span style="opacity:0.5">][</span></span><span style="color:#06989A"><span style="opacity:0.5">] </span></span><span style="color:#3465A4"><span style=""><span style="opacity:0.5">START  </span></span></span><span style="color:#06989A"><span style="opacity:0.5"> </span></span>Resolving cached state
+<span style="color:#06989A"><span style="opacity:0.5">[</span></span><span style="color:#C4A000">00</span><span style="color:#06989A"><span style="opacity:0.5">:</span></span><span style="color:#C4A000">00</span><span style="color:#06989A"><span style="opacity:0.5">:</span></span><span style="color:#C4A000">00</span><span style="color:#06989A"><span style="opacity:0.5">][</span></span><span style="color:#06989A"><span style="opacity:0.5">][</span></span><span style="color:#06989A"><span style="opacity:0.5">] </span></span><span style="color:#4E9A06"><span style=""><span style="opacity:0.5">SUCCESS</span></span></span><span style="color:#06989A"><span style="opacity:0.5"> </span></span>Resolving cached state
+<span style="color:#06989A"><span style="opacity:0.5">[</span></span><span style="color:#C4A000">--</span><span style="color:#06989A"><span style="opacity:0.5">:</span></span><span style="color:#C4A000">--</span><span style="color:#06989A"><span style="opacity:0.5">:</span></span><span style="color:#C4A000">--</span><span style="color:#06989A"><span style="opacity:0.5">][</span></span><span style="color:#06989A"><span style="opacity:0.5">][</span></span><span style="color:#06989A"><span style="opacity:0.5">] </span></span><span style="color:#3465A4"><span style=""><span style="opacity:0.5">START  </span></span></span><span style="color:#06989A"><span style="opacity:0.5"> </span></span>Checking sources
+<span style="color:#06989A"><span style="opacity:0.5">[</span></span><span style="color:#C4A000">00</span><span style="color:#06989A"><span style="opacity:0.5">:</span></span><span style="color:#C4A000">00</span><span style="color:#06989A"><span style="opacity:0.5">:</span></span><span style="color:#C4A000">00</span><span style="color:#06989A"><span style="opacity:0.5">][</span></span><span style="color:#06989A"><span style="opacity:0.5">][</span></span><span style="color:#06989A"><span style="opacity:0.5">] </span></span><span style="color:#4E9A06"><span style=""><span style="opacity:0.5">SUCCESS</span></span></span><span style="color:#06989A"><span style="opacity:0.5"> </span></span>Checking sources
+
+<span style="color:#C4A000"><span style="">BuildStream Version 1.3.0+1032.g41813d3a.dirty
+</span></span><span style="color:#06989A"><span style="opacity:0.5">  Session Start: </span></span><span style="color:#C4A000">Wednesday, 05-12-2018 at 16:47:38</span>
+<span style="color:#06989A"><span style="opacity:0.5">  Project:       </span></span><span style="color:#C4A000">developing (/home/user/workspace/buildstream/buildstream/doc/examples/developing)</span>
+<span style="color:#06989A"><span style="opacity:0.5">  Targets:       </span></span><span style="color:#C4A000">hello.bst</span>
+
+<span style="color:#C4A000"><span style="">User Configuration
+</span></span><span style="color:#06989A"><span style="opacity:0.5">  Configuration File:      </span></span><span style="color:#C4A000">/home/user/workspace/buildstream/buildstream/doc/run-bst-7ocq4_a7/buildstream.conf</span>
+<span style="color:#06989A"><span style="opacity:0.5">  Log Files:               </span></span><span style="color:#C4A000">/home/user/workspace/buildstream/buildstream/doc/run-bst-7ocq4_a7/logs</span>
+<span style="color:#06989A"><span style="opacity:0.5">  Source Mirrors:          </span></span><span style="color:#C4A000">/home/user/workspace/buildstream/buildstream/doc/run-bst-7ocq4_a7/sources</span>
+<span style="color:#06989A"><span style="opacity:0.5">  Build Area:              </span></span><span style="color:#C4A000">/home/user/workspace/buildstream/buildstream/doc/run-bst-7ocq4_a7/build</span>
+<span style="color:#06989A"><span style="opacity:0.5">  Artifact Cache:          </span></span><span style="color:#C4A000">/home/user/workspace/buildstream/buildstream/doc/run-bst-7ocq4_a7/artifacts</span>
+<span style="color:#06989A"><span style="opacity:0.5">  Strict Build Plan:       </span></span><span style="color:#C4A000">Yes</span>
+<span style="color:#06989A"><span style="opacity:0.5">  Maximum Fetch Tasks:     </span></span><span style="color:#C4A000">10</span>
+<span style="color:#06989A"><span style="opacity:0.5">  Maximum Build Tasks:     </span></span><span style="color:#C4A000">4</span>
+<span style="color:#06989A"><span style="opacity:0.5">  Maximum Push Tasks:      </span></span><span style="color:#C4A000">4</span>
+<span style="color:#06989A"><span style="opacity:0.5">  Maximum Network Retries: </span></span><span style="color:#C4A000">2</span>
+
+<span style="color:#C4A000"><span style="">Pipeline
+</span></span><span style="color:#75507B">      cached</span> <span style="color:#C4A000">9afe69d645f0bee106749bc2101aae16ef437bb51e1b343ef1f16f04f0572efb</span> <span style="color:#3465A4"><span style="">base/alpine.bst</span></span> 
+<span style="color:#75507B">      cached</span> <span style="color:#C4A000">19f7c50c7a1db9ae4babe9d1f34f4cdbbf2428827d48673861fd1452d6c7e16b</span> <span style="color:#3465A4"><span style="">base.bst</span></span> 
+<span style="color:#75507B">      cached</span> <span style="color:#C4A000">faa419610e7309d36d15926a81a8d75bbc113443c23c8162e63843dd86b5f56a</span> <span style="color:#3465A4"><span style="">hello.bst</span></span> Workspace: /home/user/workspace/buildstream/buildstream/doc/examples/developing/workspace_hello
+<span style="color:#06989A"><span style="opacity:0.5">===============================================================================
+</span></span><span style="color:#06989A"><span style="opacity:0.5">[</span></span><span style="color:#C4A000">00</span><span style="color:#06989A"><span style="opacity:0.5">:</span></span><span style="color:#C4A000">00</span><span style="color:#06989A"><span style="opacity:0.5">:</span></span><span style="color:#C4A000">00</span><span style="color:#06989A"><span style="opacity:0.5">][</span></span><span style="color:#06989A"><span style="opacity:0.5">][</span></span><span style="color:#06989A"><span style="opacity:0.5">] </span></span><span style="color:#4E9A06"><span style=""><span style="opacity:0.5">SUCCESS</span></span></span><span style="color:#06989A"><span style="opacity:0.5"> </span></span>Build
+
+<span style="color:#C4A000"><span style="">Pipeline Summary
+</span></span><span style="color:#06989A"><span style="opacity:0.5">  Total:       </span></span><span style="color:#C4A000">3</span>
+<span style="color:#06989A"><span style="opacity:0.5">  Session:     </span></span><span style="color:#C4A000">0</span>
+<span style="color:#06989A"><span style="opacity:0.5">  Fetch Queue: </span></span><span style="color:#C4A000">processed </span><span style="color:#4E9A06">0</span><span style="color:#06989A"><span style="opacity:0.5">, </span></span><span style="color:#C4A000">skipped </span><span style="color:#C4A000">0</span><span style="color:#06989A"><span style="opacity:0.5">, </span></span><span style="color:#C4A000">failed </span><span style="color:#CC0000"><span style="opacity:0.5">0</span></span> 
+<span style="color:#06989A"><span style="opacity:0.5">  Build Queue: </span></span><span style="color:#C4A000">processed </span><span style="color:#4E9A06">0</span><span style="color:#06989A"><span style="opacity:0.5">, </span></span><span style="color:#C4A000">skipped </span><span style="color:#C4A000">0</span><span style="color:#06989A"><span style="opacity:0.5">, </span></span><span style="color:#C4A000">failed </span><span style="color:#CC0000"><span style="opacity:0.5">0</span></span>
+</pre></div>
diff --git a/tests/frontend/source_checkout.py b/tests/frontend/source_checkout.py
index 4e7541a31..08230ce5d 100644
--- a/tests/frontend/source_checkout.py
+++ b/tests/frontend/source_checkout.py
@@ -28,19 +28,28 @@ def generate_remote_import_element(input_path, output_path):
 
 
 @pytest.mark.datafiles(DATA_DIR)
-@pytest.mark.parametrize('with_workspace', [('workspace'), ('no-workspace')])
-def test_source_checkout(datafiles, tmpdir_factory, cli, with_workspace):
+@pytest.mark.parametrize(
+    "with_workspace,guess_element",
+    [(True, True), (True, False), (False, False)],
+    ids=["workspace-guess", "workspace-no-guess", "no-workspace-no-guess"]
+)
+def test_source_checkout(datafiles, cli, tmpdir_factory, with_workspace, guess_element):
     tmpdir = tmpdir_factory.mktemp("")
     project = os.path.join(datafiles.dirname, datafiles.basename)
     checkout = os.path.join(cli.directory, 'source-checkout')
     target = 'checkout-deps.bst'
     workspace = os.path.join(str(tmpdir), 'workspace')
+    elm_cmd = [target] if not guess_element else []
 
-    if with_workspace == "workspace":
-        result = cli.run(project=project, args=['workspace', 'open', '--directory', workspace, target])
+    if with_workspace:
+        ws_cmd = ['-C', workspace]
+        result = cli.run(project=project, args=["workspace", "open", "--directory", workspace, target])
         result.assert_success()
+    else:
+        ws_cmd = []
 
-    result = cli.run(project=project, args=['source-checkout', target, '--deps', 'none', checkout])
+    args = ws_cmd + ['source-checkout', '--deps', 'none'] + elm_cmd + [checkout]
+    result = cli.run(project=project, args=args)
     result.assert_success()
 
     assert os.path.exists(os.path.join(checkout, 'checkout-deps', 'etc', 'buildstream', 'config'))
diff --git a/tests/frontend/workspace.py b/tests/frontend/workspace.py
index baca869bf..c95eabccd 100644
--- a/tests/frontend/workspace.py
+++ b/tests/frontend/workspace.py
@@ -616,12 +616,16 @@ def test_list(cli, tmpdir, datafiles):
 @pytest.mark.datafiles(DATA_DIR)
 @pytest.mark.parametrize("kind", repo_kinds)
 @pytest.mark.parametrize("strict", [("strict"), ("non-strict")])
-@pytest.mark.parametrize("call_from", [("project"), ("workspace")])
-def test_build(cli, tmpdir_factory, datafiles, kind, strict, call_from):
+@pytest.mark.parametrize(
+    "from_workspace,guess_element",
+    [(False, False), (True, True), (True, False)],
+    ids=["project-no-guess", "workspace-guess", "workspace-no-guess"])
+def test_build(cli, tmpdir_factory, datafiles, kind, strict, from_workspace, guess_element):
     tmpdir = tmpdir_factory.mktemp('')
     element_name, project, workspace = open_workspace(cli, tmpdir, datafiles, kind, False)
     checkout = os.path.join(str(tmpdir), 'checkout')
-    args_pre = ['-C', workspace] if call_from == "workspace" else []
+    args_dir = ['-C', workspace] if from_workspace else []
+    args_elm = [element_name] if not guess_element else []
 
     # Modify workspace
     shutil.rmtree(os.path.join(workspace, 'usr', 'bin'))
@@ -644,14 +648,14 @@ def test_build(cli, tmpdir_factory, datafiles, kind, strict, call_from):
     # Build modified workspace
     assert cli.get_element_state(project, element_name) == 'buildable'
     assert cli.get_element_key(project, element_name) == "{:?<64}".format('')
-    result = cli.run(project=project, args=args_pre + ['build', element_name])
+    result = cli.run(project=project, args=args_dir + ['build'] + args_elm)
     result.assert_success()
     assert cli.get_element_state(project, element_name) == 'cached'
     assert cli.get_element_key(project, element_name) != "{:?<64}".format('')
 
     # Checkout the result
     result = cli.run(project=project,
-                     args=args_pre + ['checkout', element_name, checkout])
+                     args=args_dir + ['checkout'] + args_elm + [checkout])
     result.assert_success()
 
     # Check that the pony.conf from the modified workspace exists
@@ -1062,29 +1066,36 @@ def test_multiple_failed_builds(cli, tmpdir, datafiles):
 
 @pytest.mark.datafiles(DATA_DIR)
 @pytest.mark.parametrize('subdir', [True, False], ids=["subdir", "no-subdir"])
-def test_external_fetch(cli, datafiles, tmpdir_factory, subdir):
+@pytest.mark.parametrize("guess_element", [True, False], ids=["guess", "no-guess"])
+def test_external_fetch(cli, datafiles, tmpdir_factory, subdir, guess_element):
     # Fetching from a workspace outside a project doesn't fail horribly
     tmpdir = tmpdir_factory.mktemp('')
     element_name, project, workspace = open_workspace(cli, tmpdir, datafiles, "git", False)
+    arg_elm = [element_name] if not guess_element else []
 
     if subdir:
         call_dir = os.path.join(workspace, 'usr')
     else:
         call_dir = workspace
 
-    result = cli.run(project=project, args=['-C', call_dir, 'fetch', element_name])
+    result = cli.run(project=project, args=['-C', call_dir, 'fetch'] + arg_elm)
     result.assert_success()
 
     # We already fetched it by opening the workspace, but we're also checking
     # `bst show` works here
-    assert cli.get_element_state(project, element_name) == 'buildable'
+    result = cli.run(project=project,
+                     args=['-C', call_dir, 'show', '--deps', 'none', '--format', '%{state}'] + arg_elm)
+    result.assert_success()
+    assert result.output.strip() == 'buildable'
 
 
 @pytest.mark.datafiles(DATA_DIR)
-def test_external_push_pull(cli, datafiles, tmpdir_factory):
+@pytest.mark.parametrize("guess_element", [True, False], ids=["guess", "no-guess"])
+def test_external_push_pull(cli, datafiles, tmpdir_factory, guess_element):
     # Pushing and pulling to/from an artifact cache works from an external workspace
     tmpdir = tmpdir_factory.mktemp('')
     element_name, project, workspace = open_workspace(cli, tmpdir, datafiles, "git", False)
+    arg_elm = [element_name] if not guess_element else []
 
     with create_artifact_share(os.path.join(str(tmpdir), 'artifactshare')) as share:
         result = cli.run(project=project, args=['-C', workspace, 'build', element_name])
@@ -1094,22 +1105,24 @@ def test_external_push_pull(cli, datafiles, tmpdir_factory):
             'artifacts': {'url': share.repo, 'push': True}
         })
 
-        result = cli.run(project=project, args=['-C', workspace, 'push', element_name])
+        result = cli.run(project=project, args=['-C', workspace, 'push'] + arg_elm)
         result.assert_success()
 
-        result = cli.run(project=project, args=['-C', workspace, 'pull', '--deps', 'all', element_name])
+        result = cli.run(project=project, args=['-C', workspace, 'pull', '--deps', 'all'] + arg_elm)
         result.assert_success()
 
 
 @pytest.mark.datafiles(DATA_DIR)
-def test_external_track(cli, datafiles, tmpdir_factory):
+@pytest.mark.parametrize("guess_element", [True, False], ids=["guess", "no-guess"])
+def test_external_track(cli, datafiles, tmpdir_factory, guess_element):
     # Tracking does not get horribly confused
     tmpdir = tmpdir_factory.mktemp('')
     element_name, project, workspace = open_workspace(cli, tmpdir, datafiles, "git", True)
+    arg_elm = [element_name] if not guess_element else []
 
     # The workspace is necessarily already tracked, so we only care that
     # there's no weird errors.
-    result = cli.run(project=project, args=['-C', workspace, 'track', element_name])
+    result = cli.run(project=project, args=['-C', workspace, 'track'] + arg_elm)
     result.assert_success()
 
 
@@ -1147,15 +1160,17 @@ def test_external_close_other(cli, datafiles, tmpdir_factory):
 
 
 @pytest.mark.datafiles(DATA_DIR)
-def test_external_close_self(cli, datafiles, tmpdir_factory):
+@pytest.mark.parametrize("guess_element", [True, False], ids=["guess", "no-guess"])
+def test_external_close_self(cli, datafiles, tmpdir_factory, guess_element):
     # From inside an external workspace, close it
     tmpdir1 = tmpdir_factory.mktemp('')
     tmpdir2 = tmpdir_factory.mktemp('')
     # Making use of the assumption that it's the same project in both invocations of open_workspace
     alpha_element, project, alpha_workspace = open_workspace(cli, tmpdir1, datafiles, "git", False, suffix="-alpha")
     beta_element, _, beta_workspace = open_workspace(cli, tmpdir2, datafiles, "git", False, suffix="-beta")
+    arg_elm = [alpha_element] if not guess_element else []
 
-    result = cli.run(project=project, args=['-C', alpha_workspace, 'workspace', 'close', alpha_element])
+    result = cli.run(project=project, args=['-C', alpha_workspace, 'workspace', 'close'] + arg_elm)
     result.assert_success()
 
 
@@ -1172,11 +1187,13 @@ def test_external_reset_other(cli, datafiles, tmpdir_factory):
 
 
 @pytest.mark.datafiles(DATA_DIR)
-def test_external_reset_self(cli, datafiles, tmpdir):
+@pytest.mark.parametrize("guess_element", [True, False], ids=["guess", "no-guess"])
+def test_external_reset_self(cli, datafiles, tmpdir, guess_element):
     element, project, workspace = open_workspace(cli, tmpdir, datafiles, "git", False)
+    arg_elm = [element] if not guess_element else []
 
     # Command succeeds
-    result = cli.run(project=project, args=['-C', workspace, 'workspace', 'reset', element])
+    result = cli.run(project=project, args=['-C', workspace, 'workspace', 'reset'] + arg_elm)
     result.assert_success()
 
     # Successive commands still work (i.e. .bstproject.yaml hasn't been deleted)
diff --git a/tests/integration/shell.py b/tests/integration/shell.py
index 1cec21818..983cab6b5 100644
--- a/tests/integration/shell.py
+++ b/tests/integration/shell.py
@@ -358,13 +358,22 @@ def test_integration_devices(cli, tmpdir, datafiles):
 # Test that a shell can be opened from an external workspace
 @pytest.mark.datafiles(DATA_DIR)
 @pytest.mark.parametrize("build_shell", [("build"), ("nobuild")])
+@pytest.mark.parametrize("guess_element", [True, False], ids=["guess", "no-guess"])
 @pytest.mark.skipif(IS_LINUX and not HAVE_BWRAP, reason='Only available with bubblewrap on Linux')
-def test_integration_external_workspace(cli, tmpdir_factory, datafiles, build_shell):
+def test_integration_external_workspace(cli, tmpdir_factory, datafiles, build_shell, guess_element):
     tmpdir = tmpdir_factory.mktemp("")
     project = os.path.join(datafiles.dirname, datafiles.basename)
     element_name = 'autotools/amhello.bst'
     workspace_dir = os.path.join(str(tmpdir), 'workspace')
 
+    if guess_element:
+        # Mutate the project.conf to use a default shell command
+        project_file = os.path.join(project, 'project.conf')
+        config_text = "shell:\n"\
+                      "  command: ['true']\n"
+        with open(project_file, 'a') as f:
+            f.write(config_text)
+
     result = cli.run(project=project, args=[
         'workspace', 'open', '--directory', workspace_dir, element_name
     ])
@@ -373,9 +382,10 @@ def test_integration_external_workspace(cli, tmpdir_factory, datafiles, build_sh
     result = cli.run(project=project, args=['-C', workspace_dir, 'build', element_name])
     result.assert_success()
 
-    command = ['shell']
+    command = ['-C', workspace_dir, 'shell']
     if build_shell == 'build':
         command.append('--build')
-    command.extend([element_name, '--', 'true'])
+    if not guess_element:
+        command.extend([element_name, '--', 'true'])
     result = cli.run(project=project, cwd=workspace_dir, args=command)
     result.assert_success()