28 Commits (f2dbf80badc8c7385a7b44bb040ae5e8550e7e60)

Author	SHA1	Message	Date
James Bardin	7a183a0e90	don't assert set block length with unknowns ... If a planned NestingList block value looks like it may represent a dynamic block, we don't check the length since it may be unknown. This check was missing in the NestingSet case, but it applies for the same reason. <	7 years ago
James Bardin	bfa5e7f811	actual value may be unknown in nested list ... When checking AssertObjectCompatible, we need to allow for a possible unkown nested list block, just as we did for a set in 0b2cc62.	7 years ago
Martin Atkins	332010fd56	plans/objchange: Fix handling of dynamic block placeholders ... If a dynamic block (in the HCL dynamic block extension sense) has an unknown value for its for_each argument, it gets expanded to a single placeholder block with all of its attributes set to a unknown values. We can use this as part of a heuristic to relax our object compatibility checks for situations where the plan included an object that appears to be (but isn't necessarily) such a placeholder, allowing for the fact that the one placeholder block could be replaced with zero or more real blocks once the for_each value is known. Previously our heuristic was too strict: it would match only if the only block present was a dynamic placeholder. In practice, users may mix dynamic blocks with static blocks of the same type, so we need to be more liberal to avoid generating incorrect incompatibility errors in such cases.	7 years ago
Martin Atkins	95e5ef13a7	vendor: go get github.com/zclconf/go-cty@master ... This includes a more comprehensive implementation of Value.GoString, along with various other changes that don't affect Terraform.	7 years ago
Martin Atkins	88e76fa9ef	configs/configschema: Introduce the NestingGroup mode for blocks ... In study of existing providers we've found a pattern we werent previously accounting for of using a nested block type to represent a group of arguments that relate to a particular feature that is always enabled but where it improves configuration readability to group all of its settings together in a nested block. The existing NestingSingle was not a good fit for this because it is designed under the assumption that the presence or absence of the block has some significance in enabling or disabling the relevant feature, and so for these always-active cases we'd generate a misleading plan where the settings for the feature appear totally absent, rather than showing the default values that will be selected. NestingGroup is, therefore, a slight variation of NestingSingle where presence vs. absence of the block is not distinguishable (it's never null) and instead its contents are treated as unset when the block is absent. This then in turn causes any default values associated with the nested arguments to be honored and displayed in the plan whenever the block is not explicitly configured. The current SDK cannot activate this mode, but that's okay because its "legacy type system" opt-out flag allows it to force a block to be processed in this way anyway. We're adding this now so that we can introduce the feature in a future SDK without causing a breaking change to the protocol, since the set of possible block nesting modes is not extensible.	7 years ago
Martin Atkins	87fe6cbecd	plans/objchange: Don't panic when prior state contains nested map blocks ... We were using the wrong cty operation to access map members, causing a panic whenever a prior value was present for a resource type with a nested block backed by a map value.	7 years ago
Martin Atkins	c5aa5c68bc	plans/objchange: Don't panic when dynamic-typed attrs are present ... When dynamically-typed attributes are in the schema, we use different conventions for representing nested blocks containing them (using tuples and objects instead of lists and maps). The normalization code here doesn't deal with those because the legacy SDK never generates them, but we must still pass them through properly or else other SDKs will be blocked from using dynamic attributes. Previously this function would panic in that situation. Now it will just pass through nested blocks containing dynamic attribute values entirely as-is, with no normalization whatsoever. That's okay, because the scope of this function is only to normalize inconsistencies that the legacy SDK is known to produce, and the legacy SDK never produces dynamic-typed attributes.	7 years ago
James Bardin	e50be82da4	don't add empty blocks in ProposedNewObject ... If the config contained a null block, don't convert it to a block with empty values for the proposed new value.	7 years ago
Martin Atkins	c280c27d87	plans/objchange: func NormalizeObjectFromLegacySDK ... Now that we have an opt-out to let the legacy SDK return values that are inconsistent with the new conventions for representing configuration, various parts of Terraform must now be prepared to deal with inconsistencies. This function normalizes the most egregious inconsistencies relating to the representation of nested blocks, freeing any recipient of its result from worrying about these inconsistencies itself.	7 years ago
Martin Atkins	0b2cc6298b	plans/objchange: Fix panic in AssertObjectCompatible with set blocks ... Our usual "ground rules" for mapping configschema to cty call for the collection values representing nested block types to always be known and non-null, using an empty collection to represent the absense of any blocks of that type so that users can always safely use length(...) etc on them without worrying about them sometimes being null. However, due to some different behaviors in the legacy SDK we've allowed it an exception to this rule which means that we can see unknown and null collections in these positions in object values returned from provider operations like PlanResourceChange and ApplyResourceChange when the legacy SDK opt-out is activated. As a consequence of this, we need to be mindful in our safety check functions, like AssertObjectCompatible here, of tolerating these non-ideal situations to allow the safety checks to complete. We run these checks even when the provider requests an opt-out, because we want to note any inconsistencies as WARNING level log lines to aid in debugging.	7 years ago
Martin Atkins	e831182c8d	plans/objchange: Hide sensitive attribute values in error messages ... Since these error messages get printed in Terraform's output and we encourage users to share them as part of bug reports, we should avoid including sensitive information in them to reduce the risk of accidental exposure.	7 years ago
Martin Atkins	fec6e0328d	plans/objchange: AssertPlanValid function ... Completing our set of provider result safety-check functions, AssertPlanValid checks a result from a provider's PlanResourceChange to make sure it doesn't propose a change that is not valid within the user model of Terraform. Specifically, it forbids the provider from planning a value that contradicts what the user gave in configuration, which is important to ensure that making a reference to an attribute elsewhere in the configuration will produce exactly the given result, as users reasonably expect. Providers _are_ allowed (and, in fact, required) to make changes to any Computed attribute values declared in the schema in order to fill in the default values that the provider has generated. Later checks during the apply phase will ensure that the provider remains true to these planned values, to ensure that Terraform can keep its promise of doing exactly what was planned or presenting an error explaining why not.	7 years ago
Martin Atkins	312d798a89	core: Restore our EvalReadData behavior ... In an earlier commit we changed objchange.ProposedNewObject so that the task of populating unknown values for attributes not known during apply is the responsibility of the provider's PlanResourceChange method, rather than being handled automatically. However, we were also using objchange.ProposedNewObject to construct the placeholder new object for a deferred data resource read, and so we inadvertently broke that deferral behavior. Here we restore the old behavior by introducing a new function objchange.PlannedDataResourceObject which is a specialized version of objchange.ProposedNewObject that includes the forced behavior of populating unknown values, because the provider gets no opportunity to customize a deferred read. TestContext2Plan_createBeforeDestroy_depends_datasource required some updates here because its implementation of PlanResourceChange was not handling the insertion of the unknown value for attribute "computed". The other changes here are just in an attempt to make the flow of this test more obvious, by clarifying that it is simulating a -refresh=false run, which effectively forces a deferred read since we skip the eager read that would normally happen in the refresh step.	7 years ago
Martin Atkins	c794bf5bcc	plans/objchange: Don't presume unknown for values unset in config ... Previously we would construct a proposed new state with unknown values in place of any not-set-in-config computed attributes, trying to save the provider a little work in specifying that itself. Unfortunately that turns out to be problematic because it conflates two concerns: attributes can be explicitly set in configuration to an unknown value, in which case the final result of that unknown overrides any default value the provider might normally populate. In other words, this allows the provider to recognize in the proposed new state the difference between an Optional+Computed attribute being set to unknown in the config vs not being set in the config at all. The provider now has the responsibility to replace these proposed null values with unknown values during PlanResourceChange if it expects to select a value during the apply step. It may also populate a known value if the final result can be predicted at plan time, as is the case for constant defaults specified in the provider code. This change comes from a realization that from core's perspective the helper/schema ideas of zero values, explicit default values, and customizediff tweaks are all just examples of "defaults", and by allowing the provider to see during plan whether these attributes are being explicitly set in configuration and thus decide whether the default will be provided immediately during plan or deferred until apply.	7 years ago
Martin Atkins	7216049fdb	plans/objchange: Improve precision of AssertObjectCompatible with sets ... Previously we were just asserting that the number of elements didn't grow between planned and actual. We still can't precisely correlate elements in sets with unknown values, but here we adapt some logic we added earlier to config/hcl2shim to ensure that we can find a plausible correlation for each element in each set to at least one element in the other set, and thus catch more cases where set elements might vanish or appear between plan and apply, for improved safety. This will still generate false negatives in some cases where unknown values are present due to having to assume correlation is intended wherever it is possible, but we'll catch situations where the actual value is obviously contrary to what was planned.	7 years ago
James Bardin	78256ae225	return early when comparing Null values	7 years ago
James Bardin	e93d69f18b	more nil/known checks before val.LengthInt	7 years ago
James Bardin	e08a388d3c	check IsKnown on values that may panic	7 years ago
Martin Atkins	9b4b43c077	plans/objchange: Don't panic when a prior value with a set is null ... ProposedNewObject intentionally replaces a null prior with an unknown prior in order to easily fill in unknown values where they "show through" under values not set explicitly in config, but it was failing to handle that situation when dealing with nested blocks that are backed by sets.	7 years ago
Kristin Laemmert	c661157999	plans/objchange: further harden ProposedNewObject against ~weird~ ... incoming values Addresses an odd state where the priorV of an object to be changed is known but null. While this situation should not happen, it seemed prudent to ensure that core is resilient to providers sending incorrect values (which might also occur with manually edited state).	7 years ago
Kristin Laemmert	2a8aa6a139	plans/objchange: if priorV is unknown, fall through to the recursive call to `ProposedNewObject`	7 years ago
Martin Atkins	32974549cd	plans/objchange: Fix handling of unknown in AssertValueCompatible ... We need to check for the known-ness of the prior value before we check for the null-ness of actual, because it's valid for an unknown value to become a null.	7 years ago
Martin Atkins	8048e9a585	plans/objchange: Don't panic if old or new values are null	7 years ago
Martin Atkins	1aa9ac14cc	plans/objchange: LongestCommonSubsequence ... This algorithm is the usual first step when generating diffs. This package is a bit of a strange home for it, but since it works with changes to cty.Value this feels more natural than any other place it could be.	7 years ago
Martin Atkins	3f8a973846	plans/objchange: when prior is null, computed attributes are unknown	7 years ago
Martin Atkins	549544f201	configschema: Handle nested blocks containing dynamic-typed attributes ... We need to make the collection itself be a tuple or object rather than list or map in this case, since otherwise all of the elements of the collection are constrained to be of the same type and that isn't the intent of a provider indicating that it accepts any type.	7 years ago
Martin Atkins	4c78539c2b	plans/objchange: AssertObjectSuperset function ... This function's goal is to ensure that the "final" plan value produced by a provider during the apply step is always consistent with the known parts of the planned value produced during the plan step. Any error produced here indicates a bug in the provider.	7 years ago
Martin Atkins	0317da9911	plans/objchange: logic for merging prior state with config ... This produces a "proposed new state", which already has prior computed values propagated into it (since that behavior is standard for all resource types) but could be customized further by the provider to make the "_planned_ new state". In the process of implementing this it became clear that our configschema DecoderSpec behavior is incorrect, since it's producing list values for NestingList and map values for NestingMap. While that seems like it should be right, we should actually be using tuple and object types respectively to allow each block to have a different runtime type in situations where an attribute is given the type cty.DynamicPseudoType. That's not fixed here, and so without a further fix list and map blocks will panic here. The DecoderSpec implementation will be fixed in a subsequent commit.	7 years ago