fix: avoid checking the schema in case of syntax errors

[i4ki]

The invalid config below:

stack {
    wants = 
}

generates an error when calling the hashicorp parse.ParseHCL() function but it populate its parse.Files() with an invalid data structure for the file's body... for the case above, it creates an attribute with name "wants" and value of type cty.DynamicValue that's not even nullable (attrVar.IsNull() returns false)...

So we cannot have syntax error + schema errors because they do not provide partial correct nodes.

The fix was making terramate check the schema only for the files successfully parsed (valid HCL).

I got this issue while experimenting with the VSCode extension. The Language Server crashed with log below:

attribute=wants stack=
2022-06-14T13:09:43+01:00 TRC Iterate over values. action=assignSet()
panic: can't use ElementIterator on unknown value

goroutine 22 [running]:
github.com/zclconf/go-cty/cty.Value.ElementIterator({{{0x7776c8?, 0x953768?}}, {0x6b9120?, 0x9534a0?}})
	/home/i4k/go/pkg/mod/github.com/zclconf/go-cty@v1.8.3/cty/value_ops.go:1118 +0xd8
github.com/mineiros-io/terramate/hcl.assignSet({0xc000258744, 0x5}, 0xc0001431d0, {{{0x7776c8?, 0x953768?}}, {0x6b9120?, 0x9534a0?}})
	/home/i4k/go/pkg/mod/github.com/mineiros-io/terramate@v0.1.5/hcl/hcl.go:652 +0x37c
github.com/mineiros-io/terramate/hcl.parseStack(0xc000143180, 0xc000245200)
	/home/i4k/go/pkg/mod/github.com/mineiros-io/terramate@v0.1.5/hcl/hcl.go:739 +0x919
github.com/mineiros-io/terramate/hcl.(*TerramateParser).parseTerramateSchema(0xc00028f950)
	/home/i4k/go/pkg/mod/github.com/mineiros-io/terramate@v0.1.5/hcl/hcl.go:1142 +0xb2f
github.com/mineiros-io/terramate/hcl.(*TerramateParser).Parse(0xc00028f950)
	/home/i4k/go/pkg/mod/github.com/mineiros-io/terramate@v0.1.5/hcl/hcl.go:207 +0x72
github.com/mineiros-io/terramate-ls.checkFiles({0xc00014bb40, 0x2, 0x2?}, {0xc0001f0237, 0x61}, {0xc000130c60, 0x146})
	/home/i4k/src/mineiros/terramate-ls/ls.go:401 +0x128
github.com/mineiros-io/terramate-ls.(*Server).checkAndReply(0xc0001f0230?, {0x777658, 0xc00012fc80}, 0xc00014ba60, {0xc0001f0237, 0x61}, {0xc000130c60, 0x146})
	/home/i4k/src/mineiros/terramate-ls/ls.go:328 +0x156
github.com/mineiros-io/terramate-ls.(*Server).handleDocumentOpen(0x2aa?, {0x777658, 0xc00012fc80}, 0xc00014f7b8?, {0x7fee44fc1f18, 0xc00025a420}, {{0x776d10, 0xc0001d84d0}, 0xff, {0x0, ...}, ...})
	/home/i4k/src/mineiros/terramate-ls/ls.go:188 +0x11f
github.com/mineiros-io/terramate-ls.(*Server).Handler(0xc000132510, {0x777658, 0xc00012fc80}, 0xc00014ba60, {0x7fee44fc1f18?, 0xc00025a420?})
	/home/i4k/src/mineiros/terramate-ls/ls.go:93 +0x4ff
go.lsp.dev/jsonrpc2.(*conn).run(0xc000100c80, {0x777658, 0xc00012fc80}, 0xc0001d8790)
	/home/i4k/go/pkg/mod/go.lsp.dev/jsonrpc2@v0.10.0/conn.go:206 +0x24b
created by go.lsp.dev/jsonrpc2.(*conn).Go
	/home/i4k/go/pkg/mod/go.lsp.dev/jsonrpc2@v0.10.0/conn.go:189 +0xb0
[Error - 1:09:43 PM] Connection to server got closed. Server will not be restarted.

[codecov]

Codecov Report

Merging #396 (ab82f6c) into main (3830aae) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #396      +/-   ##
==========================================
- Coverage   69.63%   69.62%   -0.02%     
==========================================
  Files          37       37              
  Lines        7276     7270       -6     
==========================================
- Hits         5067     5062       -5     
+ Misses       1959     1958       -1     
  Partials      250      250              

Flag	Coverage Δ
tests	69.62% <100.00%> (-0.02%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
hcl/hcl.go	87.55% <100.00%> (-0.09%)	⬇️
manager.go	63.10% <0.00%> (+0.24%)	⬆️

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[katcipis]

"generates an error when calling the hashicorp parse.ParseHCL() function but it populate its parse.Files() with an invalid data structure for the file's body... for the case above, it creates an attribute with name "wants" and value of type cty.DynamicValue that's not even nullable (attrVar.IsNull() returns false)..."

[soerenmartius]

lgtm! Good job @i4ki