It was initially assumed that `nodeType` needed to rebuild the type from scratch, but this is not the case anymore. The existing type constructors are now used in `nodeType` to make it more readable. In doing this some bugs in type strings were found and fixed, along with adding the real package name to the type.
As `ptrOf` is now the only place that pointer types are constructed, it is feasible to cache the pointer type on the value type. To ensures that we have a consistent pointer type for any value type.
This adds `itype.str` which is a string representation of the type built when the type is built. The goal is to make type comparison simpler and centralise the creation of types just to constructors and `nodeType`. `nodeType` continues to build types in parts so to reuse underlying types better.
Make use of fs.FS (new to go 1.16) to allow for reading source files from diverse filesystems (local, embed, custom).
* `Options` has a new field `SourcecodeFilesystem fs.FS` so users can supply their own read-only filesystem containing source code.
* Defaults to the local filesystems (via `RealFS` - a thin `os.Open` wrapper complying with `fs.FS`) so regular users should see no change in behaviour.
* When no filesystem is available (e.g. WASM, or if you want to embed files to retain single binary distribution) an alternative filesystem is preferable to using `Eval(string)` as that requires the stringy code to be a single file monolith instead of multiple files. By using an `fs.FS` we can use `EvalPath()` and gain the ability to handle multiple files and packages.
* You can make use of embed filesystems (https://pkg.go.dev/embed) and custom filesystems obeying the `fs.FS` interface (I use one for http served zip files when targeting wasm as there is no local filesystem on wasm). Tests can make use of `fstest.Map`.
* NOTE: This does NOT affect what the running yaegi code considers its local filesystem, this is only for the interpreter finding the source code.
See `example/fs/fs_test.go` for an example.
Fixes#1200.
Add getConcreteType to retrieve the concrete type of a nested interface
value implementing a specific interface for which a wrapper exists.
If method resolution fails at runtime, a panic is now issued instead
of an error message and continue.
Fixes#1187.
Store the interpreter value of the interface object to wrap as
a field called IValue, at offset 0 in wrapper structures.
Update extract to include IValue field.
In typeAssert, detect interface wrapper, and dereference the
interpreter value from IValue wrapper field.
Fixes#1166.
### Background
#1102 changed how `Interpreter.Use` interprets export paths such that the last path component is stripped and used as the package name. This resulted in #1139 - attempting to Use an export with only one path component, such as `foo`, would result in the import path being `.`.
### Breaking API Change
This PR changes the signature of `Interpreter.Use` from `Use(Exports)` to `Use(Exports) error`.
### Fix for #1139
With this PR, if Use is called with an incomplete export path, such as `foo`, Use will return an error.
Use YAEGI_SPECIAL_STDIO env boolean to overwrite os.Stdxxx by
non file descriptors io.Writer / io.Reader interfaces. It is set
to true when testing to allow redirection to byte buffers.
The default behaviour is now to preserve the original concrete type
when sandboxing stdio, which maintains compatibility.
Fixes#1092.
Some binary method calls were wrongly rejected. There is still
some ambiguous cases as binary method signature may include or
not the receiver as first argument, depending on how the method
was resolved.
With this fix, `import "golang.org/x/net/html"` doesn't panic
anymore, but not all tests are passing yet, i.e.
`yaegi test golang.org/x/net/html` still has failures, to be
investigated.
Fixes#1107.
The heuristic to generate a package name identifier was incorrect. Now for binary packages, the package identifier is obtained by a symbol, generated by extract, which contains the string argument of package statement in source file. This should ensure an always correct default package identifier.
Fixes#1095.
This feature was already present, but part of REPL only.
It's now also possible to apply it when evaluating a string
(-e flag). Default package names collision handling is no
longer hard-coded.
With -e flag, the eval result is now printed if valid, allowing
simpler commands:
yaegi -e 'reflect.TypeOf(fmt.Printf)'
instead of:
yaegi -e 'println(reflect.TypeOf(fmt.Printf))'
Fixes#1084.
The interpreter is exposed to itself through a "Self" var which
is set on "Use" of the interpreter package.
It allows meta-programming features, for example using "Eval" in
the current interpreter context, or enabling self-inspection
capabilities.
The first change forces a variable definition to reallocate a
new memory slot to avoid corrupting a previously defined one in
a loop block.
The second change ensures that the frame clone operations obtains
a copy of the original data slice, to preserve the original context
set in a loop.
Fixes#1035.
As mentioned in #1030, when an Eval panic, it is print with `fmt.Println()` and not to the configured `interp.Options.Stderr`. According to https://github.com/traefik/yaegi/blob/master/interp/interp.go#L210, it should be removed in future version so I'm not sure if this pull request is necessary. However, it could fix the issue in the meanwhile.
Fixes#1030.
In some cases, the global character of a value was lost, leading to
undefined behaviour. Now a node level field of -1 means that the value
is global, and that it should be accessed from the root data frame.
Fixes#993.
Often enough when debugging, one does not know exactly what argument
should be given to Symbols, as it's not always clear in which
scope/namespace the symbol one is looking for is stored in.
Therefore, this change enables the Symbols method to now take the empty
string as an argument, which results in all the known symbols to be
returned (keyed by import path).
As a consequence, when an non-empty argument is given, the returned
result should be similar to what we had before, except it is now
returned as the sole entry of an encompassing map.
In addition, the "binary" symbols (i.e. the ones ingested through a
Use call), are now also taken into account.
Since the introduction of restricted stdlib and syscall symbols, the
capability of yaegi to interpret itself was broken.
The use of unrestricted symbols is now also controlled by environment
variables, to allow propagation accross nested interpreters.
The interpreter Panic symbol was not wrapped, this is fixed now.
the import path resolution was failing if the working directory was
outside of GOPATH.
The documentation and readme have been ajusted.
Fixes#890.
When working with an untyped const expression involving a division, if
the default type of the result should be an int (for example because the
default types of all the operands are ints as well), then we should make
sure that the operation that is applied is indeed an integer division,
and that the type of the result is not a float.
This is achieved by using the QUO_ASSIGN operator, instead of the QUO
operator.
This should fix several problems lurking around, and it notably fixes
one of the visible consequences, which is a systematic panic when using
the REPL as a "calculator".
This incidentally also allows us to revert what was done in
5dfc3b86dc since it now turns out it was
just a hack to fix one of the symptoms.
Fixes#864
This change allows the interpreter to execute tests and benchmarks
functions provided by packages.
The test subcommand is similar to the "go test" command and
all the relevant flags have been kept.
The ability to evaluate a directory or a package has also been added.
A new method Symbol to access exported symbol values of an interpreted
package has been added. This method is used by the test subcommand.
An EvalTest method has been added to evaluate all Go files, including "*_test.go".
The testing packages from the standard library have been added to stdlib used
symbols.
This change fixes two distinct data races:
1) some global vars of type *itype of the interp package are actually
mutated during the lifecycle of an Interpreter. Even worse: if more than
one Interpreter instance are created and used at a given time, they are
actually racing each other for these global vars.
Therefore, this change replaces these global vars with generator
functions that create the needed type on the fly.
2) the symbols given as argument of Interpreter.Use were directly copied
as reference (since they're maps) when mapped inside an Interpreter
instance. Since the usual case is to give the symbols from the stdlib
package, it means when the interpreter mutates its own symbols in
fixStdio, it would actually mutate the corresponding global vars of the
stdlib package. Again, this is at least racy as soon as several
instances of an Intepreter are concurrently running.
This change fixes the race by making sure Interpreter.Use actually
copies the symbol values instead of copying the references.
The goal is to provide greater control of input, output and error
streams of the interpreter. It is now possible to specify those
as options when creating a new interpreter. The provided values
are propagated to relevant stdlib symbols (i.e fmt.Print, etc).
Care is taken to not update the global variables os.Stdout, os.Stdin
and os.Stderr, as to not interfere with the host process.
The REPL function is now simplified. The deprecated version is removed.
The tests are updated to take advantage of the simplified access
to the interpreter output and errors.
Fixes#752.
In interactive mode, a line starting with the "func" keyword is usually
"wrapped", by prepending to it a "package main" statement, to make it
a valid piece of Go source code.
However, when the line is actually an anonymous function call, such as:
func() { println(3) }()
then this wrapping is not enough, as this is not valid Go in the global
context. Therefore, this kind of of expression must also be wrapped
inside a main func (as is the default case for most REPL inputs).
Since the detection and handling of such a case turned out to be quite
unelegant, this PR instead introduces a retrying phase when a parsing
error occurs for a particular class of cases. That is to say, when a
"func expression" wrapped in a main package fails to be parsed, it is
then wrapped in a main func before parsing is retried.
N.B. TestEvalScanner has been disabled for this change, because the additional test cases revealed a (most-likely already existing) data race.
Fixes#721
The input scanning is now performed in a sub goroutine and
the interrupt is listened in another goroutine, either to cancel Eval
or to cancel the current line scan.
Entering a '\n' after a 'Ctrl-C` to get the prompt is
not necessary anymore.
The recent changes that added some redeclaration checks implicitly added more
strictness related to namespaces and scopes which, among other things, broke
some uses that "accidentally" used to work.
For example, given
const script1 = `
import "fmt"
// more code
`
const script2 = `
import "fmt"
// some other code
`
If one Evals script1, then script2, with the same interpreter, without
specifying any scope, as the two fragments would be considered part of the same
(.go file) scope by default, a redeclaration error would be triggered because
import "fmt" is seen twice.
A work-around would have been to specify (a different) i.Name before each Eval
call, so that each script is considered as coming from a different .go file, and
hence are respectively in different scopes with respect to imports.
That lead us to realize we had to make specifying things such as file-scope, and
"incremental mode" (aka REPL), more obvious in the context of an Eval call.
In addition, we want to lay down the foundations for Yaegi being able to behave
more like the go tool wrt to various inputs, i.e. it should be able to take a
package directory, or an import path, as input, instead of just a .go file.
Hence the introduction of a new kind of Eval method (whose signature is not fixed yet):
func (interp *Interpreter) EvalPath(path string) (res reflect.Value, err error)
It partially solves the problem described above because:
1. the path given to EvalPath can be used as the file-scope hint mentioned
above, for now (even though the related implementation details might change).
2. Eval always runs in incremental mode, whereas EvalPath always runs in
non-incremental mode, hence clarifying the situation in that respect.
And to avoid confusion, the Name field of Interpreter is now non-exported,
since it is somewhat redundant with the path argument of EvalPath.
Note that #731 is not fully fixed (and might never be), as a requirement of the
proposed solution is to move the input bits of code into respective files
(instead of leaving them as strings).
Finally, some related bugfixes, documention changes, and some refactoring have
been included. Notably, there is no "empty scope" anymore, i.e. name defaults
to "_.go" when it is not specified.
Updates #731Fixes#778Fixes#798Fixes#789
Co-authored-by: Marc Vertes <mvertes@free.fr>
Avoid goroutines leak, accumulation of defered functions and
spurious resets of signal handlers. Effectively catch interrupt
signal (Ctrl-C) to cancel current eval.
Fixes#713.
So far the REPL loop was treating any parsing error coming from
go/parser to generate the AST, as having occurred because the source
code was not yet complete (unfinished block). And it was therefore
ignoring all of them.
However, some of these errors are legitimate, and must be caught as soon
as they occur, otherwise the REPL cycle would stay in an errored state
forever (even when the block terminates), without the user getting any
feedback about it.
Therefore, this change adds an extra check when a parsing error occurs,
i.e. it verifies that it looks like an "EOF" error (unfinished block)
before it ignores it (as the user is supposed to terminate the block
eventually). Otherwise the error is treated just like a "non-parsing"
(cfg, gta, ...) error and printed out.
Fixes#637
* fix: constant definition loop on out of order vars
* fix: do not wire global varDecl
* fix: wire and execute global vars
* chore: add tests
* fix: refactor and lint
* feature: restrict symbols which can exit the interpreter process
Some symbols such as os.Exit or log.Fatal, which make the current process
to exit, are now restricted. They are replaced by a version which panics
instead of exiting, as panics are recovered by Eval.
The restricted os.FindProcess version is identical to the original
except it errors when trying to return the self process, in order to
forbid killing or signaling the interpreter process from script.
The os/exec symbols are available only through unrestricted package.
The original symbols are stored in an unrestricted package, which
requires an explicit Use, as for unsafe and syscall packages.
The Use() interpreter method has been slightly modified to allow inplace
updating of package symbols, allowing to replace some symbols but not
the entire imported package.
A command line option -unrestricted has been added to yaegi CLI to use
the unrestricted symbols.
Fixes#486.
* fix: lint
* fix: make interpreter methods discoverable by runtime
When generating an interface wrapper, lookup existing wrappers by method
to get the one with the biggest set of methods implemented by interpreter.
A string method is also added to wrappers, in order to provide a string
representation of the interpreter value rather than the wrapper itself
(at least for %s and %v verbs).
This allows the runtime to pickup an interpreter method automatically
even if the conversion to the interface is not specified in the script. As
in Go spec, it is enough for the type to implement the required methods.
A current limitation is that only single wrappers can be instantiated,
not allowing to compose interfaces.
This limitation can be removed when the Go reflect issue
https://github.com/golang/go/issues/15924 is fixed.
Fixes#435.
* test: add a simpler test
